Approaches to improving symptom appraisal: a systematic literature review

Abstract

Objectives

Poor symptom appraisal (detection, interpretation and response to symptoms) plays a major role in prolonged prediagnosis interval in various health conditions. Theories and models have been proposed to study the symptom appraisal process but how they could be employed to improve symptom appraisal remains unclear. We therefore aimed to review approaches to improving symptom appraisal in the literature and to develop a theoretical framework that could guide the development of approaches to improving symptom appraisal among individuals in the general population.

Design

Systematic review.

Data sources

Medline, Web of Science, PsycINFO, Embase, CINAHL and Scopus were searched from inception to 30 March 2021.

Eligibility criteria

We included original articles in English in which approaches to improve the detection, interpretation or response to symptoms for symptomatic individuals were described. We excluded articles in which approaches were developed to improve symptom appraisal among healthcare professionals.

Data extraction and synthesis

A predefined data extraction form was used to extract the development, characteristics and evaluation of approaches to improving symptom appraisal. This formed the basis for the narrative synthesis.

Results

Of 19 046 publications identified from the literature search, 112 were selected for full-text review and 29 approaches comprising provision of knowledge of symptoms/signs and additional components (eg, symptom self-examination and comparison) for symptom appraisal were included in the synthesis. Less than half (41.4%) of these approaches were developed based on theories/models. Interestingly, despite the variety of theories/models adopted in developing these approaches, the components of these approaches were similar.

Conclusion

Symptom appraisal is an essential process in a patient’s journey that can be targeted to facilitate early diagnosis but is largely unstudied. Building on the literature, we proposed a theoretical framework and approaches to improving symptom appraisal. This could facilitate early identification of a variety of health conditions in the general population.

Trial registration number

CRD42021279500.

Correspondence to Professor Julian Thumboo; [email protected]

Strengths and limitations of this study

• This systematic review was built on a comprehensive search strategy, which was developed and refined iteratively using multiple preliminary searches.

• A narrative analysis allowed for deeper insights into (1) the development, implementation and evaluation of approaches to improving symptom appraisal and (2) the adopted theories and models in the literature.

• A theory-based framework was proposed, which can provide guidance for the development of approaches to improving symptom appraisal.

• Only free-text search was conducted in Web of Science and Scopus, which do not have controlled vocabularies.

Introduction

Prolonged prediagnosis interval between symptom onset and diagnosis, also referred to as diagnostic delay, remains an unmet need among patients with various health conditions such as cancer and autoimmune rheumatic diseases (ARDs) and results in poor patient outcomes.^1–8 Prediagnosis interval comprises largely the symptom appraisal interval between symptom onset and the first visit to healthcare professionals. Using the general model of total patient delay proposed by Andersen and Cacioppo, symptom appraisal interval constituted the majority (more than 60%) of the total duration of delay among patients with various cancers.⁹ In a systematic review of prediagnosis interval among patients with rheumatoid arthritis (RA), the most common ARD, by Barhamain et al, symptom appraisal interval was found to be longer than intervals between the first visit to healthcare professionals and diagnosis (weighted average: 3.4 vs 2.1–2.9 months).¹⁰

Symptom appraisal is a process an individual undertakes when symptoms (bodily changes) are noticed till a decision is made on whether an action needs to be taken in response to the symptoms (bodily changes).¹¹ During the symptom appraisal interval, symptoms are being appraised and misperception of symptoms (bodily changes) may occur. Individuals may not perceive their symptoms as a health concern that requires prompt medical attention, and hence may not seek help from healthcare professionals or do so in a timely manner.¹² Poor symptom appraisal has been shown to be a major cause of prolonged symptom appraisal interval and prediagnosis interval.^13–17 In the meta-analysis by Petrova et al, poor symptom knowledge, wrong interpretation of symptoms, and negative beliefs about cancer were significantly associated with longer symptom appraisal/help-seeking intervals among patients with various cancers.¹⁶ In the systematic review by Stack et al, many patients with recent-onset RA reported that they were unaware of the significance of their symptoms before they were diagnosed and that they would have sought help earlier if they had more knowledge of RA and its symptoms.¹⁴

It is thus important to develop approaches to improve symptom appraisal among symptomatic individuals in the general population to address the unmet need to shorten the prediagnosis interval. Many theories and models have been proposed to study the symptom appraisal process among patients with various chronic and acute health conditions,^{11 18–27} however, how these theories and models could be employed to improve symptom appraisal remains unclear. We, therefore, aimed to review approaches to improving symptom appraisal in the literature, and to develop a theoretical framework that could guide the development of approaches to improving symptom appraisal among individuals in the general population to facilitate early diagnosis.

Methods

We conducted a systematic literature search of existing approaches developed to improve symptom appraisal among individuals with any health conditions. We first performed preliminary searches in Medline using the concepts of symptom and appraisal, based on which the definitions of symptom and symptom appraisal for use in this study were developed, and search terms for the concepts of symptom, appraisal and patient education were refined (online supplemental file 1).^{11 12 18–20 22–31} We performed the final literature search with the refined search terms in the following six electronic databases: Medline, Web of Science, PsycINFO, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Scopus. We included all articles published from inception to 30 March 2021.

This systematic review was registered with the PROSPERO International prospective register of systematic reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was followed in the reporting (online supplemental file 2).³²

Inclusion and exclusion criteria

One main reviewer (the first author) screened the title and abstract of all articles identified from the final literature search, with any uncertainty resolved by discussion with the other authors. We examined the references of all review articles to identify relevant publications. We included articles for full text review if they met the following three criteria: (1) original articles in which approaches (or their components) to improving symptom appraisal were described, (2) approaches (or their components) aimed to improve the detection, interpretation or response to symptoms, and (3) approaches were developed for individuals with bodily changes/symptoms. We excluded articles in which approaches were developed to improve symptom appraisal among healthcare professionals such as medical trainees and nursing students.

Quality assessment

Quality assessment was conducted using the Joanna Briggs Institute (JBI) critical appraisal tools primarily by the first author, with any uncertainty resolved by discussion with the other authors.^{33 34} A raw score was calculated for each of the selected studies by dividing the number of positive responses by the total number of applicable statements in the JBI critical appraisal tools. High risk of bias was defined as a raw score of 49% or lower, moderate risk of bias was defined as a raw score between 50% and 69%, and low risk of bias was defined as a raw score of 70% or above.

Data extraction and synthesis

Data on study design, participants and the development, characteristics (type, format and components), and evaluation of approaches were extracted using a predefined data extraction form primarily by the first author, with any uncertainty resolved by discussion with the other authors. Due to the great heterogeneity in study design and outcome measures of the developed approaches, a narrative synthesis was performed.

Patient and public involvement

Patients and/or the public were not involved in the design, conduct, reporting or dissemination of this research.

Results

Study selection

Among the 19 046 records identified from the final literature search, 10 613 were screened the title and abstract after removing duplicates, 196 were assessed for eligibility and 112 were included in the full text review (figure 1). An additional 67 eligible records were identified from citation searching, yielding a total of 179 eligible publications from 160 unique studies.

Figure 1. PRISMA chart. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

After reviewing these 160 studies, we excluded 131 (81.9%) studies in which approaches comprised only provision of knowledge of symptoms/signs of a given health condition. We included the remaining 29 (18.1%) studies in which approaches comprised provision of both knowledge of symptoms/signs and additional components (such as demonstration and/or hands-on practice of self-examination and comparison of symptoms) to improve symptom appraisal in the synthesis (table 1). This was based on the consideration that provision of knowledge (of symptoms/signs) alone might not be sufficient to produce the desired behaviour (ie, detection, interpretation and response to symptoms),³⁵ and that we aimed to develop similar approaches to help individuals recognise and respond promptly to their symptoms/signs.

Table 1

Characteristics of studies included in the synthesis

Study	Health conditions	Type and format of approaches	Constructs of symptom appraisal addressed	Underlying theories/models
Cancer
Dine et al, 201159	BCLE	Education sessions	Detection (demonstration) and response	Nil
Brailey et al, 198636	Breast cancer	Education sessions and materials (film, pamphlet)	Detection (demonstration and hands-on practice)	PRECEDE Model65
Burgess et al, 200860	Breast cancer	Education sessions and materials (booklet with graphics and illustrations, photographs of symptoms)	Detection (demonstration) and response (role modelling)	SRT,74 TPB,66 Implementation Intentions81 and SCT67
Byrne and Robles-Rodriguez, 200961	Breast cancer	Education sessions and materials (pictures or illustrations)	Detection (demonstration and hands-on practice) and response	Nil
Craun and Deffenbacher, 198749	Breast cancer	Education sessions and materials (pamphlet)	Detection (demonstration and hands-on practice)	HBM70
Khokhar, 200950	Breast cancer	Education sessions and materials (video clip and pamphlet)	Detection (demonstration and hands-on practice)	Nil
McLendon et al, 198251	Breast cancer	Education sessions (one-to-one)	Detection (hands-on practice) and response	Nil
Shepherd and Mclnerney, 200752	Breast cancer	Education sessions and materials (multimedia: radio)	Detection (demonstration) and response	Orem’s Self Care Nursing Model82
Sørensen et al, 200537	Breast cancer	Education sessions (video)	Detection (demonstration)	Nil
Stratton et al, 199453	Breast cancer	Education sessions and materials (film and booklet)	Detection (demonstration)	Nil
Styrd, 198238	Breast cancer	Education sessions and materials (film and publication)	Detection (demonstration)	Nil
Luther et al, 198539	Breast and testicular cancer	Education sessions and materials (films)	Detection (demonstration)	Nil
Cornell et al, 201540	Melanoma	Education materials (photographs)	Interpretation (comparison)	Nil
Robertson et al, 201441	Melanoma	Education materials (video and images of skin lesions)	Interpretation (comparison)	Nil
Scott et al, 201242	Oral cancer	Education sessions and materials (leaflet)	Detection (hands-on practice) and response	SRT,18 75 SCT67
Brooks et al, 200154	Skin cancer	Education materials (pictures of skin lesions)	Interpretation (comparison)	Nil
Respiratory diseases
Butz et al, 200555	Asthma	Education sessions	Identification, interpretation (comparison) and response	MSM22
Colland et al, 200443	Asthma	Education sessions	Identification, interpretation (comparison) and response	Nil
Gardner, 201662	Asthma	Education sessions and materials (binder with large pictures)	Recognition, interpretation (comparison) and response	HBM70
Hendricson et al, 199644	Asthma	Education sessions and materials (flip cards with illustrations, videotape, pamphlet)	Recognition and response (role modelling)	SLT,78 SCT68
Brandt, 201363	COPD	Education sessions	Recognition, interpretation (comparison) and response	Collaborative Model for Self-Management of Chronic Disease83
Cardiovascular diseases
Davis et al, 201945	ACS	Education sessions and materials (pamphlet and pocket card)	Recognition, interpretation (comparison) and response	Nil
Raczynski et al, 199964	AMI	Education sessions and materials (flyers/brochures, posters, magnets and other “tokens”; video)	Recognition and response (role modelling)	SCT,69 SRT,76 CO,71 DIT,72 SMT73
Jurgens et al, 201346	HF	Education sessions and materials (booklet)	Detection, interpretation (comparison) and response	Theory of HF Self-Care,84 TUS,28 77 UIT,85–88 SRT75
Other health conditions
Hunt, 201556	Concussion	Education materials (video)	Detection, interpretation (comparison) and response	Nil
Bonovich, 199057	Labour	Education sessions and materials	Detection, interpretation (comparison) and response	Flanders’ Analysing Teaching Behaviour,79 Redman’s Principles of Patient Education80
Eriksen, 201047	Malaria	Education sessions	Detection, interpretation and response (role modelling)	Nil
Matin, 202048	Neonatal illness	Education apps/devices (audio, images of danger signs)	Detection, interpretation (comparison) and response	Nil
Ziadé et al, 202158	RA	Education materials (video)	Detection (demonstration)	Nil

ACS, acute coronary syndrome; AMI, acute myocardial infarction; BCLE, lymphedema secondary to breast cancer treatment; CO, community organisation theory; COPD, chronic obstructive pulmonary disease; DIT, diffusion of innovation theory; HBM, health belief model; HF, heart failure; MSM, model of symptom management; Nil, no theories/models were adopted; PRECEDE, predisposing, reinforcing, and enabling causes in educational diagnosis and evaluation; RA, rheumatoid arthritis; SCT, social cognitive theory; SLT, social learning theory; SMT, social marketing theory; SRT, self-regulation theory; TPB, theory of planned behaviour; TUS, theory of unpleasant symptoms; UIT, uncertainty in illness theory.

Of these 29 studies, 13 were categorised as having low risk of bias,^36–48 10 were categorised as having moderate risk of bias,^49–58 and 6 were unable to be assessed due to a lack of detailed evaluation of the developed approaches.^59–64 The raw scores of these studies were shown in online supplemental file 3. We included all 29 studies in the synthesis as our focus was the development instead of the evaluation of approaches.

Characteristics of approaches included in the synthesis

Of the 29 studies included in the synthesis, 16 focused on cancer,^{36–42 49–54 59–61} 5 on respiratory diseases,^{43 44 55 62 63} 3 on cardiovascular diseases^{45 46 64} and 1 each on other health conditions including concussion,⁵⁶ labour,⁵⁷ malaria,⁴⁷ neonatal illness⁴⁸ and RA.⁵⁸ Six were community-based studies engaging various parties (eg, educators and women leaders) in the communities and employing different outreach efforts (eg, flyers and radio advertisements),^{37 39 47 52 61 64} among which two involved training of both laypersons and health providers.^{47 64} Five studies reported only the development of approaches,^{59 60 62–64} while the remaining 24 reported both the development and evaluation of approaches using quantitative and/or qualitative measures (online supplemental file 4).^{36–58 61}

The most common type of approaches was a combination of education sessions and education materials (n=15), followed by education sessions alone (n=8), education materials alone (n=5), and education applications/devices (n=1) (table 2). The majority (n=18) of these approaches used both text and audio visual aids or multimedia to describe and illustrate symptoms/signs. All approaches comprised provision of knowledge of target symptoms/sign, 14 comprised demonstration and/or hands-on practice of symptom self-examination, 12 comprised comparison or target symptoms/signs with symptoms/signs of other health conditions and 3 comprised other components such as role modelling of the detection, interpretation and response to target symptoms/signs.

Table 2

Characteristics of approaches developed for various health conditions

	Cancer (n=16)	Respiratory diseases (n=5)	Cardiovascular diseases (n=3)	Other health conditions* (n=5)	Total (n=29)
Type of approaches, n (%)
Education sessions	4 (25.0)	3 (60.0)	0 (0.0)	1 (20.0)	8 (27.6)
Education materials	3 (18.8)	0 (0.0)	0 (0.0)	2 (40.0)	5 (17.2)
Education sessions and education materials	9 (56.3)	2 (40.0)	3 (100.0)	1 (20.0)	15 (51.7)
Education apps/devices	0 (0.0)	0 (0.0)	0 (0.0)	1 (20.0)	1 (3.5)
Format of approaches, n (%)
Text	4 (25.0)	3 (60.0)	2 (66.7)	2 (40.0)	11 (37.9)
Audio visual aids	11 (68.8)	2 (40.0)	1 (33.3)	3 (60.0)	17 (58.6)
Multimedia	1 (6.3)	0 (0.0)	0 (0.0)	0 (0.0)	1 (3.5)
Components of approaches, n (%)
Knowledge of symptoms/signs	16 (100.0)	5 (100.0)	3 (100.0)	5 (100.0)	29 (100.0)
Demonstration and/or hands-on practice of symptom self-examination	13 (81,3)	0 (0.0)	0 (0.0)	1 (20.0)	14 (48.3)
Symptom comparison	3 (18.8)	4 (80.0)	2 (66.7)	3 (60.0)	12 (41.4)
Other components: role modelling	0 (0.0)	1 (20.0)	1 (33.3)	1 (20.0)	3 (10.3)
Underlying theories/models adopted in the development of approaches, n (%)
No	11 (68.8)	1 (20.0)	1 (33.3)	4 (80.0)	17 (58.6)
Yes	5 (31.3)	4 (80.0)	2 (66.7)	1 (20.0)	12 (41.4)

*Other health conditions included concussion (n=1), labour (n=1), malaria (n=1), neonatal illness (n=1) and rheumatoid arthritis (n=1).

Theories/models adopted in the development of approaches

Despite the apparent similarity of components in the approaches, less than half (n=12) were developed based on theories/models and a variety of theories/models were adopted in the development of these approaches (table 2). The adopted theories/models could be grouped into four categories:

• Health behaviour theories/models, including Predisposing, Reinforcing and Enabling Causes in Educational Diagnosis and Evaluation Model,⁶⁵ Theory of Planned Behaviour (TPB),⁶⁶ Social Cognitive Theory (SCT),^67–69 Health Belief Model (HBM),⁷⁰ Community Organisation (CO),⁷¹ Diffusion of Innovations Theory (DIT)⁷² and Social Marketing Theory.⁷³

• Symptom appraisal theories/models, including Self-Regulation Theory (SRT),^{18 74–76} Model of Symptom Management²² and Theory of Unpleasant Symptoms.^{28 77}

• Educational theories/models, including Social Learning Theory,⁷⁸ Flanders’ Analysing Teaching Behaviour⁷⁹ and Redman’s Principles of Patient Education.⁸⁰

• Other theories/models, including Implementation Intentions,⁸¹ Orem’s Self Care Nursing Model,⁸² Collaborative Model for Self-Management of Chronic Disease,⁸³ Theory of Heart Failure Self-Care⁸⁴ and Uncertainty in Illness Theory.^85–88

The most common theories/models underlying the approaches were SCT and SRT, adopted in four studies each,^{42 44 46 60 64} among which three studies adopted both SCT and SRT.^{42 60 64} The second most common theory/model was HBM, adopted in two studies.^{49 62} The remaining theories/models were adopted in only one study.^{36 44 46 52 55 57 60 63 64}

Evaluation of the developed approaches

Evaluation of the developed approaches focused primarily on their effectiveness in the majority of these studies,^{36–43 45–58} while the reach, adoption and implementation of these approaches were evaluated in five studies,^{39 44 45 48 61} based on the Reach, Effectiveness, Adoption, Implementation and Maintenance framework.⁸⁹ The outcome measures included the following:

• Knowledge, attitudes and beliefs about the given health conditions and symptoms/signs (n=11).^{36 39 42 43 45 46 48 49 51 55 56}

• Skills, attitudes and practice of symptom self-examination via self-reporting (n=8),^{36–39 42 49–51} observation by examiners (n=3),^{48 52 53} or qualitative interview (n=1).⁵⁸

• Accuracy comparison of target symptoms/signs and those of other health conditions (n=4).^{40 41 54 57}

• Confidence and delay in help-seeking (n=3).^{42 46 48}

• Severity of health conditions (n=3).^{43 46 47}

• Satisfaction of educators (n=1)³⁹ and satisfaction of patients and caregivers via self-reporting (n=2)^{44 45} or qualitative interview (n=1).⁴⁸

• Implementation of approaches such as reviewing of education materials and appointment-making for clinical screening services (n=2).^{44 61}

Discussion

In this study, we reviewed existing approaches to improving symptom appraisal in the literature. Provision of symptom knowledge, self-examination and comparison as well as demonstration/illustration of symptom appraisal using role modelling were common approaches identified from the literature search. We found significant heterogeneity in whether theories/models were employed and the choice of theories/models employed in the development of these approaches. Only a small number of studies involving provision of both knowledge of symptoms/signs and other approaches were found in the literature search, highlighting the need for such studies with the goal of improving symptom appraisal and reducing prediagnosis interval among individuals in the general population.

Approaches that were developed in the vast majority (81.9%) of studies identified from the literature search comprised only provision of knowledge of symptoms/signs of a given health condition. While knowledge acquisition is a precondition for performing symptom appraisal (a given behaviour), knowledge alone does not lead to the desired behaviour (symptom appraisal).³⁵ For example, in the literature review by Teuschl and Brainin, a discrepancy was observed between the theoretical knowledge of and response to stroke symptoms, with only one-quarter to one-half of the patients who had been educated on stroke signs recognised their symptoms as stroke and in turn responding promptly.⁹⁰ As such, only approaches comprising both provision of the required knowledge and skills and additional components to enable personal, behavioural and environmental factors for symptom appraisal were included in the synthesis.

Theories and models present a systematic way of understanding complex issues (including symptom appraisal) by specifying the interrelationships among associated factors, which could provide a holistic framework for developing, implementing and evaluating interventions to address such issues.⁹¹ In addition to symptom appraisal theories/models, health behaviour theories/models were also commonly adopted in the development of approaches identified in the literature. Depending on the given health problem and its social context, health behaviour theories/models at different levels could be adopted.⁹¹ Since all of the three main constructs of symptom appraisal (ie, detection, interpretation and response to symptoms) are influenced by social environment such as access to health resources,^{92 93} health behaviour theories/models at interpersonal level (SCT) would be more appropriate for use in the context of symptom appraisal and was thus adopted more frequently compared with theories/models at individual/intrapersonal (eg, HBM and TPB) or community level (eg, CO and DIT).^{66–72 78} Health behaviour theories/models at interpersonal level provide the psychosocial mechanisms through which personal cognitive, behavioural and environmental factors interactively influence a given behaviour, while theories/models at individual/intrapersonal level do not address the environment that the person and behaviour interact in and theories/models at community level focus more on the engagement of communities.^{66–72 78} Multiple theories and models that complement each other are often adopted to guide the development of different components of a given approach. This was seen in half of the studies in which theories/models were adopted.^{42 44 46 57 60 64} Of note, health behaviour and symptom appraisal theories/models were adopted together in three of the four studies where they were used.^{42 60 64}

Building on these studies, we propose an integrated conceptual framework from the major concepts of SCT (reciprocal determinism, behavioural capacity, expectations, self-efficacy, observational learning and reinforcements) and main constructs of symptom appraisal (figure 2), in which approaches were proposed based on SCT to improve symptom appraisal.^{11 67 68} Reciprocal determinism, the reciprocal interaction of person, environment and behaviour, highlights the importance of a multipronged approach to enhance not only a given behaviour (behavioural capability and reinforcements) but also its associated personal (self-efficacy and expectations) and environmental (observational learning and social support) influences (table 3). To enhance the behavioural capacity to perform symptom appraisal, one must possess the knowledge of the target symptoms/signs (eg, through sight, touch, hearing and scent/smell) and the skills of how to detect, interpret and respond to the target symptoms/signs. This could be achieved through provision of essential knowledge of target symptoms/signs (symptom knowledge), demonstration of symptom self-examination, illustration of differences between target symptom/signs and symptoms/signs of other health conditions (symptom comparison), and instruction on actions to take on detection of target symptoms/signs (symptom response). Expectations, the anticipated consequences of symptom appraisal, could be enhanced by demonstration of positive outcomes of symptom appraisal, or more specifically, prompt symptom detection and help-seeking. The positive outcomes of symptom appraisal could also work as reinforcements of symptom appraisal behaviour. Self-efficacy, the confidence of performing symptom appraisal, could be increased by adopting various formats such as text, photo and video to enhance the knowledge and skills (behavioural capacity) required for symptom appraisal and by demonstrating symptom appraisal, namely symptom self-examination, comparison and response using role models, the latter could enhance symptom appraisal through observational learning.

Table 3

Proposed approaches to improving symptom appraisal

Concepts of the social cognitive theory	Definition of the concepts	Approaches to improving symptom appraisal in screening tools
Reciprocal determinism	Dynamic and reciprocal interaction of person, environment and behaviour	Provision of knowledge and skills (person and behaviour) and supportive environment required for symptom appraisal, for example, social support
Behavioural capacity	Ability (knowledge and skills) to perform a behaviour	Provision of symptom knowledge (sight and touch etc)
		Demonstration of symptom self-examination (sight and touch etc)
		Illustration of symptom comparison: differences between target symptoms/signs and symptoms/signs of other conditions (sight and touch etc)
		Instructions on symptom response, namely actions to take upon symptom detection
Expectations	Anticipated consequences of a behaviour	Demonstration of positive outcomes of prompt symptom detection and help-seeking
Self-efficacy	Confidence in one’s ability to perform a behaviour	Adoption of various formats such as text, photo and video to enhance symptom knowledge, self-examination, comparison, and response
		Demonstration of symptom self-examination, comparison and response using role models
Observational learning	Learning through observation for example, modelling of behaviours	Demonstration of symptom self-examination, comparison and response using role models
Reinforcements	Responses to a behaviour that affect the likelihood of reoccurrence	Demonstration of positive outcomes of prompt symptom detection and help-seeking

Figure 2. Proposed framework for improving symptom appraisal dashed boxes and arrows: concepts from Bandura’s social cognitive theory, dotted boxes and arrows: approaches to improving knowledge, skills, attitudes and beliefs about symptom appraisal using various formats including text, photos and videos, solid boxes and arrows: constructs from Whitaker’s synthesis of symptom appraisal models. The up down arrows denote interacting relationship between different components.

The proposed framework and approaches could be incorporated into the development of self-administered screening tools (online supplemental file 5), which are cost-effective in facilitating early disease identification in the general population.⁹⁴ Many existing screening tools, however, might be too challenging for individuals with lower health literacy to answer as they often assess only the presence of target symptoms/signs of a given health condition without any explanations of what target symptoms/signs are and how these might look, feel, etc. While providing a description/explanation of target symptoms/signs could, to some extent, aid comprehension and improve the accuracy of self-reporting on screening tools, many symptoms/signs cannot be easily explained using text and would require illustrations such as photos and videos. For example, the three phases of colour changes in Raynaud’s phenomenon, a common symptom seen among patients with ARDs, could be illustrated more clearly in the form of video instead of text. Such illustrations could prompt symptomatic individuals to notice the deviations from normality and enhance symptom appraisal by providing the context for interpretation, extralingual information, clarifying examples and redundancy to aid comprehension of the text.⁹⁵ In the literature review by Levie and Lentz, increased understanding was observed in 98% of the experiments using different illustrations.⁹⁶ Furthermore, other approaches such as demonstration of symptom self-examination and response using role models could be better illustrated using photos and videos.

There are three main limitations in this study. First, only free-text search was conducted in Web of Science and Scopus due to a lack of controlled vocabularies in these two databases. However, in consultation with a medical librarian with expertise in literature searches, a list of comprehensive free-text search terms were developed based on preliminary literature searches and both controlled vocabulary search and free-text search were used in other databases (Medline, PsycINFO, Embase and CINAHL), which would be sufficient to identify most of the important articles in the literature. Second, five reports identified in the literature search were unable to be retrieved, which might contain theories/models and approaches that differ from those reviewed in this study. However, based on their title and abstract, these reports comprise mainly self-examination of symptoms/signs of breast, skin and testicular cancer and macular degeneration, and similar approaches had been included in our review and synthesis. Finally, the proposed framework is conceptual and requires empirical data to support it. Qualitative interviews with patients with ARDs are planned in our future work to further validate the framework by understanding the experience of symptom appraisal and approaches that could help the patients detect, interpret and take prompt actions in response to symptoms/signs. A screening tool comprising approaches to improving symptom appraisal will then be developed. Furthermore, the proposed framework and approaches target mainly knowledge, skills, attitudes and beliefs about symptom appraisal (behaviour) among symptomatic individuals (person). The environment with which person and behaviour interact such as cultural beliefs, social support, healthcare system and healthcare professionals also plays an important role in promoting or inhibiting symptom appraisal among these individuals. These environmental factors, however, could not be easily incorporated into screening tools but rather into large-scale public health screening programmes, which is a potential focus for our future work.

Conclusion

Symptom appraisal is an essential process in a patient’s journey that can be targeted to facilitate early diagnosis but is largely unstudied. Building on the literature, we propose a theoretical framework and approaches to improving symptom appraisal. This could facilitate early identification of a variety of health conditions in the general population.

We would like to thank Ms Suei-Nee Wong, a senior librarian in the medical library of the National University Singapore, for her assistance in the development of literature search strategy.

Data availability statement

Data are available on reasonable request. All data relevant to the study are available on reasonable request to the corresponding author.

Ethics statements

Patient consent for publication

Not applicable.

Ethics approval

Not applicable.

Footnote

Contributors LX, AHLL, TCL, DRK and JT designed the search. LX conducted the search, extracted and analysed the data, and drafted the manuscript. SY, AHLL, YYL, WF, TCL, DRK and JT contributed to the interpretation of the data and editing of the manuscript. All authors read and approved the final version of the manuscript. JT is the guarantor for this work.

Funding This work was supported by the SingHealth Duke-NUS Academic Medicine Research Grant (grant reference: AM/HSR015/2021) and Goh Cheng Liang Rheumatology ARISE (Advancing Research and Innovation with Synergistic Expertise) Programme Fund (funding reference: N/A).

Disclaimer The funders had no role in the design of the study and collection, analysis, and interpretation of data and in writing of this manuscript.

Competing interests None declared.

Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

Provenance and peer review Not commissioned; externally peer reviewed.

Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

References

¹ Zhao SS, Pittam B, Harrison NL, et al. Diagnostic delay in axial spondyloarthritis: a systematic review and meta-analysis. Rheumatology 2021; 60: 1620–8. doi:10.1093/rheumatology/keaa807 http://www.ncbi.nlm.nih.gov/pubmed/33428758

² Lauritzen BB, Jensen JS, Grønhøj C, et al. Impact of delay in diagnosis and treatment-initiation on disease stage and survival in oral cavity cancer: a systematic review. Acta Oncol 2021; 60: 1083–90. doi:10.1080/0284186X.2021.1931712 http://www.ncbi.nlm.nih.gov/pubmed/34043480

³ Qu LG, Brand NR, Chao A, et al. Interventions addressing barriers to delayed cancer diagnosis in low- and middle-income countries: a systematic review. Oncologist 2020; 25: e1382–95. doi:10.1634/theoncologist.2019-0804 http://www.ncbi.nlm.nih.gov/pubmed/32125732

⁴ Bello S, Afolabi RF, Ajayi DT, et al. Empirical evidence of delays in diagnosis and treatment of pulmonary tuberculosis: systematic review and meta-regression analysis. BMC Public Health 2019; 19: 820. doi:10.1186/s12889-019-7026-4 http://www.ncbi.nlm.nih.gov/pubmed/31238906

⁵ Prior JA, Ranjbar H, Belcher J, et al. Diagnostic delay for giant cell arteritis - a systematic review and meta-analysis. BMC Med 2017; 15: 120. doi:10.1186/s12916-017-0871-z http://www.ncbi.nlm.nih.gov/pubmed/28655311

⁶ Jovaní V, Blasco-Blasco M, Ruiz-Cantero MT, et al. Understanding how the diagnostic delay of spondyloarthritis differs between women and men: a systematic review and Metaanalysis. J Rheumatol 2017; 44: 174–83. doi:10.3899/jrheum.160825 http://www.ncbi.nlm.nih.gov/pubmed/27980009

⁷ Getnet F, Demissie M, Assefa N, et al. Delay in diagnosis of pulmonary tuberculosis in low-and middle-income settings: systematic review and meta-analysis. BMC Pulm Med 2017; 17: 202. doi:10.1186/s12890-017-0551-y http://www.ncbi.nlm.nih.gov/pubmed/29237451

⁸ Brasme J-F, Morfouace M, Grill J, et al. Delays in diagnosis of paediatric cancers: a systematic review and comparison with expert testimony in lawsuits. Lancet Oncol 2012; 13: e445–59. doi:10.1016/S1470-2045(12)70361-3 http://www.ncbi.nlm.nih.gov/pubmed/23026830

⁹ Andersen BL, Cacioppo JT. Delay in seeking a cancer diagnosis: delay stages and psychophysiological comparison processes. Br J Soc Psychol 1995; 34 (Pt 1): 33–52. doi:10.1111/j.2044-8309.1995.tb01047.x 7735731

¹⁰ Barhamain AS, Magliah RF, Shaheen MH, et al. The journey of rheumatoid arthritis patients: a review of reported lag times from the onset of symptoms. Open Access Rheumatol 2017; 9: 139–50. doi:10.2147/OARRR.S138830 http://www.ncbi.nlm.nih.gov/pubmed/28814904

¹¹ Whitaker KL, Scott SE, Wardle J. Applying symptom appraisal models to understand sociodemographic differences in responses to possible cancer symptoms: a research agenda. Br J Cancer 2015; 112 Suppl (1): S27–34. doi:10.1038/bjc.2015.39 http://www.ncbi.nlm.nih.gov/pubmed/25734385

¹² Robbins JM, Kirmayer LJ. Attributions of common somatic symptoms. Psychol Med 1991; 21: 1029–45. doi:10.1017/S0033291700030026 http://www.ncbi.nlm.nih.gov/pubmed/1780396

¹³ Simons G, Mason A, Falahee M, et al. Qualitative exploration of illness perceptions of rheumatoid arthritis in the general public. Musculoskeletal Care 2017; 15: 13–22. doi:10.1002/msc.1135 http://www.ncbi.nlm.nih.gov/pubmed/26833593

¹⁴ Stack RJ, Shaw K, Mallen C, et al. Delays in help seeking at the onset of the symptoms of rheumatoid arthritis: a systematic synthesis of qualitative literature. Ann Rheum Dis 2012; 71: 493–7. doi:10.1136/ard.2011.155416 http://www.ncbi.nlm.nih.gov/pubmed/22121128

¹⁵ Xiang L, Low AHL, Leung YY, et al. Interval between symptom onset and diagnosis among patients with autoimmune rheumatic diseases in a multi-ethnic Asian population. Int J Rheum Dis 2021; 24: 1061–70. doi:10.1111/1756-185X.14165 http://www.ncbi.nlm.nih.gov/pubmed/34232556

¹⁶ Petrova D, Okan Y, Salamanca-Fernández E, et al. Psychological factors related to time to help-seeking for cancer symptoms: a meta-analysis across cancer sites. Health Psychol Rev 2020; 14: 245–68. doi:10.1080/17437199.2019.1641425 http://www.ncbi.nlm.nih.gov/pubmed/31284829

¹⁷ Macdonald S, Macleod U, Campbell NC, et al. Systematic review of factors influencing patient and practitioner delay in diagnosis of upper gastrointestinal cancer. Br J Cancer 2006; 94: 1272–80. doi:10.1038/sj.bjc.6603089 http://www.ncbi.nlm.nih.gov/pubmed/16622459

¹⁸ Leventhal H, Meyer D, Nerenz D. The common sense representation of illness danger. In: Contributions to medical psychology. Pergamon Press, 1980: 7–30.

¹⁹ Leventhal H, Benyamini Y, Brownlee S. Illness Representations: Theoretical Foundations. In: Petrie KJ, Weinman J, eds. Perceptions of health and illness: current research and applications. Harwood Academic Publishers, 1997.

²⁰ Sorofman B, Tripp-Reimer T, Lauer GM, et al. Symptom self-care. Holist Nurs Pract 1990; 4: 45–55. doi:10.1097/00004650-199002000-00009 http://www.ncbi.nlm.nih.gov/pubmed/2405000

²¹ Cioffi D. Beyond attentional strategies: cognitive-perceptual model of somatic interpretation. Psychol Bull 1991; 109: 25–41. doi:10.1037/0033-2909.109.1.25 http://www.ncbi.nlm.nih.gov/pubmed/2006227

²² The University of California San Francisco School of Nursing Symptom Management Faculty Group. A model for symptom management. Image 1994; 26: 272–6. doi:10.1111/j.1547-5069.1994.tb00333.x

²³ Dodd M, Janson S, Facione N, et al. Advancing the science of symptom management. J Adv Nurs 2001; 33: 668–76. doi:10.1046/j.1365-2648.2001.01697.x http://www.ncbi.nlm.nih.gov/pubmed/11298204

²⁴ Teel CS, Meek P, McNamara AM, et al. Perspectives unifying symptom interpretation. Image J Nurs Sch 1997; 29: 175–81. doi:10.1111/j.1547-5069.1997.tb01553.x http://www.ncbi.nlm.nih.gov/pubmed/9212516

²⁵ van Wijk CM, Kolk AM. Sex differences in physical symptoms: the contribution of symptom perception theory. Soc Sci Med 1997; 45: 231–46. doi:10.1016/S0277-9536(96)00340-1 http://www.ncbi.nlm.nih.gov/pubmed/9225411

²⁶ Henly SJ, Kallas KD, Klatt CM, et al. The notion of time in symptom experiences. Nurs Res 2003; 52: 410–7. doi:10.1097/00006199-200311000-00009 http://www.ncbi.nlm.nih.gov/pubmed/14639088

²⁷ Petersen S, van den Berg RA, Janssens T, et al. Illness and symptom perception: a theoretical approach towards an integrative measurement model. Clin Psychol Rev 2011; 31: 428–39. doi:10.1016/j.cpr.2010.11.002 http://www.ncbi.nlm.nih.gov/pubmed/21146271

²⁸ Lenz ER, Pugh LC, Milligan RA, et al. The middle-range theory of unpleasant symptoms: an update. ANS Adv Nurs Sci 1997; 19: 14–27. doi:10.1097/00012272-199703000-00003 http://www.ncbi.nlm.nih.gov/pubmed/9055027

²⁹ Armstrong TS. Symptoms experience: a concept analysis. Oncol Nurs Forum 2003; 30: 601–6. doi:10.1188/03.ONF.601-606 http://www.ncbi.nlm.nih.gov/pubmed/12861321

³⁰ Kolk AM, Hanewald GJFP, Schagen S, et al. A symptom perception approach to common physical symptoms. Soc Sci Med 2003; 57: 2343–54. doi:10.1016/S0277-9536(02)00451-3 http://www.ncbi.nlm.nih.gov/pubmed/14572841

³¹ Posey AD. Symptom perception: a concept exploration. Nurs Forum 2006; 41: 113–24. doi:10.1111/j.1744-6198.2006.00047.x http://www.ncbi.nlm.nih.gov/pubmed/16879146

³² Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021; 372: n71. doi:10.1136/bmj.n71 http://www.ncbi.nlm.nih.gov/pubmed/33782057

³³ Tufanaru C, Munn Z, Aromataris E. Chapter 3: Systematic reviews of effectiveness. In: JBI manual for evidence synthesis. In: JBI, 2020. https://synthesismanual.jbi.global

³⁴ Lockwood C, Munn Z, Porritt K. Qualitative research synthesis: methodological guidance for systematic reviewers utilizing meta-aggregation. Int J Evid Based Healthc 2015; 13: 179–87. doi:10.1097/XEB.0000000000000062 http://www.ncbi.nlm.nih.gov/pubmed/26262565

³⁵ Bandura A. Health promotion by social cognitive means. Health Educ Behav 2004; 31: 143–64. doi:10.1177/1090198104263660 http://www.ncbi.nlm.nih.gov/pubmed/15090118

³⁶ Brailey LJ. Effects of health teaching in the workplace on women's knowledge, beliefs, and practices regarding breast self-examination. Res Nurs Health 1986; 9: 223–31. doi:10.1002/nur.4770090307 http://www.ncbi.nlm.nih.gov/pubmed/3639537

³⁷ Sørensen J, Hertz A, Gudex C. Evaluation of a Danish teaching program in breast self-examination. Cancer Nurs 2005; 28: 141–7. http://www.ncbi.nlm.nih.gov/pubmed/15815184

³⁸ Styrd AM. A breast self-examination program in an occupational health setting. Occup Health Nurs 1982; 30: 33–5. doi:10.1177/216507998203000406 http://www.ncbi.nlm.nih.gov/pubmed/6917967

³⁹ Luther SL, Sroka S, Goormastic M, et al. Teaching breast and testicular self-exams: evaluation of a high school curriculum pilot project. Health Educ 1985; 16: 40–3. doi:10.1080/00970050.1985.10615817 http://www.ncbi.nlm.nih.gov/pubmed/3939881

⁴⁰ Cornell E, Robertson K, McIntosh RD, et al. Viewing exemplars of melanomas and benign mimics of melanoma modestly improves diagnostic skills in comparison with the ABCD method and other image-based methods for lay identification of melanoma. Acta Derm Venereol 2015; 95: 681–5. doi:10.2340/00015555-2058 http://www.ncbi.nlm.nih.gov/pubmed/25633058

⁴¹ Robertson K, McIntosh RD, Bradley-Scott C, et al. Image training, using random images of melanoma, performs as well as the ABC(D) criteria in enabling novices to distinguish between melanoma and mimics of melanoma. Acta Derm Venereol 2014; 94: 265–70. doi:10.2340/00015555-1733 http://www.ncbi.nlm.nih.gov/pubmed/24212235

⁴² Scott SE, Khwaja M, Low EL, et al. A randomised controlled trial of a pilot intervention to encourage early presentation of oral cancer in high risk groups. Patient Educ Couns 2012; 88: 241–8. doi:10.1016/j.pec.2012.03.015 http://www.ncbi.nlm.nih.gov/pubmed/22521755

⁴³ Colland VT, van Essen-Zandvliet LEM, Lans C, et al. Poor adherence to self-medication instructions in children with asthma and their parents. Patient Educ Couns 2004; 55: 416–21. doi:10.1016/j.pec.2003.04.010 http://www.ncbi.nlm.nih.gov/pubmed/15582348

⁴⁴ Hendricson WD, Wood PR, Hidalgo HA, et al. Implementation of individualized patient education for Hispanic children with asthma. Patient Educ Couns 1996; 29: 155–65. doi:10.1016/0738-3991(96)00861-0 http://www.ncbi.nlm.nih.gov/pubmed/9006232

⁴⁵ Davis LL, McCoy TP, Educational A. An educational and Skill-Building intervention to improve symptom recognition and interpretation in women with acute coronary syndrome: a pilot study. Dimens Crit Care Nurs 2019; 38: 29–37. doi:10.1097/DCC.0000000000000329 http://www.ncbi.nlm.nih.gov/pubmed/30499790

⁴⁶ Jurgens CY, Lee CS, Reitano JM, et al. Heart failure symptom monitoring and response training. Heart Lung 2013; 42: 273–80. doi:10.1016/j.hrtlng.2013.03.005 http://www.ncbi.nlm.nih.gov/pubmed/23623564

⁴⁷ Eriksen J, Mujinja P, Warsame M, et al. Effectiveness of a community intervention on malaria in rural Tanzania - a randomised controlled trial. Afr Health Sci 2010; 10: 332–40. http://www.ncbi.nlm.nih.gov/pubmed/21416034

⁴⁸ Matin SB, Wallingford A, Xu S, et al. Feasibility of a mobile health tool for mothers to identify neonatal illness in rural Uganda: acceptability study. JMIR Mhealth Uhealth 2020; 8: e16426. doi:10.2196/16426 http://www.ncbi.nlm.nih.gov/pubmed/32130174

⁴⁹ Craun AM, Deffenbacher JL. The effects of information, behavioral rehearsal, and prompting on breast self-exams. J Behav Med 1987; 10: 351–65. doi:10.1007/BF00846475 http://www.ncbi.nlm.nih.gov/pubmed/3669070

⁵⁰ Khokhar A, messages Stext. Short text messages (SMS) as a reminder system for making working women from Delhi breast aware. Asian Pac J Cancer Prev 2009; 10: 319–22. http://www.ncbi.nlm.nih.gov/pubmed/19537904

⁵¹ McLendon MS, Fulk CH, Starnes DC. Effectiveness of breast self-examination teaching to women of low socioeconomic class. JOGN Nurs 1982; 11: 7–10. doi:10.1111/j.1552-6909.1982.tb00995.x http://www.ncbi.nlm.nih.gov/pubmed/6919664

⁵² Shepherd JHEE, Mclnerney PA. Knowledge of breast self-examination in women in Sierra Leone. Curationis 2007; 30: 38–44. doi:10.4102/curationis.v30i4.1115 http://www.ncbi.nlm.nih.gov/pubmed/18402419

⁵³ Stratton BF, Nicholson ME, Olsen LK, et al. Breast self-examination proficiency: attitudinal, demographic, and behavioral characteristics. J Womens Health 1994; 3: 185–95. doi:10.1089/jwh.1994.3.185

⁵⁴ Brooks A, Predebon J, van der Zwan R. Perceptual strategies to improve skin cancer discriminations in naive observers. Public Health 2001; 115: 139–45. doi:10.1016/S0033-3506(01)00433-4 http://www.ncbi.nlm.nih.gov/pubmed/11406780

⁵⁵ Butz AM, Syron L, Johnson B, et al. Home-Based asthma self-management education for inner City children. Public Health Nurs 2005; 22: 189–99. doi:10.1111/j.0737-1209.2005.220302.x http://www.ncbi.nlm.nih.gov/pubmed/15982192

⁵⁶ Hunt TN. Video educational intervention improves reporting of concussion and symptom recognition. Athletic Training Education Journal 2015; 10: 65–74. doi:10.4085/100165

⁵⁷ Bonovich L. Recognizing the onset of labor. J Obstet Gynecol Neonatal Nurs 1990; 19: 141–5. doi:10.1111/j.1552-6909.1990.tb01632.x http://www.ncbi.nlm.nih.gov/pubmed/2319363

⁵⁸ Ziadé N, Saad S, Al Mashaleh M, et al. Perceptions of patients with rheumatoid arthritis about self-assessment of disease activity after watching an educational video: a qualitative pilot study from the AUTO-DAS in middle Eastern Arab countries project. Rheumatol Int 2021; 41: 733–40. doi:10.1007/s00296-021-04799-2 http://www.ncbi.nlm.nih.gov/pubmed/33547917

⁵⁹ Dine JL, Austin MKS, Armer JM. Nursing education on lymphedema self-management and self-monitoring in a South African oncology clinic. J Cult Divers 2011; 18: 126–8. http://www.ncbi.nlm.nih.gov/pubmed/22288209

⁶⁰ Burgess CC, Bish AM, Hunter HS, et al. Promoting early presentation of breast cancer: development of a psycho-educational intervention. Chronic Illn 2008; 4: 13–27. doi:10.1177/1742395307084404 http://www.ncbi.nlm.nih.gov/pubmed/18322026

⁶¹ Byrne S, Robles-Rodriguez E. Educational parties as a strategy to promote breast health awareness and screening in underserved female populations. Oncol Nurs Forum 2009; 36: 145–8. doi:10.1188/09.ONF.145-148 http://www.ncbi.nlm.nih.gov/pubmed/19273403

⁶² Gardner LE. Advanced practitioner provided pre-hospital discharge asthma education. Walden University, 2016.

⁶³ Brandt CL. Study of older adults' use of self-regulation for COPD self-management informs an evidence-based patient teaching plan. Rehabil Nurs 2013; 38: 11–23. doi:10.1002/rnj.56 http://www.ncbi.nlm.nih.gov/pubmed/23365001

⁶⁴ Raczynski JM, Finnegan JR, Zapka JG, et al. React theory-based intervention to reduce treatment-seeking delay for acute myocardial infarction. rapid early action for coronary treatment. Am J Prev Med 1999; 16: 325–34. doi:10.1016/s0749-3797(99)00023-9 http://www.ncbi.nlm.nih.gov/pubmed/10493291

⁶⁵ Green LW, Kreuter MW, Deeds S, et al. Health education planning: a diagnostic approach. Mayfield Publishing Company, 1980.

⁶⁶ Ajzen I. The theory of planned behavior. Organizational Behavior and Human Decision Processes 1991; 50: 179–211.

⁶⁷ Bandura A. Self-Efficacy: toward a unifying theory of behavioral change. Psychol Rev 1977; 84: 191–215. doi:10.1037//0033-295x.84.2.191 http://www.ncbi.nlm.nih.gov/pubmed/847061

⁶⁸ Bandura A. Social foundations of thought and action: a social cognitive theory. Prentice-Hall, Inc, 1986.

⁶⁹ Perry CL, Baranowski T, Parcel GS. How individuals, environments, and health behavior interact: Social Cognitive Theory. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research, and practice. San Francisco, CA: Jossey-Bass, 1990.

⁷⁰ Rosenstock IM. Historical origins of the health belief model. Health Educ Monogr 1974; 2: 328–35. doi:10.1177/109019817400200403

⁷¹ Bracht N. Health promotion at the community level. Thousand Oaks, CA, US: Sage Publications, Inc, 1990.

⁷² Rogers EM. Diffusion of innovations. New York; London: Free Press; Collier Macmillan, 1983.

⁷³ Novelli W. Applying social marketing to health promotion and disease prevention. In: Glanz K, Lewis FM, Rimer BK, eds. Health behavior and health education: theory, research and practice. San Francisco, CA: Jossey-Bass, 1990.

⁷⁴ Leventhal H, Nerenz D, Steele D. Illness representations and coping with health threats. In: Baum A, Taylor SE, Singer J, eds. Handbook of psychology and health: social psychological aspects of health, 1984.: 219–52 p..

⁷⁵ Cameron LD, Leventhal H. The self-regulation of health and illness behaviour. New York, NY, US: Routledge, 2003.

⁷⁶ Cameron L, Leventhal EA, Leventhal H. Emotional and behavioral processes. In: Johnston M, Wallace L, eds. Stress and medical procedures. New York, NY: Pergamon, 1993: 7–30.

⁷⁷ Lenz ER, Suppe F, Gift AG, et al. Collaborative development of middle-range nursing theories: toward a theory of unpleasant symptoms. ANS Adv Nurs Sci 1995; 17: 1–13. doi:10.1097/00012272-199503000-00003 http://www.ncbi.nlm.nih.gov/pubmed/7778887

⁷⁸ Parcel GS, Baranowski T. Social learning theory and health education. Health Educ 1981; 12: 14–18. doi:10.1080/00970050.1981.10618149 http://www.ncbi.nlm.nih.gov/pubmed/6792124

⁷⁹ Flanders NA, behavior Ateaching. Reading, mass, Addison. Wesley Pub. Co, 1970.

⁸⁰ Redman BK. The process of patient education. C.V. Mosby, 1984.

⁸¹ Gollwitzer PM. Goal achievement: the role of intentions. European Review of Social Psychology 1993; 4: 141–85.

⁸² Orem DE. Nursing: concepts of practice. McGraw-Hill, 1980.

⁸³ Brandt CL. Description of the self-regulation process used by persons with chronic lung disease and its relationship to health-related outcomes. University of Minnesota, 2005.

⁸⁴ Riegel B, Dickson VV. A situation-specific theory of heart failure self-care. J Cardiovasc Nurs 2008; 23: 190–6. doi:10.1097/01.JCN.0000305091.35259.85 http://www.ncbi.nlm.nih.gov/pubmed/18437059

⁸⁵ Mishel MH. The measurement of uncertainty in illness. Nurs Res 1981; 30: 258???263–63. doi:10.1097/00006199-198109000-00002 http://www.ncbi.nlm.nih.gov/pubmed/6912987

⁸⁶ Mishel MH. Perceived uncertainty and stress in illness. Res Nurs Health 1984; 7: 163–71. doi:10.1002/nur.4770070304 http://www.ncbi.nlm.nih.gov/pubmed/6567948

⁸⁷ Mishel MH. Uncertainty in illness. Image J Nurs Sch 1988; 20: 225–32. doi:10.1111/j.1547-5069.1988.tb00082.x http://www.ncbi.nlm.nih.gov/pubmed/3203947

⁸⁸ Mishel MH. Reconceptualization of the uncertainty in illness theory. Image J Nurs Sch 1990; 22: 256–62. doi:10.1111/j.1547-5069.1990.tb00225.x http://www.ncbi.nlm.nih.gov/pubmed/2292449

⁸⁹ Glasgow RE, Vogt TM, Boles SM. Evaluating the public health impact of health promotion interventions: the RE-AIM framework. Am J Public Health 1999; 89: 1322–7. doi:10.2105/AJPH.89.9.1322 http://www.ncbi.nlm.nih.gov/pubmed/10474547

⁹⁰ Teuschl Y, Brainin M. Stroke education: discrepancies among factors influencing prehospital delay and stroke knowledge. Int J Stroke 2010; 5: 187–208. doi:10.1111/j.1747-4949.2010.00428.x http://www.ncbi.nlm.nih.gov/pubmed/20536616

⁹¹ Glanz K, Rimer BK, Viswanath K. Research and practice. Wiley, 2015.

⁹² Dingwall R. Aspects of illness. Ashgate, 2001.

⁹³ Alonzo AA. Everyday illness behavior: a situational approach to health status deviations. Soc Sci Med 1979; 13A: 397–404. http://www.ncbi.nlm.nih.gov/pubmed/572993

⁹⁴ Villeneuve E, Nam JL, Bell MJ, et al. A systematic literature review of strategies promoting early referral and reducing delays in the diagnosis and management of inflammatory arthritis. Ann Rheum Dis 2013; 72: 13–22. doi:10.1136/annrheumdis-2011-201063 http://www.ncbi.nlm.nih.gov/pubmed/22532640

⁹⁵ Murray J, Williams B. The role of images on illness behaviour: interdisciplinary theory, evidence, and ideas. Psychol Rep 2021; 124: 0033294120945602: 2475. doi:10.1177/0033294120945602 32757718

⁹⁶ Levie WH, Lentz R. Effects of text illustrations: a review of research. ECTJ 1982; 30: 195–232. doi:10.1007/BF02765184