COVID-19 Associated Mucormycosis and Risk Factors: A Case-Control Study from Turkey

Headnote

Abstract

Background: Mucormycosis, a fatal fungal infection, has increased during the COVID-19 pandemic and posed significant challenges for clinicians.

Objectives: Our research focused on identifying the clinical traits of patients with COVID-19-associated mucormycosis (CAM), comparing them with a control group, and identifying risk factors for the development of CAM.

Methods: Our study was conducted on 39 CAM patients and 78 control patients from September 2020 to October 2022 at a tertiary education center and regional hospital. The control group was selected blindly in a 1:2 ratio among patients who did not develop mucormycosis, were hospitalized due to COVID-19, and were either discharged or deceased. The control group was matched to the case group regarding age and hospitalization date. To test potential risk factors for CAM, we performed a binary logistic regression analysis. The variables included in the multivariate binary logistic regression model were gender, diabetes, cumulative steroid dose (dexamethasone equivalent), duration of steroid treatment, and tocilizumab/anakinra treatment.

Results: In our study, 39 patients were diagnosed with CAM. The average age of the patients was 66 ± 11.5 years. Of the patients, 54.7% (n = 64) were male, with a statistically significantly higher proportion of men in the CAM group (74.4% vs. 44.9%, P = 0.003). The diabetes rate was 51.3% (n = 60) among all patients, and it was higher in the CAM group (69.2% vs. 42.3%, P = 0.006). Regarding in-hospital mortality, the rate was higher in the CAM group (56.4% vs. 14.1%, P < 0.001). The median length of stay in the hospital was 37 days for the CAM group and 10 days for the control group (P < 0.001). The cumulative steroid dose was elevated in the CAM group compared to the control group (191 ± 61.4 mg vs. 117 ± 69.8 mg, P < 0.001). The duration of steroid treatment was 16.5 ± 6.2 days in the CAM group, compared to 9.8 ± 4.7 days in the control group (P < 0.001). Among CAM cases, paranasal involvement was the most common (56.4%), followed by rhino-orbital involvement (33.3%). In binary logistic regression analysis, male gender (OR, 3.9; 95% CI, 1.4 – 11.3), diabetes mellitus (OR, 4.4; 95% CI, 1.5 – 12.4), more than ten days of steroid use (OR, 5.5; 95% CI, 1.3 – 22.4), and tocilizumab/anakinra use (OR, 0.23; 95% CI, 0.06 – 0.8) were identified as risk factors for the development of CAM (p values 0.011, 0.005, 0.019, and 0.020, respectively).

Conclusions: Male gender, diabetes mellitus, and steroid use for more than ten days were identified as positive risk factors, while tocilizumab/anakinra use was identified as a negative risk factor for the development of CAM.

Keywords: Mucormycosis, COVID-19, Risk Factors

1. Background

On March 11, 2020, SARS-CoV-2 triggered a pandemic known as COVID-19, which was first identified in Wuhan, China, approximately two months earlier. Subsequently, fungal co-infections such as aspergillosis, candidiasis, and mucormycosis began to appear, especially in intensive care patients. Mucormycosis, in particular, was increasingly detected during the pandemic, with the initial case of COVID-19-associated mucormycosis (CAM) reported in Chile. These cases began to be increasingly reported, especially in India, in early 2021 (1). The sudden increase in mucormycosis cases during the pandemic has posed a new challenge for clinicians. The mortality rate of CAM exceeded 50% despite aggressive medical and surgical interventions (2, 3).

Mucormycosis, formerly known as zygomycosis, is a highly aggressive, invasive fungal infection affecting a diverse patient group. It is caused by fungi collectively called Mucorales, commonly associated withCunninghamella, Rhizomucor, Apophysomyces,Rhizopus, Mucor, Lichtheimia, and Saksenaea (4). The most prevalent predisposing factors include granulocytopenia, immunosuppression, diabetes, and penetrating trauma (5). Mucormycosis, colloquially known as "black fungus," has been frequently detected among COVID-19 patients, especially in India (6). Mucormycosis cases have been sporadically reported in developing countries, primarily in patients with uncontrolled diabetes or trauma, and have shown high rates of morbidity and mortality (7). Additionally, the increase in the incidence of mucormycosis in European countries and the USA over the last two decades is attributed to the rise in solid organ transplantation, hematological malignancy, and diabetes cases (8).

2. Objectives

Our goal was to identify the clinical profiles of patients with CAM, compare them with a control group, and identify risk factors for the development of CAM.

3. Methods

Kayseri City Education and Research Hospital is a tertiary education center and regional hospital with 1,600 beds. From September 2020 to October 2022, 39 cases of CAM were recorded at Kayseri City Education and Research Hospital. Proven mucormycosis was defined as a patient with compatible clinical and radiological features and showing aseptate broad hyphae that were branching at right angles on direct microscopic examination of tissue/sterile material and showing invasive hyphae in tissues with or without positive fungal culture on histopathological examination. Cases with a positive reverse transcriptionpolymerase chain reaction for SARS-CoV-2 during the 60 days before mucormycosis diagnosis were considered CAM (case group) (9). COVID-19 was diagnosed by positive reverse transcription polymerase chain reaction (RT-PCR). The control group was selected blindly in a 1:2 ratio among patients who did not develop mucormycosis and were hospitalized, discharged, or died due to COVID-19, to be similar to the case group regarding age and hospitalization date. Demographic characteristics of the patients, underlying comorbidities, infection site, clinical findings of the infection, treatment given, and in-hospital mortality were recorded.

We utilized the IBM SPSS Statistics Windows edition (Release 27.0.1.0) for statistical analysis. In the statistical evaluation of the data obtained from the study, categorical data were summarized in frequency and percentage, and discrete variables were summarized in terms of mean ± standard deviation or median value (interquartile range), depending on the data distribution. After the normal distribution test of continuous variables was performed, the independent sample t-test was used for two-group comparisons for those with normal distribution, and the non-parametric Mann-Whitney U test was used for two-group comparisons for variables incompatible with normal distribution. Normality checks for continuous measurements were tested with the Shapiro-Wilk test. The level of statistical importance was accepted as 0.05. We used the multivariate binary logistic regression analysis to test potential risk factors for CAM. We developed a model that included gender, diabetes, cumulative dose of steroids (dexamethasone equivalent), duration of steroid treatment, and tocilizumab/anakinra treatment.

4. Results

In our study, 39 patients were diagnosed with CAM. The average age of the patients in our study was 66 ± 11.5 years. The average age of the CAM group was 66.9 ± 11.6 years, and the average age of the control group was 65.6 ± 11.5 years (P = 0.556). Of the patients, 54.7% (n = 64) were male, and the proportion of men was statistically significantly higher in the CAM group (74.4% vs. 44.9%, P = 0.003). The diabetes rate was 51.3% (n = 60) in all patients, and the diabetes rate was higher in the CAM group (69.2% vs. 42.3%, P = 0.006). Regarding in-hospital mortality, the mortality rate was higher in the CAM group (56.4% vs. 14.1%, P < 0.001). A group comparison of the patients in terms of comorbidities is shown in Table1.

When patients were examined regarding length of stay (LOS) in the hospital, the median was 13 days (9 -24.5). The median LOS in the hospital for the CAM group was 37 days, while it was 10 days for the control group (P < 0.001). The rate of hospitalization in intensive care was higher in the CAM group (76.9% vs. 16.7%, P < 0.001), whereas the rate of hospitalization in the ward was higher in the control group (23.1% vs. 83.3%, P < 0.001). The cumulative steroid dose was higher in the CAM group compared to the control group (191 ± 61.4 vs. 117 ±69.8, P < 0.001). The duration of steroid treatment was 16.5 ± 6.2 days in the CAM group, while it was 9.8 ± 4.7 days in the control group (P < 0.001) (Table 1).

In the between-group comparison, male gender was associated with a 3.6-fold (95% CI: 1.5 - 8.3) higher likelihood of CAM, and diabetes was associated with a 3.1-fold (95% CI: 1.4 - 6.9) higher likelihood of CAM. Similarly, the duration of steroid therapy was associated with a 1.2 - fold (95% CI: 1.1 - 1.3) higher odds of CAM. When the patients were examined in terms of laboratory values, the median creatine value of the patients in the CAM group was higher (1.15 vs. 0.92 mg/dL, P = 0.002). Similarly, the median values of procalcitonin (0.17 vs. 0.12 µg/L), fibrinogen (5665 vs. 5060 mg/L), and ferritin (720 vs. 502 µg/L) were found to be higher in the CAM group (P = 0.021, 0.05, and 0.008, respectively) (Table 2). A group comparison of the patients regarding laboratory values is shown in Table 2.

When the characteristics of the CAM group were examined, it was determined that paranasal involvement was the most common (56.4%), followed by rhino-orbital involvement (33.3%) (Figure 1 and Table 3). Microscopic and histopathological examination of biopsy materials from all patients revealed hyphae typical of Mucorales (Figure 2). Mucor was grown in the cultures of 34 (87.2%) of the patients. It was determined that 16 patients (41%) were treated with combined antifungal therapy (Liposomal Amphotericin B + Posaconazole), and 30 patients (76.9%) underwent more than one sinoscopic debridement. The most common finding in mucormycosis cases was nasal ulcer or necrosis (51.3%), followed by periorbital swelling (48.7%), proptosis (46.2%), and facial swelling (46.2%). The average time between the date of COVID-19 identification and the onset of Mucor symptoms was 21.7 ± 15.6 days.

In binary logistic regression analysis, male gender(OR, 3.9; 95% CI, 1.4 – 11.3), diabetes mellitus (OR, 4.4; 95% CI, 1.5 – 12.4), more than ten days of steroid use (OR, 5.5; 95% CI, 1.3 – 22.4), and tocilizumab/anakinra use (OR, 0.23; 95% CI, 0.06 – 0.8) were identified as risk factors for the development of CAM (p values 0.011, 0.005, 0.019, and 0.020, respectively) (Table 4).

5. Discussion

Our study is the only case-control study with the highest number of CAM patients conducted in Turkey. As a regional hospital, we are a tertiary care center visited by many patients from surrounding provinces. Our aim was to identify risk factors for the development of CAM. In our study, 39 cases were diagnosed with CAM. The average age was 66 ± 11.5 years. Male gender was associated with a 3.6-fold higher odds of CAM, and diabetes was associated with a 3.1-fold higher odds of CAM. Similarly, the duration of steroid therapy was associated with a 1.2-fold higher odds of CAM. It was observed that the median creatine, procalcitonin, and fibrinogen values of the patients in the CAM group were higher. In binary logistic regression analysis, male gender, diabetes mellitus, more than ten days of steroid use, and tocilizumab/anakinra use were identified as risk factors for the development of CAM.

Mucormycosis is a significant mortal disease that affects patients of all ages, with or without immunosuppression, depending on underlying risk factors. Mucormycosis is a rare infection in children; therefore, there are few case studies in the literature. An 8-year retrospective study conducted on 164 patients inIran determined that approximately one-quarter of the total population with mucormycosis comprised children (10). It has been stated that type 2 diabetes and widespread corticosteroid use may be responsible for the increase in mucormycosis with the COVID-19 pandemic in India. The rate of mucormycosis has increased significantly in people over 45 (11). In our study, the average age of the CAM group was 66.9 years, and there was no significant difference between them and the control group (65.6 years). A literature review published in 2022 examined clinical studies, metaanalyses, and systematic reviews to identify sex differences as a risk factor for invasive fungal diseases. The results showed a higher frequency of all fungal infections except invasive candidiasis in men (12). In our study, male gender was associated with a 3.6-fold (95% CI: 1.5 - 8.3) higher probability of CAM.

Research shows that individuals with diabetes are more susceptible to infections such as mucormycosis than healthy individuals. Diabetes is associated with high plasma glucose levels and acidic PH. In individuals with diabetes, the immune system may be weakened, increasing the risk of infection. In particular, rare diseases such as mucormycosis can lead to severe consequences in individuals with diabetes. Various factors, including a decrease in T lymphocyte count, neutrophilic dysfunction, leukocyte apoptosis, and impaired dendritic cell function, may play a role in the severe complications linked to mucormycosis in diabetic individuals (13). Our research findings reveal that diabetes significantly increases the risk of developing CAM, with an odds ratio of 4.4 (OR, 4.4; 95%CI, 1.5 – 12.4).

In our study, the in-hospital mortality rate was 56.4%. A study published in 2005 that reviewed 929 cases of mucormycosis found that the overall all-cause mortality rate was 54%. The mortality rates associated with mucormycosis in this investigation displayed variability contingent upon the patient's foundational health condition, fungal strain, and anatomical site of infection. Noteworthy distinctions in mortality rates were observed among subjects afflicted with mucormycosis, with figures at 46% for sinus involvement, 76% for pulmonary afflictions, and 96% for disseminated manifestations (4). In our study, paranasal involvement was the most common form of Mucor in more than half of the CAM patients, and rhino-orbital involvement was second.

In addition to case reports indicating that CAM increases with steroid treatment and diabetes, hyperglycemia has been stated to be associated with the development of CAM, independent of pre-existing diabetes and high steroid treatment (14, 15). In our study, diabetes was a risk factor on its own. However, more than ten days of steroid therapy rather than the cumulative dose of steroid therapy was a significant risk factor for CAM (OR, 5.5; 95% CI, 1.3 – 22.4). Hyperinflammation and cytokine storm are known to cause lung damage in COVID-19, and tocilizumab, an IL-6 receptor antagonist, has been shown to positively affect survival and respiratory function (even at low doses) (16). Similarly, anakinra is a recombinant IL-1 receptor antagonist used in COVID-19 and has been reported to reduce the progression to severe disease and the need for mechanical ventilation (17). In our study, tocilizumab/anakinra use was a negative risk factor for the development of CAM (OR, 0.23; 95% CI, 0.06 – 0.8).

The main limitation of our study is that it is retrospective and single-center. There is a need for multicenter studies in which more patients will be examined to support our findings.

5.1. Conclusions

In our study, more than half of the CAM patients died despite medical and surgical treatments. Male gender, diabetes mellitus, and steroid use for more than ten days were positive risk factors, and tocilizumab/anakinra use were negative risk factors for the development of CAM. We believe that clinicians should be more cautious about steroid therapy and its duration, as well as diabetes.

Sidebar

Received 2024 April 2; Revised 2024 April 24; Accepted 2024 April 29.

Footnote

Corresponding author: Department of Infectious Diseases and Clinically Microbiology, Kayseri City Education and Research Hospital, Kayseri, Turkey. Email: [email protected]

Authors' Contribution: Study concept and design, A.K.T., and A.T.Ö.; analysis and interpretation of data, A.K.T., A.K., and İ.ç.; drafting of the manuscript, A.K.T.; critical revision of the manuscript for important intellectual content, H.S., E.E.E., and İ.Ö.; statistical analysis: A.K.T..

Conflict of Interests Statement: The authors have no conflict of interest.

Data Availability: The dataset presented in the study is available on request from the corresponding author during submission or after publication. The data is not publicly available due to the patient's name and identification numbers.

Ethical Approval: This study was approved by the Kayseri City Education and Research Hospital Ethics Committee (decision no: 869, decision date: 11.07.2023). The authors confirm adherence to the ethical policies on the journal's author guidelines page and affirm that necessary approval from an ethics review committee has been acquired.

Funding/Support: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Informed consent: Written informed consent was obtained from the participants.

References

References

1. Elliott L. Chile detects first case of Covid 'black fungus'. London: The Sunday Times; 2021, [cited 2023]. Available from: https://www.thetimes.co.uk/article/chile-detects-first-case-of-covidblack-fungus-j87dkshb0.

2. Ozbek L, Topcu U, Manay M, Esen BH, Bektas SN, Aydin S, et al. COVID19-associated mucormycosis: a systematic review and meta-analysis of 958 cases. Clin Microbiol Infect. 2023;29(6):722-31. [PubMed ID: 36921716]. [PubMed Central ID: PMC10008766]. https://doi.org/10.1016/j.cmi.2023.03.008.

3. Balushi AA, Ajmi AA, Sinani QA, Menon V, Berieki ZA, Shezawi AA, et al. COVID-19-associated mucormycosis: an opportunistic fungal ınfection. A case series and review. Int J Infect Dis. 2022;121:203-10. [PubMed ID: 35533833]. [PubMed Central ID: PMC9075983]. https://doi.org/10.1016/j.ijid.2022.05.005.

4. Roden MM, Zaoutis TE, Buchanan WL, Knudsen TA, Sarkisova TA, Schaufele RL, et al. Epidemiology and outcome of zygomycosis: a review of 929 reported cases. Clin Infect Dis. 2005;41(5):634-53. [PubMed ID: 16080086]. https://doi.org/10.1086/432579.

5. Cornely OA, Arikan-Akdagli S, Dannaoui E, Groll AH, Lagrou K, Chakrabarti A, et al. ESCMID and ECMM joint clinical guidelines for the diagnosis and management of mucormycosis 2013. Clin Microbiol Infect. 2014;20 Suppl 3:5-26. [PubMed ID: 24479848]. https://doi.org/10.1111/1469-0691.12371.

6. Slavin M, Thursky K. Mucormycosis: the black fungus hitting Covid-19 patients. Regents Park, London: BBC Future; 2021, [cited 2023]. Available from: https://www.bbc.com/future/article/20210519mucormycosis-the-black-fungus-hitting-indias-covid-patients.

7. Toppo M, Gour D, Lodha RS, Kamble M, Keerthana S. A case-control study on mucormycosis in tertiary care hospital, Bhopal. Indian J Community Med. 2022;47(3):396-9. [PubMed ID: 36438517]. [PubMed Central ID: PMC9693956]. https://doi.org/10.4103/ijcm.ijcm_1320_21.

8. Patel AK, Bakshi H, Shah K, Patel S, Patel T, Patel K, et al. Risk factors for COVID-19 associated mucormycosis in India: A case control study. Med Mycol. 2022;60(7). [PubMed ID: 35709394]. [PubMed Central ID: PMC9214138]. https://doi.org/10.1093/mmy/myac044.

9. Dulski TM, DeLong M, Garner K, Patil N, Cima MJ, Rothfeldt L, et al. Notes from the field: COVID-19-associated mucormycosis - Arkansas, July-September 2021. Morb Mortal Wkly Rep. 2021;70(50):1750-1. [PubMed ID: 34914674]. [PubMed Central ID: PMC8675658]. https://doi.org/10.15585/mmwr.mm7050a3.

10. Motamedi M, Golmohammadi Z, Yazdanpanah S, Saneian SM, Shafiekhani M. Epidemiology, clinical features, therapeutic interventions and outcomes of mucormycosis in Shiraz: an 8-year retrospective case study with comparison between children and adults. Sci Rep. 2022;12(1):17174. [PubMed ID: 36229497]. [PubMed Central ID: PMC9561111]. https://doi.org/10.1038/s41598-022-21611-8.

11. Chavda VP, Apostolopoulos V. Mucormycosis - An opportunistic infection in the aged immunocompromised individual: A reason for concern in COVID-19. Maturitas. 2021;154:58-61. [PubMed ID: 34364730]. [PubMed Central ID: PMC8295237]. https://doi.org/10.1016/j.maturitas.2021.07.009.

12. Egger M, Hoenigl M, Thompson G3, Carvalho A, Jenks JD. Let's talk about sex characteristics-As a risk factor for invasive fungal diseases. Mycoses. 2022;65(6):599-612. [PubMed ID: 35484713]. https://doi.org/10.1111/myc.13449.

13. Khanna M, Challa S, Kabeil AS, Inyang B, Gondal FJ, Abah GA, et al. Risk of mucormycosis in diabetes mellitus: A systematic review. Cureus. 2021. https://doi.org/10.7759/cureus.18827.

14. Iqtadar S, Hashmat M, Chaudhry MNA, Mumtaz SU, Abaidullah S, Pascual-Figal DA, et al. Unnecessary use of corticosteroids for managing early mild symptoms of COVID-19 may lead to rhinoortibal-cerebral mucormycosis in patients with diabetes - a case series from Lahore, Pakistan. Ther Adv Infect Dis. 2022;9:20499361221097400. [PubMed ID: 35547833]. [PubMed Central ID: PMC9083038]. https://doi.org/10.1177/20499361221097417.

15. Ponnaiah M, Ganesan S, Bhatnagar T, Thulasingam M, Majella MG, Karuppiah M, et al. Hyperglycemia and steroid use increase the risk of rhino-orbito-cerebral mucormycosis regardless of COVID-19 hospitalization: Case-control study, India. PLoS One. 2022;17(8). e0272042. [PubMed ID: 35939442]. [PubMed Central ID: PMC9359565]. https://doi.org/10.1371/journal.pone.0272042.

16. Celik I, Eryilmaz-Eren E, Kilinc-Toker A, Eren D, Yildiz M, Kanat A, et al. Low-dose tocilizumab is associated with improved outcome and a low risk of secondary infection in severe COVID-19 pneumonia. Int J Clin Pract. 2021;75(12). e14997. [PubMed ID: 34714574]. [PubMed Central ID: PMC8646570]. https://doi.org/10.1111/ijcp.14997.

17. Khani E, Shahrabi M, Rezaei H, Pourkarim F, Afsharirad H, Solduzian M. Current evidence on the use of anakinra in COVID-19. Int Immunopharmacol. 2022;111:109075. [PubMed ID: 35905562]. [PubMed Central ID: PMC9296834]. https://doi.org/10.1016/j.intimp.2022.109075.