Cardiac disease is the second leading cause of death in Japan, and the number of patients with this condition is increasing. Arrhythmia is a major cause of sudden death among patients with cardiac disease. Treatment for arrhythmia includes drug therapy with antiarrhythmic drugs and non-pharmacotherapies such as catheter ablation and device implantation, and the goal of these treatments is to improve the prognosis and the quality of life of patients. Among these treatments, device implantation, which has been covered by insurance in Japan since 1974, increased to having been used in a total of 79 972 cases in 2021, possibly due to the evolution of smaller, lighter implantable devices such as cardioverter defibrillators and cardiac resynchronization therapy devices. Various device implantation procedures are recommended by the JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.1
Conversely, cardiac rehabilitation (CR) is also performed for patients with cardiovascular diseases such as acute myocardial infarction, after cardiac surgery, and after heart failure, and its effectiveness has been recognized. In addition, comprehensive CR involvement not only improves exercise tolerance but also the quality of life and mental health of patients. In Japan, medical treatment is provided according to the medical fee system set by the Ministry of Health, Labour, and Welfare, and CR may be provided to some patients within the scope of the requirements set forth by this system.
The guidelines are yet to be established regarding CR for patients with arrhythmias, who are often restricted in their activities to prevent the occurrence of arrhythmias. In contrast, CR after device implantation is recommended by the Guideline on Rehabilitation in Patients with Cardiovascular Disease,2 and the effects of CR on patients undergoing device implantation for arrhythmias have been recently reported.3–7 Although there have been reports of trends in the dissemination of CR using diagnosis procedure combination (DPC) data in Japan,8 only patients hospitalized for myocardial infarction, angina pectoris, heart failure, peripheral vascular disease, and cardiovascular surgery are eligible for the program, while the implementation status of CR after device implantation has not yet been clarified. In particular, an analysis of the implementation of CR after device implantation using a large database may yield important and useful information reflecting the current status in medical practice. The purpose of this study was to verify the implementation status of CR among patients with heart disease who have undergone device implantation using real-world data.
METHODS SubjectsThis was an observational study using a nationwide administrative database associated with the DPC system in Japan. The subjects were patients with heart disease who had undergone device implantation, such as pacemaker implantation, implantable cardiac resynchronization therapy, implantable cardioverter defibrillator therapy, and implantable cardiac resynchronization therapy with a defibrillator. Of the 124 882 patients, 70 667 were included in the study, with the exclusion of patients under 15 years of age, those having undergone device implantation during unscheduled hospitalization, and those having undergone pacemaker generator replacement surgery (Figure 1).
This study was approved by the institutional review board of the University of Occupational and Environmental Health, Japan (Approval Code: R2-007), which waived the requirement for informed consent.
Data sourceThe DPC is a case-mix patient classification system launched by the Ministry of Health, Labour, and Welfare of Japan in 2002. It contains information about hospitalized patients, such as date of birth, admission, discharge, sex, primary injury (ICD-10 code), complications, comorbidities (using the Charlson comorbidity index), surgical procedures, other key indicators, and patient status at discharge. The database stores the data of 7 million patients annually from more than 1000 participating hospitals.9,10 Furthermore, the database includes the data of more than 50% of all acute-care inpatients and 90% of all tertiary-care emergency hospitals in Japan.10 During this study, we used the case data of patients discharged between April 2014 and March 2018.
Statistical analysisThe CR [CR (+)] group was defined as patients for whom some rehabilitation fee was calculated during hospitalization, while the no CR [CR (−)] group was defined as patients for whom no rehabilitation fee was calculated. The unpaired t-test and the chi-squared test were used to compare the characteristics of the CR (+) and the CR (−) groups. All statistical analyses were performed using STATA version 16 (Stata). A p- value of <.05 was considered statistically significant.
RESULTSThe study included 70 667 patients with cardiac disease who underwent device implantation (Figure 1). Table 1 presents the baseline characteristics of the patients. After device implantation, 16 445 patients (23%) underwent CR. The mean age of patients who underwent CR was 77 years, and the mean age of patients who did not undergo CR was 75 years. The mean age of patients in the CR group was significantly older.
TABLE 1 Patient characteristics
| All | CR(+) | CR(−) | p-value | ||||
| n | (%) | n | (%) | n | (%) | ||
| Number of patients | 70 667 | 16 445 | 54 222 | ||||
| Age (years), mean (SD) | 75.2 | (11.6) | 77.1 | (11.7) | 74.6 | (11.5) | <.001 |
| Sex | |||||||
| Male | 38 302 | (54) | 8235 | (50) | 30 067 | (55) | |
| Female | 32 365 | (46) | 8210 | (50) | 24 155 | (45) | |
| Device implantation | <.001 | ||||||
| Pacemaker | 60 239 | (85) | 13 030 | (79) | 47 209 | (87) | |
| Implantable cardioverter defibrillator | 3916 | (6) | 958 | (6) | 2958 | (5) | |
| Cardiac resynchronization therapy | 1614 | (2) | 581 | (4) | 1033 | (2) | |
| Cardiac resynchronization therapy with defibrillator | 4917 | (7) | 1887 | (11) | 3030 | (5) | |
| Comorbidity of heart disease | <.001 | ||||||
| Ischemic cardiomyopathy | 15 623 | (22) | 4271 | (26) | 11 352 | (21) | |
| Valvular disease | 5329 | (8) | 2754 | (17) | 2575 | (5) | |
| Heart failure | 28 588 | (41) | 9262 | (56) | 19 326 | (36) | |
| Cardiomyopathy | 4662 | (7) | 1471 | (9) | 3191 | (6) | |
| Atherosclerotic risk factors | <.001 | ||||||
| Hypertension | 34 093 | (48) | 7776 | (47) | 26 317 | (49) | |
| Diabetes mellitus | 634 | (1) | 191 | (1) | 443 | (1) | |
| Dyslipidemia | 10 831 | (15) | 2302 | (14) | 8529 | (16) | |
| Smoking history | 20 043 | (28) | 4333 | (26) | 15 710 | (29) | |
| Medication | <.001 | ||||||
| Beta blockers use | 8459 | (12) | 3006 | (18) | 5453 | (10) | |
| Amiodarone use | 4426 | (6) | 1938 | (12) | 2488 | (5) | |
| Comorbidity | <.001 | ||||||
| Charlson comorbidity index: 0 | 24 985 | (35) | 4110 | (25) | 20 875 | (38) | |
| Charlson comorbidity index: 1 | 25 770 | (37) | 6381 | (39) | 19 389 | (36) | |
| Charlson comorbidity index: ≧2 | 19 912 | (28) | 5954 | (36) | 13 958 | (26) | |
| Activities of daily living at admission | |||||||
| Barthel index (points), mean (SD) | 89.0 | (25) | 84.7 | (31) | 93.3 | (20) | <.001 |
| Length of stay | <.001 | ||||||
| Total length of hospital stay: 1–7 | 5377 | (8) | 184 | (1) | 5193 | (10) | |
| Total length of hospital stay: ≧8 | 65 290 | (92) | 16 261 | (99) | 49 029 | (90) | |
| Duration of hospital stay (days), mean (SD) | 23.7 | (54) | 33.6 | (95) | 13.8 | (14) | <.001 |
| Discharge destination | <.001 | ||||||
| Home | 65 110 | (92) | 13 350 | (81) | 51 760 | (95) | |
| Other hospital | 3486 | (5) | 2118 | (13) | 1368 | (3) | |
| Nursing home | 1561 | (2) | 633 | (4) | 928 | (2) | |
| Death | 477 | (1) | 328 | (2) | 149 | (0) | |
| Other | 32 | (0) | 16 | (0) | 16 | (0) | |
| Number of cases at the individual centers | |||||||
| Hospital volume: 1–65 | 18 231 | (26) | 4213 | (26) | 14 018 | (26) | .769 |
| Hospital volume: 66–125 | 16 666 | (24) | 3623 | (22) | 13 043 | (24) | .783 |
| Hospital volume: 126–205 | 18 490 | (26) | 4080 | (25) | 14 410 | (26) | .779 |
| Hospital volume: 206 | 17 280 | (24) | 4529 | (27) | 12 751 | (24) | .738 |
The implanted devices in the CR (+) group included pacemakers in 13 030 patients (79%), implantable cardioverter defibrillator in 958 patients (6%), cardiac resynchronization therapy pacemaker in 581 patients (4%), and cardiac resynchronization therapy defibrillator in 1887 patients (11%), respectively. In the CR (+) group, a smaller proportion of patients received a pacemaker and a larger proportion of patients received cardiac resynchronization therapy compared to the CR (−) group.
Patients in the CR (+) group were more likely to have various comorbid heart diseases or other diseases than patients in the CR (−) group. In addition, patients in the CR (−) group were more prone to atherosclerotic risk factors than patients in the CR (+) group.
The Barthel Index score, which is a measure of activities daily living (ADLs), was more than 85 points for 80% of patients at hospital admission. The mean Barthel Index score of the CR (+) group was 85 points, while that of the CR (−) group was 93 points. The mean Barthel Index score was significantly lower in the CR (+) group.
The total length of hospital stay was more than 8 days for 92% of cases. The total length of hospital stay was more than 8 days for 99% of CR (+) group; however, it was more than 8 days for 90% of the CR (−) group. The total length of the hospital stay was significantly longer for the CR (+) group. The outcome at discharge of patients were home in 92%, transfer to other hospitals in 5%, nursing home admission in 2%, and death in 1%. The outcome at discharge was 81% home and 13% transfer to other hospitals for the CR (+) group, and 95% home discharge and 3% transfer to other hospitals for the CR (−) group. Of the CR (+) group, a smaller proportion were discharged to the house and a larger proportion had transferred to other hospital compared to the outcomes in the CR (−) group.
Implementation rates of CR according to the hospital volume were comparable when divided into groups of <65 cases per year, 65–125 cases per year, 126–205 cases per year, and 206 or more cases per year.
Table 2 shows the percentage of the status of disease-specific rehabilitation fees in patients who underwent rehabilitation. A total of 69% of patients were undergoing CR fees, and 31% of the patients were undergoing non-CR fees.
TABLE 2 Status of disease-specific rehabilitation fee
| Number of cases | (%) | |
| Cardiac rehabilitation fees | 11 367 | 69.1 |
| Non-cardiac rehabilitation fees | 5078 | 30.9 |
Although device implantation for patients with heart disease has an important role in the treatment of arrhythmia, the implementation status of CR after device implantation in Japan is not clear yet. During this study, patients undergoing pacemaker replacement had a shorter duration of hospital stay, and patients admitted for device implantation during emergency admissions were excluded from the study because this may have prolonged the duration of the hospital stay and was likely to affect the outcome. This analysis aimed to help clarify the problems that need to be solved, and the results offer important implications for future decisions regarding treatment and medical policies for CR after device implantation among patients with heart disease.
The results of this study indicated that the implementation rate of CR after device implantation in Japan was 23% (n = 16 445), and the implementation rate of CR after device implantation in patients with comorbid heart failure was only 32% (n = 9262). It was reported that the implementation rates of CR after myocardial infarction, heart failure, and cardiac surgery in Japan were 66%, 47%, and 77%, respectively.11 The implementation rate of CR after device implantation was low compared to these rates. The rate of CR after device implantation in Japan did not differ according to hospital volume. CR after device implantation is recommended by the 2021 Revision of the Guidelines for Cardiovascular Disease Rehabilitation,2 and various meta-analyses have suggested the safety and efficacy of exercise.12–17 However, the provision of CR after device implantation in Japan may not be widespread, at least during the perioperative phase, regardless of the hospital volume.
Patients who underwent CR after device implantation were older and had lower Barthel Index scores at hospital admission than those who did not. Moreover, the CR (+) group had longer hospital stays and were transferred to other hospitals at a higher rate than the CR (−) group. These results suggest that for the subjects in the CR (+) group whose abilities to perform ADLs had been declining or were likely to decline before hospital admission, CR was proactively conducted to maintain and improve the physical functions of more severely challenged patients. CR after device implantation was regarded as an assistive intervention to be implemented with the aim of hospital discharge. However, it is necessary to recognize that CR after device implantation is, in fact, a treatment with established evidence of improving the long-term prognosis. Many patients have restricted activity and reduced exercise tolerance before device implantation and a gradual decline in physical activity after device implantation.18 CR after device implantation has been reported to improve not only physical function but also exercise tolerance, quality of life, mental health, and the re-hospitalization rate of patients with full independence performing ADLs.19–32 Furthermore, the implementation of CR is also important for evaluating chronotropic incompetence during exercise. During this study, the rate of those hospitalized for more than 8 days was more than 90% even among the CR (−) group after device implantation. As length of hospital stay is sufficiently long, CR should be recommended for most patients after device implantation, regardless of whether they can independently perform ADLs. We believe that CR during hospitalization is feasible and will contribute to reducing anxiety and increasing activity to improve the life expectancy after discharge, thus maximizing the benefits of device implantation surgery.
Additionally, regarding the medical fee calculation for rehabilitation after device implantation, 69% (n = 11 367) of patients were charged a CR fee and 31% (n = 5078) of patients were charged for other disease-specific rehabilitation fees. If not considered CR, then there is no comprehensive multidisciplinary intervention or safe practice under ECG monitoring supervision, and the patient benefits described by previous studies may not be expected. Rehabilitation is differentiated according to disease by the Japanese medical fee system, and each disease has its own criteria. This situation can be attributed to the fact that the current medical fee calculation conditions for left ventricular ejection fraction less than 40% and brain natriuretic peptide more than 80 pg/mL are criteria assumed mainly for patients with myocardial infarction and heart failure. The subjects of this study were patients with stable cardiac disease who were admitted for the purpose of device implantation; therefore, these criteria for calculation of CR do not apply here. The current criteria, which exclude stable cardiac disease, may have resulted in the lower rate of CR after device implantation. It will be necessary to collect data on CR after device implantation to provide more evidence.
This study had some limitations. First, it was a retrospective, database-based cohort study; thus, limited data were available. Therefore, the specific treatment and other details provided during CR were unknown. Second, this study did not distinguish between CR before and CR after device implantation. Patients who underwent CR before device implantation had lower ventricular function and heart failure before hospital admission, which may have affected the length of the hospital stay and outcomes after implantation. Third, the DPC data used during this study were large Japanese administrative data, but they represented a subset of all Japanese hospitals; thus, it is necessary to make careful generalizations. Finally, because this study only examined the implementation rate of CR after device implantation, we were unable to determine its effectiveness. In accordance with the purpose of this study, only univariate analysis was performed with no multivariate analysis; hence, the effects of confounding factors may not have been excluded. In the future, it will be necessary to verify the effectiveness of CR after device implantation in Japan by performing longitudinal and interventional studies based on long-term data.
CONCLUSIONSCR was performed for only one-quarter of all patients after device implantation and just one-third of the patients for device implantation with heart failure. Most patients were elderly and had impaired ability to perform ADLs. These results suggest that the subjects in this study underwent general rehabilitation to maintain and improve their physical function. Additionally, the calculation criterion for CR in Japan may have caused the lower rate of CR after device implantation. It is necessary to promote the importance of CR after device implantation and improve its implementation rate. The DPC data are subject to various limitations, and further research is necessary.
ACKNOWLEDGMENTSThis study was funded by a grant from the Ministry of Health, Labour and Welfare (MHLW) for scientific research.
FUNDING INFORMATIONNot applicable.
CONFLICT OF INTERESTThe authors have no conflicts of interest to disclose.
ETHICS APPROVAL STATEMENTThis study was approved by the institutional review board of the University of Occupational and Environmental Health, Japan (Approval Code: R2-007), and the research protocol followed the guidelines of the Declaration of Helsinki.
CLINICAL TRIAL REGISTRATIONNot Applicable.
PATIENT CONSENT STATEMENTThis study was deemed that written informed consent from the participants was unnecessary by the institutional review board.
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Details
; Matsugaki, Ryutaro 2 ; Imamura, Hanaka 2 ; Itoh, Hideaki 3 ; Oginosawa, Yasushi 4
; Araki, Masaru 4 ; Fushimi, Kiyohide 5 ; Matsuda, Shinya 2 ; Saeki, Satoru 3 1 Rehabilitation Center of University Hospital, University of Occupational and Environmental Health, Kitakyushu, Japan
2 Department of Preventive Medicine and Community Health, University of Occupational and Environmental Health, Kitakyushu, Japan
3 Department of Rehabilitation Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
4 Department of Health Policy and Informatics, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
5 Second Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan