Introduction

There has been a substantial increase in the number of cases of heart failure, worldwide.1,2 The concept of “heart failure pandemic” has been proposed to describe this spike in the cases of heart failure, and has been recognized as a global social/economic issue.2 Patients with heart failure frequently require hospital admission,3,4 and readmission.5 In a previous multicenter cohort study in Japan (JCARE-CARD), the heart failure rehospitalization rate within 6 months was reported to be 27%.4 The medical costs for heart failure management increase dramatically with inpatient care.5,6 Therefore, preventing hospital readmission of patients with heart failure is a priority from a public health perspective, with respect to healthcare costs, and the burden on patients and hospital staff. While heart failure cases require frequent readmission,3,4 there is evidence to suggest that intensive post-discharge care can reduce the risk of readmission.7,8,9,10 Timely emergency home visits might even possibly reduce the deterioration of symptoms, thereby preventing hospital admission.11

Since Japan’s population is rapidly aging,12 and healthcare costs are increasing,13 the government is promoting a shift of health care from the hospital-level to the community-level.14 In 2006, the Ministry of Health, Labor, and Welfare (MHLW) introduced “Home Care Support Clinics and Hospitals” (HCSCs) with home care support functions available 24 h/day.15 HCSCs are expected to make emergency house calls in the case of a patient’s condition suddenly deteriorating and to play a central role in end-of-life care at home in order to enable the patients to stay home until the end of life. To further enhance the role of home healthcare, the MHLW introduced “Enhanced HCSCs” in 2012, with the aim of providing more emergency house calls and end-of-life care.15 The distribution of HCSCs varies with population density, with more enhanced HCSCs located in urban regions and more conventional HCSCs located in rural areas.16

We hypothesize that conventional and enhanced HCSCs can reduce the risk of readmission in patients with heart failure.

Methods

Study Design and Data Source

We conducted a retrospective cohort study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) between April 2014 and March 2016. The NDB is a Japanese administrative claims database managed by the MHLW; it covers approximately 98% of the data on healthcare services provided by healthcare institutions,17 excluding medical practices that are not reimbursed by health insurance. The NDB contains information on claims, anonymous individual identification numbers, age (5-year age groups) and sex of patients, disease code, medical care procedures, and drug prescriptions. Procedures and medications are coded with the original Japanese codes. Diagnoses can be linked to the International Classification of Diseases, 10th Revision (ICD-10) codes.

Details of Home Care Support Clinics and Hospitals

Home healthcare in Japan entails physicians making regular home visits to diagnose and monitor medical conditions, as well as prescribing medications. To be enrolled in physician-led home healthcare, patients apply or are identified by the primary care physician as requiring home healthcare. A patient may also be referred by a hospital doctor for home healthcare after being discharged from the hospital. The patients must reside within roughly 16 km of clinics/hospitals that provide home healthcare. Physicians are required to make regular home visits once or twice a month, depending on the patient’s medical needs. Additionally, patients who receive physicians’ home visits often use nursing care visits and home help services offered by a variety of care facilities.18 To be qualified for reimbursement, the HCSCs (introduced in 2006) need to have home care support functions available 24 h a day until the patient dies,15 according to the patient’s request (this is a conventional requirement of all HCSCs). Enhanced HCSCs were introduced in 2012. They augment HCSCs by providing additional home healthcare services including emergency house calls and end-of-life care.15,19 Enhanced HCSCs are eligible for higher fees and are required to have three or more full-time doctors and to have provided ten or more emergency house calls and four or more cases of end-of-life care in the past year.19 The number of conventional and enhanced HCSCs facilities is increasing.19 Although many general clinics do not offer home healthcare, some of them provide.20,21 A large portion of the patients getting home healthcare at HCSCs (particularly enhanced HCSCs) were initially referred by other medical facilities, whereas at general clinics, many of the patients originally visited those clinics as outpatients.19

Study Population

We identified patients who were hospitalized for heart failure (ICD-10 code I50) and discharged between July 2014 and August 2015 and received regular home visits by the general clinics, conventional HCSCs or enhanced HCSCs, within 1 month following discharge. For patients with multiple eligible hospital admissions, we considered the first admission as the index admission. The exclusion criteria were (i) length of stay < 4 days or > 90 days, to exclude potentially planned examination and very complex or unstable cases; (ii) patients undergoing major cardiovascular procedures during hospitalization; (iii) patients aged < 65 years, because the vast majority (over 95%) of regular home visits are conducted for patients aged 65 and older22; (iv) patients with terminal malignancies at the time of discharge; (v) patients who were readmitted or died before the first home visit; and (vi) patients who used two or more types of home healthcare visits: general clinics, conventional HCSCs, or enhanced HCSCs within 1 month after discharge.

Exposure and Outcome

The exposure was the type of medical facility that provides home healthcare: general clinics, conventional HCSCs, and enhanced HCSCs.

The primary outcome was all-cause readmission within 6 months after the first home healthcare visit. The secondary outcome was emergency house calls. Death without any readmission (and all cause readmission for the secondary outcome) before the end of the follow-up period was considered a competing event as it precluded the occurrence of the event of interest. Death was confirmed by the outcomes of inpatient or outpatient services or by the surcharges of the death certificate or end-of-life care.23

Covariates

We also extracted age group; sex; etiology of heart failure (including ischemic, hypertensive, valvular, arrhythmia, and other cardiac diseases); comorbidities on discharge post index hospitalization (including cerebrovascular diseases, lower respiratory tract diseases, joint diseases, dementia, Parkinson’s disease, diabetes, visual of hearing impairment, fractures, cancer, anemia, and renal failure); medical procedures or medications administered during index hospitalization (including the use of respirator/non-invasive positive pressure ventilation (NPPV), oxygen therapy, admission to the intensive care unit (ICU), coordination with community care, use of intravenous diuretics, vasodilators, and vasoconstrictor agents); and medical procedures performed in home healthcare (including self-injection, central venous nutrition, home oxygen therapy, use of ventilator/tracheostomy performed, and pacemaker). Coordination with community care includes pre-discharge home visits or conferences that promote coordination between hospital staff and home healthcare staff to provide post discharge instructions to patients and their families. Medical interventions performed in home healthcare were identified by the month following discharge. By contrast, the etiology of heart failure and comorbidities was identified during the 3 months before the patient got discharged from the index hospitalization. The ICD-10 codes for the etiology of heart failure and comorbidities are provided in Appendix 1. “Suspected” diagnosis codes were excluded from the datasets.

Statistical Analysis

We calculated descriptive statistics for each variable, according to the type of post-discharge home healthcare. These characteristics were compared using χ2 tests. Then, we conducted a multivariate survival analysis to compare the risk of primary and secondary outcomes between general clinics, conventional HCSCs, and enhanced HCSCs. To account for the competing risk of death without readmission (and all-cause readmission for the secondary outcome), we specified a Fine and Gray regression model to model the cumulative incidence function and estimate subdistribution hazard ratios (sHRs), adjusting for all of the aforementioned covariates.24,25

We performed several sensitivity analyses to examine the robustness of our analysis. First, we started the follow-up of patients 1 month after discharge, instead of the first home visit in the main analysis. This “landmark analysis” may prove more effective in reducing the influence of immortal time bias,26,27 in exchange for the reduced sample size and generalizability by excluding patients with readmission within one month following discharge. Next, the secondary outcome was redefined as the average number of emergency house calls per month during the observation period, instead of the first emergency house call in the main analysis. We calculated the average number of emergency house calls per month by dividing the total number of emergency house calls by the number of months that each person received regular home visits, and used a multivariable negative binomial regression model for the association with this outcome. Third, a propensity score–matched analysis was performed to adjust for the difference in baseline characteristics between each post-discharge home healthcare type. We performed 1:4 match using the nearest neighbour with a calliper equal to 0.2 standard deviation of the propensity scores.28 All of the aforementioned covariates were used to estimate the propensity score. For balance assessment after matching, we calculated standardized mean difference and considered values < 0.1 acceptable.28 We compared primary and secondary outcomes between general clinics and conventional HCSCs, and between general clinics and enhanced HCSCs, separately.

All analyses were conducted using STATA version 15 (Stata Corp., Texas, USA) and R version 4.1.1 (R Foundation for Statistical Computing, Vienna, Austria). Statistical significance was set at P < 0.05.

Ethical Considerations

This study was approved by the ethics committee of the University of Tsukuba (approval number: 1476-2). Informed consent from individuals was waived since the NDB data were anonymized before they were made available to the researchers.

Results

Study Population and Baseline Characteristics

We included 12,393 patients with heart failure, including 1009 in the general clinic, 4681 in the conventional HCSCs, and 6703 patients in the enhanced HCSC groups (Fig. 1). Table 1 shows the characteristics of the participants according to the type of post-discharge home healthcare. Compared with people who used conventional HCSCs or enhanced HCSCs, those who used general clinics were more likely to be older and female; less likely to have dementia, fracture, and cancer; and less likely to be admitted to the ICU and to take coordination with community care and medical procedures at home.

Figure 1
figure 1

Flow chart of study participant selection. HCSCs, home care support clinics/hospitals.

Full size image
Table 1 Characteristics of Patients in the Three Types of Post-Discharge Home Healthcare
Full size table

Results for Primary Outcomes

At the end of the 6-month follow-up, 43.0% of patients (434/1009) in the general clinic group, 38.1% (1784/4681) in the conventional HCSC group, and 38.1% (2556/6703) in the enhanced HCSC group were readmitted at least once. The overall 6-month mortality was 24.0% (242/1009) in the general clinic group, 27.0% (1267/4681) in the conventional HCSC group, and 29.6% (1982/6703) in the enhanced HCSC group. Competing events were 10.1% (102/1009) in the general clinic group, 14.9% (698/4681) in the conventional HCSC group, and 17.0% (1140/6703) in the enhanced HCSC group, as the patients died without any readmission. Figure 2 shows the cumulative incidence of the outcome considering the competing risk; the post-discharge home healthcare administered by conventional and enhanced HCSCs were associated with a lower risk of readmission than that administered by general clinics, while there was no difference between the conventional and enhanced HCSC groups. Compared to general clinics, the adjusted sHR for readmission were 0.87 (0.78–0.96) and 0.86 (0.78–0.96) for conventional HCSCs and enhanced HCSCs, respectively. The analysis with patient follow-up beginning 1 month after discharge (Appendix 2) and the propensity score–matched analysis also showed similar results (Appendices 3–6).

Figure 2
figure 2

Cumulative incidence of the 6-month readmission considering competing risk by the type of post-discharge home healthcare. HCSCs, home care support clinics/hospitals. Note: Curves of conventional HCSCs and enhanced HCSCs mostly overlap.

Full size image

Results for Secondary Outcomes

During the 6-month follow-up period, 29.8% patients (301/1009) in the general clinic group, 46.7% patients (2186/4681) in the conventional HCSC group, and 50.5% patients (3388/6703) in the enhanced HCSC group had at least one emergency house call (Fig. 3). There was a difference in the incidence of emergency house calls between conventional and enhanced HCSCs. Compared to general clinics, the adjusted sHR were 1.77 (1.57–2.00) and 1.93 (1.71–2.17) for conventional HCSCs and enhanced HCSCs, respectively. These findings were robust to our sensitivity analysis, conducting multivariable negative binomial regression for the average number of emergency house calls per month (Appendix 7) and propensity score–matched analysis (Appendices 3–6).

Figure 3
figure 3

Cumulative incidence of the emergency house calls considering competing risk by the type of post-discharge home healthcare. HCSCs, home care support clinics/hospitals.

Full size image

Discussion

Conventional and enhanced HCSCs were associated with decreased readmission rates, and more emergency house calls, than general clinics. These results suggest that conventional and enhanced HCSCs may be more effective in reducing readmission, compared to general clinics.

The readmission rates in our study were higher than a previous Japanese study in which 27% of patients required readmission within 6 months, which is similar to the readmission rates reported in Europe and the USA.4 Given that the participants in our study were patients receiving home healthcare and that these patients had low activities of daily living (ADL) and numerous comorbidities, it was not surprising that readmission rates were generally high. Our findings show that physician-led home healthcare resulted in higher readmission compared to general readmission rates; this is consistent with the findings of a previous study.29

We also found that conventional and enhanced HCSCs were associated with lower readmission rates, which is in line with a previous study that evaluated 30-day readmission rates for all diseases.30 While the mechanism by which HCSCs resulted in fewer readmissions was unknown in the previous study, our results revealed that patients in the HCSC groups had more emergency house calls than patients in the general clinic group, which may possibly explain why HCSCs have fewer readmissions. Previous studies in foreign countries have also reported that a higher provision of home visits was associated with fewer hospital admissions.11,31 Readmission is required when there is a lack of timely access to medical resources, and symptoms are not detected and treated at an early stage; thus, emergency house calls could be effective in lowering readmission rates. Another possible explanation may be the differences in the usual care and multidisciplinary team management of HCSCs, such as collaboration with nurses and the use of home rehabilitation, which were not available in this database.10,32

On the other hand, our results showed no difference in readmission rates between conventional HCSCs and enhanced HCSCs. This may be because the distribution and roles of conventional and enhanced HCSCs differ by region.16 Since enhanced HCSCs are more common in urban areas and less common in rural areas,16 conventional HCSCs in rural areas may perform the role of enhanced HCSCs. It is also possible that there are no differences between conventional and enhanced HCSCs in the rates of emergency department visits and readmission.

The type of post-discharge home healthcare for patients in this study was determined by the clinic they originally attended or by referral from the hospital where they were admitted for heart failure to a medical facility providing home healthcare, depending on the healthcare resources in the area. Because of the spread of HCSCs since their introduction in 2006, the number of patients who use general clinics among those receiving home healthcare has declined. In addition, since more patients who utilize HCSCs are referred from other medical facilities,16 HCSC use is considered more prevalent in this post-discharge situation. However, given that a certain percentage of patients still receive home healthcare from general clinics, it is important to compare the outcomes between general clinics and HCSCs. Although this study is not a randomized controlled trial, the results were obtained using real-world data with sufficient adjustment for patient characteristics. Furthermore, sensitivity analysis using propensity score matching showed similar results, supporting the validity of our findings.

In Japan, the average admission period for patients with heart failure is ≥ 2 weeks, and the healthcare costs per person is estimated to exceed one million yen ($10 thousand).33,34 With the advent of the “heart failure pandemic,” our results suggest that those still in general clinics should consider switching to HCSCs to reduce the patient burden and cost of heart failure in Japan. For other countries, services such as HCSCs (i.e., services with home care support functions available 24 h a day) may reduce readmissions, and randomized controlled trials would be desirable in countries where such services are not yet standard. Although the number of HCSCs is increasing,19 a previous report shows that more than 70% of clinics that provide home healthcare with one or two physicians feel burdened by the 24-h system, while clinics with three or more full-time physicians feel less burdened.35 Since most conventional HCSCs are single physician practices and have difficulty providing three or more full-time doctors,36 new measures may need to be considered to reduce the burden on primary care physicians and maintain the community healthcare, such as delegating home visits to another healthcare professional,37,38 or establishing organizational models for after-hours medical care, as in other countries.39

This study had several limitations. First, the NDB in Japan does not contain laboratory and imaging data; therefore, we were unable to assess the severity of heart failure. Instead, we used ventilator/NPPV and oxygen use and ICU admission as factors indicating severity, which may not be perfect proxies. In addition, the observed association could have been influenced by residual confounding factors, such as patients’ ADLs, the homecare services used by the patients, and socioeconomic factors. Second, although the decision to hospitalize or continue treatment at home when the condition deteriorated could be influenced by the patient’s wishes, family situation, and advanced care planning, we were unable to examine these factors as potential mechanisms of the reduced readmission in the conventional and enhanced HCSC groups because we did not have these data. Finally, we did not have data on the myriad reason patients and their families perceived the need to request emergency house calls. This may have been influenced by appropriate symptom management, palliative care, and family caregiver education and support.

Conclusion

In this national-level study in Japan, we found that post-discharge care administered by the conventional and enhanced HCSCs was associated with lower readmission rates and more emergency house calls than general clinics among older patients with heart failure, receiving home healthcare. In the face of increasing demand for home healthcare, our results support the introduction and promotion of HCSCs to reduce the burden on patients and society. Further studies are necessary to confirm the medical functions performed by HCSCs.