Increased Mortality Rate after Hospitalization Among Chronic Hemodialysis Patients: A Prospective Cohort Study

Background/Aims: Hemodialysis patients are at high risk of hospitalization and their condition may worsen with repeated hospitalization. The aim of this study was to evaluate the impact of the cumulative number of hospitalizations on post-discharge mortality. Methods: This study was a prospective cohort study. We examined 3,359 adult patients onhemodialysis for at least 90 days who participated in the Japanese Dialysis Outcomes and Practice Patterns Study phases 3 and 4 (2005-2012). The patients hospitalized within 3months before enrollment were excluded. The main exposure was the time-varying cumulative number of hospitalizations during the follow-up period. Hazard ratios (HRs) for all-cause mortality rate after discharge were estimated by time-dependent Cox regressions after adjusting for potential confounders. Results: The median follow-up time was 2.7 years, and 873 (26%) patients experienced at least 1 hospitalization during follow-up. The hospitalization rate was 0.23 per person-year and the mortality rate was 0.036 per person-year. The HR and 95% CI for post-discharge mortality increased as the cumulative number of hospitalizations increased: once, 1.41 (0.99-2.00); and twice or more, 2.27 (1.59-3.23). The cause-specific hospitalization categories, infectious disease and cancer, affected post-discharge mortality HRs in a similar manner: 2.41(1.32-4.41) and 2.70 (1.23-5.93), respectively. Conclusion: A higher cumulative number of hospitalizations is associated with increased post-discharge mortality in chronic hemodialysis patients. The cause-specific hospitalizations category of infectious disease showed an impact on mortality similar to that of hospitalization for cancer. Therefore, physicians should pay more attention to reducing preventable hospitalizations.