Cause-specific excess mortality among dialysis patients: comparison with the general population in Japan

Despite significant therapeutic advances, mortality of dialysis patients remains unacceptably high. The aim of this study is to compare mortality and its causes in dialysis patients with those in the general Japanese population. We used data for 2008 and 2009 from the Japanese Society for Dialysis Therapy registry and a national Vital Statistics survey. Cardiovascular mortality was defined as death attributed to heart failure, cerebrovascular disorders, myocardial infarction, hyperkalemia/sudden death, and pulmonary thromboembolism. Non-cardiovascular mortality was defined as death attributed to infection, malignancies, cachexia/uremia, chronic hepatitis/cirrhosis, ileus, bleeding, suicide/refusal of treatment, and miscellaneous. We calculated standardized mortality ratios and age-adjusted mortality differences between dialysis patients and the general population for all-cause, cardiovascular versus non-cardiovascular, and cause-specific mortality. During the 2-year study period, there were 2,284,272 and 51,432 deaths out of 126 million people and 273,237 dialysis patients, respectively. The standardized mortality ratio for all-cause mortality was 4.6 (95% confidence interval, 4.6-4.7) for the dialysis patients compared to the general population. Age-adjusted mortality differences for cardiovascular and non-cardiovascular disease were 33.1 and 30.0 per 1000 person-years, respectively. The standardized mortality rate ratios were significant for all cause-specific mortality rates except accidental death. Our study revealed that excess mortality in dialysis patients compared to the general population in Japan is large, and differs according to age and cause of death. Cause-specific mortality studies should be planned to improve life expectancies of dialysis patients.