Clinical Characteristics and Five-Year Outcomes of Patients Aged 75 Years or Older Receiving Maintenance Hemodialysis at a Japanese Regional Core Hospital

Introduction The number of older patients receiving maintenance hemodialysis is increasing in Japan. Patients aged 75 years or older often have multimorbidity, frailty, nutritional vulnerability, and a higher risk of adverse clinical outcomes than younger patients. However, real-world longitudinal data from regional hospitals regarding mortality and clinically important complications in this population remain limited. This study aimed to compare five-year mortality, baseline clinical characteristics, laboratory findings, GI bleeding, and fractures between maintenance hemodialysis patients aged 75 years or older and those younger than 75 years. Methods This retrospective, single-center, longitudinal observational study included all eligible patients receiving maintenance hemodialysis at Takagi Hospital, a regional core hospital in Fukuoka, Japan, on December 1, 2017. Patients were categorized by baseline age into an older group aged 75 years or older and a younger group younger than 75 years. Baseline demographic, clinical, and laboratory data were extracted from electronic medical records. Follow-up continued until death or December 2022. The primary outcome was five-year all-cause mortality. Secondary outcomes included cause-specific mortality, endoscopy-confirmed GI bleeding, imaging-confirmed fractures, and baseline laboratory parameters. Between-group comparisons were performed using Student’s t-test for continuous variables and the chi-square test for categorical variables. Results A total of 151 patients were analyzed, including 57 patients aged 75 years or older and 94 patients younger than 75 years. Five-year all-cause mortality was significantly higher in the older group than in the younger group (34/57 (59.6%) vs. 21/94 (22.3%), P < 0.001). Deaths due to renal failure and infection were also more frequent in the older group (21.1% vs. 6.4%, P = 0.007; and 19.3% vs. 5.3%, P = 0.007, respectively), whereas cerebrovascular/cardiovascular mortality did not differ significantly between groups (7.0% vs. 8.5%, P = 0.742). Upper-body fractures occurred more frequently in the older group than in the younger group (21.1% vs. 6.4%, P = 0.007), while lower-body fractures and gastrointestinal bleeding showed no statistically significant differences. The older group had significantly lower serum albumin and phosphorus levels than the younger group. Conclusion Among maintenance hemodialysis patients treated at a single regional Japanese hospital, a baseline age of 75 years or older was associated with higher five-year all-cause mortality, more frequent upper-body fractures, and lower serum albumin and phosphorus levels. These findings suggest that older hemodialysis patients may require individualized, multidisciplinary care focused on nutritional status, infection prevention, fracture and fall risk, and supportive care. Because this was a retrospective single-center study, further multicenter prospective studies are needed to validate these findings and clarify targeted interventions for this vulnerable population.