Evaluating the association between walking speed and reduced cardio-cerebrovascular events in hemodialysis patients: A 7-year cohort study

Abstract

Background: Deterioration in walking ability characterized by slow walking speed is associated with an increased risk of mortality in patients on hemodialysis (HD), but few studies have examined the potential for walking speed to reduce the incidence of clinical events. In this study, we assessed a range of maximum walking speeds (MWS) with regard to their capacity to reduce cardio-cerebrovascular events in HD patients. Methods: In total, 188 Japanese outpatients (90 men, 98 women; mean age, 65 years) undergoing maintenance HD three times a week were monitored for 7 years. We measured clinical characteristics and MWS at baseline and followed these patients to track any cardio-cerebrovascular events. Patients were divided into quartiles (Q1 = lowest, Q4 = highest) based on MWS for each sex. Cox proportional hazards regression and Kaplan-Meier estimates were used to assess the contribution of MWS to cardio-cerebrovascular events. Results: During the follow-up period, cardio-cerebrovascular events occurred in 42 patients. After adjusting for potential confounders, the hazard ratio for events per 10 m/min increase in MWS was 0.77 (95 % confidence interval: 0.65-0.92; P = 0.004). Seven-year cumulative incidence rates were 36, 32, 13, and 9 % for Q1 through Q4, respectively, and a significant difference across MWS quartiles was observed (P < 0.001). While the incidence rates did not significantly differ between Q1 and Q2 or between Q3 and Q4, Kaplan-Meier curves clearly differed between Q2 and Q3. Conclusions: Our findings suggest that more than the MWS level of Q3 (≥89 m/min in men and ≥85 m/min in women) may serve as important MWS values for disease management in ambulatory HD patients.