The legacy effect of a home walking exercise programme in kidney failure patients on dialysis

BACKGROUND: The EXerCise Introduction To Enhance performance (EXCITE) trial (J Am Soc Nephrol 28: 1259-1268, 2017) in dialysis patients showed that a 6-month home walking exercise programme improves physical function and two dimensions of the Kidney Disease Quality of Life Short Form (KDQOLSF-SF™) questionnaire. Whether improvements in physical function achieved by exercise interventions are maintained in the long term has never been tested in the dialysis population. METHODS: In this post-trial study embedded in the EXCITE trial, we tested the response to the 6 min walking test (6MWT) and the 5-time Sit-To-Stand (5STS) tests and the KDQOLSF-SF™ from the 6th month (end of the trial) to the 36th month. RESULTS: Among the 227 patients of the EXCITE trial cohort, 162 underwent at least three out of four testing visits (baseline, 6, 18 and/or 36 months) contemplated by the study protocol and 89 during all four testing visits. In the primary analysis by the linear mixed model, the gain in walking distance achieved in the 6th month in the exercise group [between-arms difference: +36 m, 95% confidence interval (CI): 22-51, P < .001] was maintained at the 18th month (between-arms difference: +37 m, 95% CI: 19-57, P < .001) and reduced to 23 m (95% CI: -4 to 49 meters, P = .10) at the 36th month. Overall, the post-trial difference in walking distance trajectories between the two study arms was highly significant (P = .004). Furthermore, the walking distance changes at the 6th (r = 0.34, P = .018) and 18th month (r = 0.30, P = .043) were directly related to the number of structured exercise sessions completed during the trial (i.e. the first 6 month). No such effect was registered in the response to the 5STS or in quality of life as measured by the KDQOLSF-SF™. CONCLUSIONS: In dialysis patients, the benefits of a 6-month structured walking programme outlast the duration of the intervention and postpone the loss of walking performance which naturally occurs in this population, but does not affect the quality of life (QoL) and the response to the STS test.