Impaired mobility at the time of dialysis initiation is an important risk factor for short-term mortality in elderly patients. Now, new data from a Japanese retrospective study suggest that a decline in mobility after the initiation of dialysis is also associated with reduced survival in this population. Arai and colleagues divided 202 patients aged >75 years into subgroups on the basis of their mobility at the time of initiation of dialysis and during 6 months of follow-up monitoring. They report that 24.8% of patients had impaired mobility at dialysis initiation and 68.9% of patients showed a decline in mobility whilst on dialysis. Moreover, patients who were independently mobile at dialysis initiation but whose mobility subsequently declined, and those who had impaired mobility at the onset of dialysis, had increased risks of short-term mortality compared with patients who were independently mobile at dialysis initiation and at 6 months.