Mixed Results on Functional Impact of Frequent Hemodialysis

Increasing hemodialysis frequency from three times to six times weekly improves subjective but not objective measures of physical functioning, reports a trial in the Clinical Journal of the American Society of Nephrology.

The researchers analyzed data on physical performance, health, and functioning in patients enrolled in two Frequent Hemodialysis Network (FHN) trials: 245 in the daily FHN trial and 87 in the nocturnal FHN trial. In both studies, patients were randomly assigned to frequent or conventional hemodialysis: six versus three times per week.

Consistent with other studies of hemodialysis patients, 12-month scores on the short physical performance battery (SPPB), the RAND 36-item health survey physical health composite (PHC), and the physical functioning subscale were below population norms. Patients assigned to frequent hemodialysis in the daily trial had a significant 3.4-point improvement in the PHC score, as well as a relatively large (but nonsignificant) improvement in the physical functioning subscale.

In contrast, there was no significant change in the SPPB score. None of the three measures showed a significant difference between frequent and conventional hemodialysis in the nocturnal trial.

Previous FHN trial reports have suggested beneficial effects of frequent hemodialysis, including a reduced risk of death or change in left ventricular mass. The new analysis evaluated the effects of hemodialysis frequency on important disability outcomes.

The results show significant improvement in patient-reported measures of physical health and functioning with in-center hemodialysis performed six versus three times per week. However, objective assessments of physical performance are not significantly improved. Neither type of outcome is altered for patients assigned to more frequent nocturnal hemodialysis [Hall YN, et al: Effects of six versus three times per week hemodialysis on physical performance, health, and functioning: Frequent Hemodialysis Network (FHN) randomized trials. Clin J Am Soc Nephrol 2012; 7: 782–794].