Sex Differences in the EXerCise Introduction to Enhance Performance in Dialysis Trial

Key Points Inactivity in patients with ESKD worsens quality of life, function, and increases morbidity. Post hoc analysis of the EXerCise Introduction to Enhance Performance in Dialysis trial explores 6-month exercise effects in dialysis patients, stratified by sex. Sex-based findings may inform tailored interventions to enhance function and quality of life in patients with ESKD. Background Physical inactivity in patients with ESKD is linked to poor quality of life, lower physical function, and higher morbidity. Promoting physical activity and improving performance is vital for their care. This post hoc analysis of the EXerCise Introduction to Enhance Performance in Dialysis trial examined the effects of a 6-month exercise program for dialysis patients stratified by sex. Methods In the EXerCise Introduction to Enhance Performance in Dialysis trial participants were randomized into an exercise versus a control group. Eligible patients were recruited from 13 centers over November 2009–February 2011 and were followed for 36 months. This analysis focused on sex-stratified effects, including 227 dialysis patients (151 men, 76 women) who completed the 6-minute walking distance (6MWD) test and the five times sit-to-stand (5STS) test at baseline and after 6 months. The primary outcomes were changes in 6MWD and 5STS over a 6-month period. Data were analyzed using linear regression models to assess sex as an effect modifier. Results Both male (+37.1 versus +12.6 m, P = 0.005) and female (+42.7 versus −18.5 m, P < 0.001) patients in the exercise group showed significant improvements in 6MWD compared with controls. In unadjusted ( P = 0.02) and fully adjusted ( P = 0.006) interaction analyses, the response to this test in women improved more than in men. In sex-stratified analyses, the between-group difference in the response to the 5STS was numerically larger in women (−2.5 versus +0.4 seconds, P = 0.007) than in men (−2.4 versus −1.2 seconds, P = 0.06), but this difference did not reach statistical significance in interaction analysis (unadjusted, P = 0.15; fully adjusted, P = 0.11). Conclusions The exercise program improved physical performance in dialysis patients, with women showing more significant enhancements in 6MWD. These exploratory findings suggest that sex-specific physiologic differences may influence exercise outcomes in dialysis patients. Clinical Trial registry name and registration number: NCT01255969.