Early exercise therapy for acute nephrotic syndrome: a randomised clinical trial

In adults with acute nephrotic syndrome (NS), physical function often declines; however, limited evidence on the efficacy and safety of exercise therapy leads to its avoidance due to fears of exacerbated proteinuria and renal deterioration. This study aimed to assess whether early exercise therapy enhances physical function without elevating risks of non-remission or worsening kidney function.

This single-centre randomised controlled trial enrolled hospitalised adults receiving glucocorticoid therapy for NS. Participants were randomised (1:1) to exercise therapy or standard care. The primary outcome was peak oxygen uptake (peak VO2) at baseline and 6 weeks. The secondary outcome was non-remission at 6 weeks (proteinuria ≥0.3 g/day). Analyses used multiple imputation for missing data, analysis of covariance adjusted for baseline, and modified Poisson regression.

Twenty-seven participants were recruited (early intervention, n = 13; standard care, n = 14). Peak VO2 increased significantly in the early exercise group (Δ = 3.45 mL/kg/min; 95% confidence interval [CI], 1.22-5.67) but not in the standard care group (Δ = 1.00 mL/kg/min; 95% CI, -1.14 to 3.14). Adjusted between-group difference at 6 weeks was 2.46 mL/kg/min (95% CI, -0.12 to 5.03). Risk ratio for non-remission was 0.673 (95% CI, 0.266-1.703), with no significant intergroup difference.

Early exercise therapy in acute NS improved exercise tolerance clinically, although the primary outcome between-group difference was not statistically significant. No evidence indicated increased non-remission risk.

This trial was registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) (registration number: UMIN000038250; registration date: October 9, 2019).