The quantifying relationship between the remission duration and the cardiovascular and kidney outcomes in the patients with primary nephrotic syndrome

BACKGROUND: Patients with persistent nephrotic-range proteinuria have a high risk of kidney dysfunction and cardiovascular events. Recently, the maintenance of proteinuria remission has been demonstrated to reduce the risk of kidney endpoint. However, the effect of remission duration on cardiovascular outcomes remains unclear. METHODS: This study enrolled 982 patients with primary nephrotic syndrome who had achieved clinical remission. Remission duration was defined as the maintenance time (months) of the first remission. Arteriosclerotic cardiovascular disease (ASCVD) and kidney dysfunction (ESKD or eGFR reduction >50%) were the endpoints. Survival curves, Cox regression models, restricted cubic spline analysis were used and the cutoff time points were determined. RESULTS: During the 38.3 months of follow-up, 161 (16.4%) patients developed ASCVD (51.3 per 1000 patient-years) and 52 (5.3%) patients developed kidney dysfunction (15.3 per 1000 patient-years). Multivariate analysis showed that remission duration was an independently protective factor to ASCVD, in which each one-year extension associated with a 15% reduction of the risk (HR, 0.854; 95% CI, 0.776 ∼ 0.940, p = .001). The initial time point was seven months for remission to present the protective effect to ASCVD and the maximum time point was 36 months. Remission duration was also an independently protective factor to kidney dysfunction. This effect was shown from the beginning of remission and reached the maximum at 26 months. CONCLUSIONS: The maintenance of proteinuria remission was crucial for the improvement of cardiovascular and kidney outcomes in nephrotic syndrome patients.