Remnant cholesterol increases the risk of incident kidney stones: a nested case-control study in Chinese adults

Kidney stones pose a significant healthcare burden worldwide. Dyslipidemia is a risk factor for kidney stones, but the relationship between remnant cholesterol (RC) and kidney stone risk is unknown. We aimed to investigate the association between RC and the risk of incident kidney stones. We conducted a nested case-control study based on data from Shanghai Kidney Stone Cohort conducted in Shanghai from December 2018 to February 2023. Propensity score matching was used to select 2550 incident kidney stone cases and 7650 controls from a total of 60,158 adults. Baseline fasting plasma samples were collected to measure RC, which was calculated as total cholesterol minus high-density lipoproteins cholesterol and low-density lipoproteins cholesterol. Multivariable conditional logistic regression and a restricted cubic spline were used to estimate the association between tertiles of RC and kidney stone risk. Subgroup and sensitivity analyses were also performed. The baseline RC of incident kidney stone cases and controls were 0.58 (0.57) and 0.54 (0.55), respectively. Incident kidney stones had much higher baseline RC levels than controls (P < 0.001). Higher baseline RC levels were significantly associated with increased kidney stone risk after adjustment for potential confounders (highest vs. lowest tertile: OR 1.16, 95% CI 1.04-1.30; per 1 mmol/L increase: OR 1.16, 95% CI 1.07-1.26). Restricted cubic spline showed a significant positive and linear dose-response relationship between RC and the risk of developing kidney stones (P-overall = 0.005, P-nonlinear = 0.482). Sensitivity analyses yielded consistent results. Elevated RC levels are associated with a greater risk of incident kidney stones in Chinese adults.