Association between metabolic disorders and impaired kidney function thereafter in the Japanese general population.

Introduction: Metabolic syndrome (MetS) and chronic kidney disease are both important risk factors for cardiovascular disease and are closely related to each other. We retrospectively investigated whether MetS or its components increase the risk of development of impaired kidney function in the Japanese general population.

Methods: This is a retrospective cohort study　which enrolled 14917 participants who visited our hospital for physical checkups from 2008 to 2018 and had normal estimated glomerular filtration rate (eGFR≥60 mL/min/1.73 m2) during the baseline examination. Participants were followed up for the median of 1847 days until 2019 with the development of impaired kidney function (eGFR<60 mL/min/1.73 m2) as the endpoint. The definition of MetS was based on Japanese diagnostic criteria (2005).

Results: Throughout the study, 2150 participants (25.9 per 1000 person-year) developed impaired kidney function after their baseline checkup. The incidence of impaired kidney function was more frequent in participants with MetS (39.3 per 1000 person-year) than without (24.2 per 1000 person-year, p<0.001). Moreover, each metabolic syndrome component was positively associated with the incidence of impaired kidney function, where the incidence of impaired kidney function increased with the number of MetS components at baseline (0, 1, 2 and ≥3 component(s); 17.3, 26.9, 32.9 and 39.7 per 1000 person-year, respectively). Multivariate Cox hazard analysis revealed that MetS was an independent risk factor for impaired kidney function after adjusting for known risk factors (hazard ratio, 1.29; 95% confidence interval, 1.15-1.45).

Conclusions: Testing for MetS and its components can help evaluate the risk of developing impaired kidney function in the general population.