Abstract
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 14,917 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 1,847 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, 2,150 participants (25.9 per 1,000 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 1,000 person-year) than without (24.2 per 1,000 person-year, p < 0.001). Moreover, each MetS 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 1,000 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.
Plain Language Summary
Kidney is an organ of the silence because a symptom of kidney disease appears only in its end stage. However, kidney disease even in its early stage is a risk of cardiovascular events, a leading cause of death worldwide. It is extremely difficult to restore impaired kidney function. Early detection or primary prevention of kidney disease is quite important; thus, identifying individuals with increased risk of developing kidney disease is one of the most attractive approaches to reduce a burden of cardiovascular disease. Metabolic syndrome (MetS) is a condition that several metabolic disorders are clustered, and kidney disease often coexists with a component of metabolic disorders, such as increased blood pressure, impaired glucose tolerance, and dyslipidemia. The present study investigated whether MetS is a risk of kidney disease. A total of 14,917 subjects with normal kidney function were enrolled and followed up for 5 years with the endpoint of kidney disease. During the follow-up, 2,150 participants developed kidney disease and the occurrence of the disease was more frequent in individuals who had MetS at baseline than in those who did not. Moreover, each metabolic disorder was associated with future occurrence of kidney disease and the risk of kidney disease increased with increasing the number of metabolic disorders. Testing for MetS and its components can help identify individuals at increased risk of developing kidney disease.