Metabolic disorders predict future impairment of kidney function in the Japanese general population

Abstract

Abstract Background/Introduction Metabolic syndrome (MetS) which is defined as accumulation of visceral fat followed by a cluster of metabolic disorders is one of the most important risk factors of cardiovascular morbidity and mortality. Although the close relationship between kidney dysfunction and cardiovascular events have also been reported, the association of kidney dysfunction with MetS remains unidentified. Purpose The present study investigated whether MetS or its components predict future deterioration of kidney function in the general population. Methods Consecutive 14917 subjects with normal estimated glomerular filtration rate (eGFR; ≥60mL/min/1.73m²) who visited our hospital for a physical check-up from 2008 to 2018 (male=8876, 51.3±12.4 year-old) were enrolled and followed up until 2019 for 1847 days (median) with the endpoint being the development of impaired kidney function (eGFR<60mL/min/1.73m²). Metabolic syndrome was defined based on the Japanese diagnostic criteria (2005; waist circumference ≥85 cm for males and ≥90 cm for females and ≥2 of the following three criteria: (1) triglyceride≥150 mg/dL and/or high-density lipoprotein cholesterol < 40 mg/dL; (2) systolic blood pressure≥130 mmHg and/or diastolic blood pressure ≥85 mmHg; and (3) fasting plasma glucose ≥110 mg/dL). Participants who had medication for each metabolic disorder were considered to meet each criterion. Results During the follow-up, 2150 subjects (25.9 per 1000 person-year) developed impaired kidney function. The incidence was more frequent in subjects with (39.3 per 1000 person-year) than without MetS (24.2 per 1000 person-year, p<0.001). Moreover, each component of MetS showed a significant impact on the incident impaired kidney function (obesity 23.0 vs. 31.2, lipid 23.3 vs. 34.2, blood pressure 19.9 vs. 35.9, glucose 24.8 vs. 35.2 per 1000 person-year) and the incidence was increased with increasing the number of metabolic disorders in individuals at baseline (0, 1, 2 and ≥3 factor(s); 17.3, 26.9, 32.9 and 39.7 per 1000 person-year, respectively). Non-adjusted hazard ratio (HR) (95% confidence interval [CI]) of MetS for the new onset of impaired kidney function was 1.619 (1.447-1.810). In multivariate Cox hazard analysis adjusted for sex, age, pulse rate, serum creatinine, uric acid, hemoglobin, current smoking and frequent alcohol consumption, MetS was an independent predictor of the development of impaired kidney function (HR=1.312, 95%CI [1.167-1.475]). Similar results were obtained in sub-analysis using subjects without any medications (n=11963) (data not shown). Conclusions Metabolic syndrome and its components are important predictors for the development of impaired kidney function in the general population. Prediction of the deterioration of kidney function may lead to effective prevention of chronic kidney disease and relating cardiovascular disease.