Abstract
BACKGROUND: The triglyceride-glucose index (TyG index), calculated as the logarithmic product of fasting triglyceride and glucose concentrations, is recognized as a simple marker of insulin resistance. However, the association between the TyG index and future decline of renal function remains unclear in the general population. OBJECTIVE: To investigate whether the TyG index was associated with future decline of renal function in the general population who had not progressed to chronic kidney disease stage G2. DESIGN: Retrospective longitudinal observational cohort study. PARTICIPANTS: Individuals who received a population-based health checkup at JA Ehime Kouseiren Checkup Center from 2010 to 2019 (n = 134,007). Individuals without data of baseline fasting triglyceride or glucose levels, or baseline and follow-up data of estimated glomerular filtration rate (eGFR), or those with baseline eGFR < 60 mL/min/1.73 m(2) were excluded. MAIN MEASURES: Future renal function decline, defined as a ≥ 25% decrease in eGFR from baseline. KEY RESULTS: Of 10,758 participants, 8,076 were classified into the low TyG index group (TyG index < 8.76, 1st to 3rd quartiles) and 2,682 into the high TyG index group (TyG index ≥ 8.76, 4th quartile). The mean follow-up period was 37.8 ± 23.6 months. The incidence rates of renal function decline were 0.31 and 0.69 per 100 person-years in the low and high TyG index groups, respectively. In multivariate Cox proportional hazard models, high TyG index was significantly associated with future renal function decline (hazard ratio 2.25, 95% CI 1.40-3.60). This association was consistent across subgroups stratified by age, sex, body mass index, baseline eGFR, and diagnosed hypertension, diabetes, or dyslipidemia. CONCLUSION: In the general population, high TyG index was associated with future renal function decline. The TyG index may be useful in identifying individuals at high risk for future renal function decline in the setting of health checkups.