Accessing the relationship between six surrogate insulin resistance indexes and the incidence of rapid kidney function decline and the progression to chronic kidney disease among middle-aged and older adults in China: Results from the China health and retirement longitudinal study

Aims: Insulin resistance is closely related to kidney function decline, but which insulin resistance index could better predict rapid kidney function decline (RKFD) remains unclear. We aimed to evaluate the prospective association between six insulin resistance indexes: Chinese Visceral Adiposity Index (CVAI), Lipid Accumulation Product (LAP), Atherogenic Index of Plasma (AIP), triglyceride-glucose (TyG) index, triglyceride-glucose x Body Mass Index (TyGBMI) and triglyceride-glucose x waist circumference (TyGWC) with RKFD and further the progression to chronic kidney disease (CKD). Methods and measurements: Data were obtained from the China Health and Retirement Longitudinal Study. Participants with normal kidney function (eGFRcr-cys >= 60 ml/min per 1.73 m(2)) and >= 45 years old were included at the baseline (year 2011). The eGFR was estimated by a combination of serum creatinine and cystatin C. The primary outcome was RKFD, defined as an annualized decline in eGFRcr-cys of 5 ml/min per 1.73 m(2) or more. Secondary outcome was progression to CKD under the condition of RKFD, defined as an annualized decline in eGFRcr-cys of 5 ml/min per 1.73 m(2) or more combined with eGFRcr-cys <60 ml/min per 1.73 m(2) at the exit visit. Logistic analysis was applied for analysis of the association between six insulin resistance indexes and RKFD or progression to CKD. We use receiver operating characteristic curves to study the predictive performance of six insulin resistance indexes. Subgroup analysis were conducted by diabetes or hypertension status of the participants. Results: A total of 3899 participants with normal kidney function were included in this study. After a 3.99 years follow-up, 191 of them ended up with RKFD. Among them, 66 participants progressed to CKD. Logistic analysis showed that per SD increase of all the six insulin resistance indexes were significantly associated with the incidence of RKFD (all P < 0.01), among which, TyGWC had the best predictive value for RKFD. There were significant association between per SD increase of CVAI, LAP, TyGBMI and TyGWC with progression to CKD (all P < 0.01), and CVAI had better predictive role than other indexes. In subgroup analysis, we found that the association between insulin resistance indexes and progression to CKD was more significant in subjects with hypertension or without diabetes. However, no significant differences were observed in the RKFD group. Conclusions: In this study we proved six insulin resistance indexes were predictively associated with RKFD in Chinese with normal renal function over age 45. TyGWC is the best insulin resistance index for predicting RKFD. CVAI is the best index for predicting further progression to CKD.