The Association of Excess Body Weight with Risk of ESKD Is Mediated Through Insulin Resistance, Hypertension, and Hyperuricemia

Background Insulin resistance, hypertension, hyperuricemia, and hypercholesterolemia are hypothesized to be important intermediates in the relationship between excess body weight and CKD risk. However, the magnitude of the total effect of excess body weight on ESKD mediated through these four pathways remains to be quantified. Methods We applied a model for analysis of correlated mediators to population-based data from 100,269 Austrian individuals (mean age 46.4 years). Association of body mass index (BMI) was coalesced with ESKD risk into direct association. Indirect associations were mediated through the triglyceride-glucose (TyG) index (as an indicator of insulin resistance), mean arterial pressure (MAP), uric acid (UA), and total choles-terol (TC). Results Mean follow-up was 23.1 years with 463 (0.5%) incident ESKD cases. An unhealthy metabolic pro -file (prevalence 32.4%) was associated with a markedly increased ESKD risk (multivariably adjusted hazard ratio (aHR), 3.57; 95% CI, 2.89 to 4.40), independent of BMI. A 5-kg/m(2) higher BMI was associated with a 57% increased ESKD risk (aHR(total association), 1.57; 1.38 to 1.77). Of this association, 99% (76% to 140%) arose from all mediators jointly; 33% (22% to 49%) through TyG index; 34% (24% to 50%) through MAP; 30% (21% to 45%) through UA; and 2% (21% to 4%) through TC. The remaining direct association was nonsignificant (aHR(direct association), 1.01; 0.88 to 1.14). Conclusions TyG index, MAP, and UA, but not TC, mediate the association of BMI with ESKD in middle-aged adults. Our findings highlight that in addition to weight reduction, the control of metabolic risk factors might be essential in mitigating the adverse effects of BMI on kidney function.

Automated summary

This study found that insulin resistance, blood pressure, and uric acid mediate the association between excess body weight and ESKD in middle-aged adults, while total cholesterol does not play a role. In addition to weight reduction, controlling metabolic risk factors may be essential in mitigating the adverse effects of BMI on kidney function.