Association of Obesity With Kidney and Cardiac Outcomes Among Patients With Glomerular Disease: Findings From the Cure Glomerulonephropathy Network

Abstract

Rationale & ObjectiveThe influence of obesity on cardiorenal outcomes in individuals with glomerular disease is incompletely known. This study examined the association between obesity and kidney and cardiovascular outcomes in children and adults with glomerular kidney disease. Study DesignProspective, multicenter, observational study. Setting & ParticipantsParticipants in the Cure Glomerulonephropathy Network (CureGN) who were ≥5 years of age at enrollment. ExposuresAdult body mass index (BMI) groups: 20-24 (healthy) vs 25-34 (overweight/class 1 obesity) vs ≥35 (class 2/3 obesity); and Pediatric BMI Percentiles: 5th – 84th (healthy) vs 85th – 94th (overweight) vs ≥95th (obese). OutcomesA composite kidney outcome (40% eGFR decline or kidney failure) and a composite cardiovascular outcome (myocardial infarction, stroke, heart failure, or death) Analytical ApproachTime to composite primary outcomes by BMI strata were estimated using Kaplan-Meier analysis. The adjusted associations between BMI and outcomes were estimated using Cox proportional hazards analysis. ResultsThe study included 2301 participants (1548 adults and 753 children). The incidence of the primary kidney endpoint was 90.8 per 1000 person-years in adults with class 2/3 obesity, compared with 58.0 in normal weight comparators. In the univariable analysis class 2/3 obesity was associated with the primary kidney outcome only in adults (HR 1.6, 95% CI 1.1-2.2, p = 0.006) compared to the healthy weight groups. In the multivariable adjusted analysis, class 2/3 obesity did not remain significant among adults when controlling for baseline eGFR and proteinuria. Adults with class 2/3 obesity had an incidence of 19.7 cardiovascular events per 1000 person-years, and greater cardiovascular risk (HR 3.9, 95%CI 1.4-10.7, p = 0.009) in the fully adjusted model. LimitationsBMI is an imperfect indicator of adiposity. Residual confounding may exist from socioeconomic factors. ConclusionsAmong adult patients in CureGN, class 2/3 obesity is associated with cardiovascular but not kidney outcomes when adjusted for potential confounding factors.