Metabolically Healthy Obesity and Risk of Kidney Function Decline

OBJECTIVE: To examine the association between body mass index (BMI) categories, stratified by metabolic health status, and risk of kidney function decline METHODS: We classified 42,128 adult patients with stable BMI over a 3-year baseline window by BMI and metabolic health status (assessed by Adult Treatment Panel-III criteria). Kidney function decline (KFD) was defined as eGFR decline ≥ 30%, eGFR<15 ml/min/1.73m(2), or receipt of dialysis/transplant. RESULTS: Over a median of 5.1 years (IQR 2.1–8.9), 6,533 (15.5%) individuals developed KFD. Compared to the normal weight, metabolically healthy category, metabolically healthy obesity (MHO) was associated with higher risk of KFD [adjusted hazard ratio (aHR) 1.52, 95% CI: 1.22– 1.89]. Adjusted HRs for KFD were 1.17 (95% CI: 0.89 –1.53), 2.21 (95% CI: 1.59 – 3.08), and 2.20 (95% CI: 1.55–3.11) for MHO with BMI 30–34.9, BMI 35–39.9, and BMI ≥ 40 kg/m(2). These associations were consistent among men and women, patients with eGFR ≥ or < 90 ml/min/1.73m(2), and age ≥ or < 55 y. Risk of KFD was highest among metabolically unhealthy individuals with BMI ≥ 40 (aHR 4.02, 95% CI: 3.40–4.75 vs. metabolically healthy, normal weight individuals). CONCLUSIONS: Obesity, whether in the presence or absence of metabolic health, is a risk factor for KFD.