Association between Obesity and Chronic Kidney Disease, Defined by Both Glomerular Filtration Rate and Albuminuria, in Korean Adults

Background: Chronic kidney disease (CKD) has often been defined based on glomerular filtration rate (GFR) alone. The Kidney Disease: Improving Global Outcomes guideline highlights albuminuria in the CKD definition. Thus, we investigated the association between obesity and CKD, as defined by both GFR and albuminuria, in Korean adults. Methods: We used Korea National Health and Nutrition Examination Survey 2011-2014 data (N = 19,331, ≥19 years old) representing the national Korean population. CKD was classified by (1) estimated GFR (eGFR) < 60 mL/min/1.73 m² (CKD_GFR); (2) albumin-to-creatinine ratio (ACR) ≥30 mg/gram (CKD_ACR); and (3) eGFR < 60 mL/min/1.73 m² or ACR ≥30 mg/gram (CKD_Risk). Associations between obesity and each CKD category were evaluated using multivariate logistic regression analysis. Results: The prevalence rates of CKD_GFR, CKD_ACR, and CKD_Risk were 2.2%, 6.7%, and 8.1%, respectively. Compared with the normal body mass index (BMI; 18.5-22.9 kg/m²) group, men with BMI ≥ 25 kg/m² had 1.88 times greater risk of CKD_GFR in the adjusted model [95% confidence interval (CI), 1.26-2.80; P = 0.002]; BMI was not significantly associated with CKD_GFR in women. In contrast, both men and women with BMI ≥ 25 kg/m² had 1.58 and 1.40 times higher risk of CKD_ACR (95% CI, 1.21-2.07 and 1.08-1.81, respectively, both P < 0.01). Obese men and women had 1.65 and 1.38 times higher risk of CKD_Risk (95% CI, 1.29-2.12 and 1.09-1.75, respectively, both P < 0.01). Conclusions: Obesity was significantly associated with an increased ACR-based CKD risk. Longitudinal studies are needed to investigate the role of overweight and obesity in the development and progression of CKD.