Metabolic health, obesity, and chronic kidney disease : findings from the national health and nutrition examination surveys.

Rising rates of metabolic syndrome, obesity, and death from chronic kidney disease (CKD) have prompted further investigation into the association between metabolic syndrome and CKD. The purpose of this study was to report the frequency of metabolic phenotypes, constellations, and clusters as well as their relationship to renal function in a representative sample of individuals in the United States. We utilized a subsample from the 2013-2018 National Health and Nutrition Examination Surveys (NHANES) and complex survey sample weighting techniques to represent non-institutionalized US civilians. Four metabolic phenotypes were identified including metabolically healthy normal weight (MHN), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUN), and metabolically unhealthy obese (MUO). Renal function as measured by estimated glomerular filtration rate (eGFR) was compared among the phenotypes. Sixteen possible constellations of 3 or more risk factors were classified and four metabolic clusters, which represented MetS with hyperglycemia (Cluster I), MetS with hypertension (Cluster II), MetS with hyperglycemia and hypertension (Cluster III) or MetS with normoglycemia and normotension (Cluster IV), were assessed for renal function and CKD status. The metabolically healthy normal (MUN) phenotype was most frequent in the subsample taken (38.40%). Renal function was lowest in this phenotype in the regression analysis (B= -9.60, p<0.001) and highest in the MHO (B= 2.50, p>0.05) and this persisted with more liberal definitions of metabolic syndrome. Systolic blood pressure had the strongest correlation with overall eGFR (r= -0.25, p<0.001) and individuals with low HDL had higher renal function compared to the overall sample. The constellation with the lowest renal function consisted of hypertension, high triglycerides, and large waist circumference (82.86 ml/min/1.73m2). Cluster III had the highest odds of CKD (OR=2.57, 95%CL=1.79, 3.68) and Clusters II and III had the lowest renal function (87.82 and 87.28 ml/min/1.73m2, respectively). In conclusion, the metabolically unhealthy phenotypes had the lowest renal function regardless of weight status. Metabolic constellations and clusters with hypertension as a risk factor had low renal function. HDL had a small negative correlation with renal function, indicating that more research should be done in this area.