Metabolic Syndrome, and Not Obesity, Is Associated with Chronic Kidney Disease

Introduction: Obese (OB) patients are at increased risk of chronic kidney disease, but it is still unclear whether this can be attributed to obesity per se or to the associated metabolic derangements. The aim of this study was to evaluate the relative impact of obesity and metabolic syndrome (MS) on kidney disease. Methods: This is a cross-sectional study based on data obtained in the 2005–2016 cycles of the National Health and Nutrition Examination Survey. We included all adult participants with available data on body mass index, estimated glomerular filtration rate (eGFR), urine albumin to creatinine ratio (UACR), and each of the MS components. Primary outcomes were eGFR <60 mL/min, UACR ≥30 mg/g, or a combination of the two. Results: The studied population comprised 12,335 participants. OB participants without MS (OB+ MS−) were younger and more commonly female. After adjustment for potential confounders, compared with OB− MS− participants, an increased prevalence of albuminuria and reduced eGFR were present in both OB− MS+ groups and the OB+ MS+ groups, but not in the OB+ MS− groups. When each of the MS components was evaluated separately, elevated blood pressure and low high-density lipoprotein cholesterol were associated with both UACR and reduced eGFR, while elevated blood glucose and triglycerides were only associated with UACR. Waist circumference was not associated with any of the renal outcomes. Discussion/Conclusion: This large cross-sectional study suggests that MS and not obesity is associated with kidney damage and that the OB+ MS− phenotype does not seem to carry an increased risk of kidney disease.