The risk of chronic kidney disease (CKD) is increased in patients who are obese; however, it is unclear whether the increased risk is due to obesity itself or to the associated metabolic derangements. S. Ciardullo and colleagues conducted a cross-sectional study to examine the relative impact of obesity and metabolic syndrome (MS) on kidney disease. Results were reported online in the American Journal of Nephrology [doi.org/10.1159/000518111].
The study utilized data obtained in the 2005-2016 cycles of the National Health and Nutrition Examination Survey. Eligible patients were adults with available data on body mass index, estimated glomerular filtration rate (eGFR), urine albumin to creatinine ratio (UACR), and each of the MS components. The main outcomes of interest were eGFR <60 mL/min/1.73 m2, UACR ≥30 mg/g, or a combination of the two.
The study included 12,335 participants. Obese participants without MS were younger and more commonly female. Following adjustment for potential confounders, compared with non-obese participants without MS, there was an increased prevalence of albuminuria and reduced eGFR among those without obesity with MS and among those with obesity and MS; there was no increase in prevalence among participants with obesity but without MS.
In separate evaluations of each MS component, there were associations between elevated blood pressure and low high-density lipoprotein cholesterol and UACR and reduced eGFR. Elevated blood glucose and triglycerides were only associated with UACR. There was no association between waist circumference and any of the renal outcomes.
In summary, the researchers said, “This large cross-sectional study suggests that MS and not obesity is associated with kidney damage and that the obesity without MS phenotype does not seem to carry an increased risk of kidney disease.