Obesity, Metabolic Abnormality, and Progression of CKD

Abstract

Rationale & objective: Recent studies have yielded conflicting findings on the association between obesity and progression of chronic kidney disease (CKD). Few studies have evaluated whether metabolic abnormalities may accelerate the rate of progression of CKD.

Study design: Prospective observational cohort study.

Setting & participants: 1,940 participants from the Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD) PREDICTORS: Obesity and metabolic abnormality. Obesity was defined as body mass index ≥ 25kg/m². Metabolic abnormality was defined as the presence of 3 or more of the following 5 components: hypertension, fasting glucose level > 125mg/dL or the presence of type 2 diabetes, triglyceride level > 150mg/dL or use of lipid-lowering drugs, high-density lipoprotein cholesterol level ≤ 40mg/dL in men and ≤ 50mg/dL in women, and high-sensitivity C-reactive protein level > 1mg/L.

Outcome: A composite of a 50% decline in estimated glomerular filtration rate from the baseline value or end-stage kidney disease.

Analytic approach: Multivariable cause-specific hazards models implemented to assess the association between obesity, metabolic abnormality, and CKD progression.

Results: During a mean follow-up of 3.1 years, the primary outcome occurred in 395 (20.4%) patients. In multivariable analyses, after adjustment for confounding factors, obesity and metabolic abnormality were significantly associated with 1.41-fold (95% CI, 1.08-1.83; P=0.01) and 1.38-fold (95% CI, 1.03-1.85; P=0.03) increased risk for adverse renal outcomes, respectively. Patients were categorized into 4 groups depending on the presence of obesity and metabolic abnormality. Compared with those with neither obesity nor metabolic abnormality, those with obesity and metabolic abnormality had a greater risk for CKD progression (HR, 1.53; P=0.03). Those with obesity without metabolic abnormality also had a higher rate of CKD progression (HR, 1.97; P=0.01).

Limitations: Observational study, limited power to detect cardiovascular disease outcomes, unmeasured confounders.

Conclusions: Both metabolic abnormality and obesity are associated with a significantly increased risk for CKD progression. Notably, obese patients without metabolic abnormality also have an elevated risk for CKD progression.

Keywords: CKD progression; Chronic kidney disease (CKD); body mass index (BMI); end-stage renal disease (ESRD); estimated glomerular filtration rate (eGFR); kidney function; metabolic abnormality; metabolic syndrome; obesity; renal outcome.