A systematic review and meta-analysis suggests obesity predicts onset of chronic kidney disease in the general population

Obesity and chronic kidney disease (CKD) are public health priorities that share core pathophysiological mechanisms. However, whether high body mass index (BMI) increases risk of CKD de novo remains ill-defined. To evaluate the role of BMI in predicting CKD onset in the general adult population, we performed a systematic review and meta analysis of PubMed and ISI Web of Science databases articles published between January 2000 and August 2016 without language restriction. We selected studies in adult individuals from a general population with normal renal function at baseline that reported the risk of low estimated glomerular filtration (eGFR) (under 60 mL/min/1.73m(2)) and/or albuminuria (1 + at dipstick or an albumin creatinine ratio of 3.4 mg/mmol or more) as hazard ratio, odds ratio or relative risk related to obesity, overweight, or BMI as continuous value. A total of 39 cohorts covering 630, 677 participants with a mean follow-up of 6.8 years were selected. Obesity increased the relative risk, 95% confidence interval and heterogeneity (I-2) of developing low eGFR (1.28, 1.07-1.54, [I-2: 95.0%]) and albuminuria (1.51, 1.36-1.67, [I-2: 62.7%]). Increase of BMI unit was also associated with higher risk of low eGFR (1.02, 1.01-1.03, [I-2: 24.3%]) and albuminuria (1.02, 1.00-1.04, [I-2: 0%]). Conversely, overweight did not predict onset of either low eGFR (1.06, 0.94-1.21, [I-2: 50.0%]) or albuminuria (1.24, 0.98-1.58, [I-2: 49.4%]). Thus, a high BMI predicts onset of albuminuria without kidney failure (CKD stages 1-2) as well as CKD stages 3 and higher, the effect being significant only in obese individuals. Hence, our findings may have implications to improve risk stratification and recommendations on body weight control in the general population.