Metabolic syndrome and its components are associated with increased chronic kidney disease risk: Evidence from a meta-analysis on 11109003 participants from 66 studies

Background & aims: Observational studies examining the relationship between metabolic syndrome and the risk of chronic kidney disease (CKD) have reported inconclusive results. This meta-analysis was performed to resolve these controversies. Methods: The MEDLINE, EMBASE, and PubMed databases were systematically searched from their inception until March 2016 to identify all relevant studies. Risk estimates and their corresponding 95% confidence intervals (CIs) for the associations of MetS and its components with CKD risk were extracted and pooled using a random-effects model. Results: A total of 66 studies, including 18 prospective cohorts and 48 cross-sectional studies, with 699065 CKD patients and 11109003 participants were included in the meta-analysis. When all definitions were pooled, the presence of MetS was associated with a significant 50% increase of CKD risk (OR=1.50, 95% CI=1.43-1.56), with evidence of moderate heterogeneity (I-2=72.3%, P<.001). The risk of CKD associated with MetS was higher in studies using the American Heart Association/National Heart, Lung, and Blood Institute criteria (OR=1.68, 95% CI=1.25-2.10) compared with those using the Adult Treatment Panel III (OR=1.49, 95% CI=1.42-1.56) and the International Diabetes Federation (OR=1.32, 95% CI=1.22-1.41) definitions. This relationship was independent of diabetes status. Moreover, all individual components of the MetS were significantly associated with CKD, and their coexistence resulted in an escalating dose-response relationship. The sensitivity and subgroup analyses established the stability of the findings. Conclusions: This meta-analysis strongly suggests that the metabolic syndrome and its components are independently associated with the increased risk of CKD.