The Effect of Metabolic Syndrome and Its Individual Components on Renal Function: A Meta-Analysis

Background: Observational studies have reported inconsistent findings in the relationship between metabolic syndrome (MetS), its components, and loss of renal function, mainly including eGFR decline, new-onset CKD, and ESRD. This meta-analysis was performed to investigate their potential associations. Methods: PubMed and EMBASE were systematically searched from their inception to 21 July 2022. Observational cohort studies in English assessing the risk of renal dysfunction in individuals with MetS were identified. Risk estimates and their 95% confidence intervals (CIs) were extracted and pooled using the random-effects approach. Results: A total of 32 studies with 413,621 participants were included in the meta-analysis. MetS contributed to higher risks of renal dysfunction (RR = 1.50, 95% CI = 1.39–1.61) and, specifically, rapid decline in eGFR (RR 1.31, 95% CI 1.13–1.51), new-onset CKD (RR 1.47, 95% CI 1.37–1.58), as well as ESRD (RR 1.55, 95% CI 1.08–2.22). Moreover, all individual components of MetS were significantly associated with renal dysfunction, while elevated BP conveyed the highest risk (RR = 1.37, 95% CI = 1.29–1.46), impaired fasting glucose with the lowest and diabetic-dependent risk (RR = 1.20, 95% CI = 1.09–1.33). Conclusions: Individuals with MetS and its components are at higher risk of renal dysfunction.