Bidirectional association between metabolic syndrome and osteoarthritis: a meta-analysis of observational studies

Emerging observational studies suggest an association between metabolic syndrome (MetS) and osteoarthritis (OA). This meta-analysis was conducted to examine whether or not there is a bidirectional relationship between MetS and OA. The PubMed and Embase databases were searched from their inception to October 2019. We selected studies according to predefined criteria. Random effects were selected to calculate two sets of pooled risk estimates: MetS predicting OA and OA predicting MetS. A total of seven cross-sectional studies and four cohort studies met the criteria for MetS predicting the onset of OA. Another six cross-sectional studies and one cohort study met the criteria for OA predicting the onset of MetS. The pooled odds risk (OR) for OA incidences associated with baseline MetS was 1.45 (95% CI 1.27–1.66). The OR for MetS incidences associated with baseline OA was 1.90 (95% CI 1.11–3.27). In an overall analysis, we found that MetS was associated with prevalent OA in both cross-sectional studies (OR = 1.32, 95% CI 1.21–1.44) and cohort studies (OR = 1.76, 95% CI 1.29–2.42). No indication of heterogeneity was found in the cross-sectional studies (p = 0.395, I2 = 4.8%), whereas substantial heterogeneity was detected in the cohort studies (p = 0.000, I2 = 79.3%). Meta-analysis indicated a bidirectional association between MetS and OA. We advise that patients with MetS should monitor their OA status early and carefully, and vice versa.