Comorbidities in Osteoarthritis: A systematic review and meta-analysis of observational studies.
Osteoarthritis (OA) is a common chronic condition in older people but its association with other chronic conditions is largely unknown. This study aimed to systematically review the literature on comorbidities in people with OA compared to those without. We searched four databases for observational studies on comorbidities in people with OA. Studies of OA only or in comparison with non-OA controls were included. Risk of bias and study quality was assessed using the Newcastle-Ottawa Scale (NOS). The prevalence of comorbidities in the OA group and prevalence ratio (PR) and 95% confidence interval (CI) between OA and non-OA groups were calculated. Forty-two studies from 16 countries (27 case-only and 15 comparative studies) met the inclusion criteria. Mean age of participants varied from 51 to 76 years. Pooled prevalence of any comorbidity was 67% (95%CI: 57%-74%) in people with OA versus 56% (95%CI: 44%-68%) in people without OA. The pooled PR for any comorbidity was 1.21 (95%CI: 1.02-1.45). The PR increased from 0.73 (95%CI: 0.43-1.25) for one comorbidity, to 1.58 (95%CI: 1.03-2.42) for two, and 1.94 (95%CI 1.45- 2.59) for three or more comorbidities. The key comorbidities associated with OA were stroke (PR 2.61; 95%CI: 2.13-3.21), peptic ulcer (PR 2.36; 95%CI: 1.71-3.27) and metabolic syndrome (PR 1.94; 95%CI 1.21-3.12). People with OA are more likely to have other chronic conditions. The association is dose-dependent in terms of the number of comorbidities, suggesting multimorbidities. Further studies on the causality of this association and clinical implications are needed. This article is protected by copyright. All rights reserved.