Comorbidities in Osteoarthritis: A Systematic Review and Meta‐Analysis of Observational Studies

Abstract

ObjectiveOsteoarthritis (OA) is a common chronic condition in older individuals, but its association with other chronic conditions is largely unknown. This study aimed to systematically review the literature on comorbidities in individuals with OA compared to those without.MethodsWe searched 4 databases for observational studies on comorbidities in individuals with OA. Studies of OA only or in comparison with non‐OA controls were included. The risk of bias and study quality were assessed using the Newcastle‐Ottawa Scale. The prevalence of comorbidities in the OA group and the prevalence ratio (PR) and 95% confidence interval (95% CI) between OA and non‐OA groups were calculated.ResultsIn all, 42 studies from 16 countries (27 case‐only and 15 comparative studies) met the inclusion criteria. The mean age of participants varied from 51 to 76 years. The pooled prevalence of any comorbidity was 67% (95% CI 57–74) in individuals with OA versus 56% (95% CI 44–68) in individuals 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 1 comorbidity to 1.58 (95% CI 1.03–2.42) for 2, and to 1.94 (95% CI 1.45–2.59) for ≥3 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]).ConclusionIndividuals 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.

Multimorbidity and risk of falls, fractures, and joint replacements over two decades: Findings from the Hertfordshire Cohort Study

“…The link between OA and multimorbidity is well established, and a previous systematic review and meta-analysis suggested that multimorbidity is more common among participants with OA than among those without, such that individuals with OA are 1.2 times more likely to have any comorbidity than non-OA controls and 2.5 times more likely to have ≥3 comorbidities. 20 Hence our results accord with this. The authors of the systematic review thoughtfully considered the limitations in their analysis, including heterogeneity in study design, and some concerns about coding of comorbidity and OA.…”

Multimorbidity and risk of falls, fractures, and joint replacements over two decades: Findings from the Hertfordshire Cohort Study

“…The link between OA and multimorbidity is well established, and a previous systematic review and meta-analysis suggested that multimorbidity is more common among participants with OA than among those without, such that individuals with OA are 1.2 times more likely to have any comorbidity than non-OA controls and 2.5 times more likely to have ≥3 comorbidities. 20 Hence our results accord with this. The authors of the systematic review thoughtfully considered the limitations in their analysis, including heterogeneity in study design, and some concerns about coding of comorbidity and OA.…”

Health status of individuals referred to first-line intervention for hip and knee osteoarthritis compared with the general population: an observational register-based study

“…Despite these circumstances, we could identify a higher prevalence of several diseases in the OA population compared with the age-matched, sex-matched and residence-matched reference cohort. The results from the present study are applicable on OA individuals referred to first-line intervention, but are also in line with several previous studies,4 5 48 describing comorbidities among individuals with OA compared with general populations.…”

Clinical phenotypes of comorbidities in end-stage knee osteoarthritis: a cluster analysis

“…This may be related to the inclusion of our study population in the end-stage of knee osteoarthritis, as age is a strong correlate of the prevalence of most chronic diseases, and the onset of chronic disease is associated with its accumulation of temporal exposure to associated risk factors and changes in the declining function of the body. Furthermore, with regard to the most common comorbidities, our results were similar to other previously published cohort studies in that psychological disorders, cardiovascular disorders and metabolic syndrome comorbidities were the most common, with the exception of liver disease [ 9 , 20 ]. We believe that the reason for the high proportion of liver disease is related to the definition describing this comorbidity, with the highest proportion of liver diseases in our cohort being non-alcoholic fatty liver disease, which has a high clinical prevalence and a high number of co-pathogenic factors with end-stage KOA [ 22 ].…”

Multimorbidity and risk of falls, fractures, and joint replacements over two decades: Findings from the Hertfordshire Cohort Study

“…The link between OA and multimorbidity is well established, and a previous systematic review and meta-analysis suggested that multimorbidity is more common among participants with OA than among those without, such that individuals with OA are 1.2 times more likely to have any comorbidity than non-OA controls and 2.5 times more likely to have ≥3 comorbidities. 20 Hence our results accord with this. The authors of the systematic review thoughtfully considered the limitations in their analysis, including heterogeneity in study design, and some concerns about coding of comorbidity and OA.…”

Health status of individuals referred to first-line intervention for hip and knee osteoarthritis compared with the general population: an observational register-based study

“…Despite these circumstances, we could identify a higher prevalence of several diseases in the OA population compared with the age-matched, sex-matched and residence-matched reference cohort. The results from the present study are applicable on OA individuals referred to first-line intervention, but are also in line with several previous studies,4 5 48 describing comorbidities among individuals with OA compared with general populations.…”

Clinical phenotypes of comorbidities in end-stage knee osteoarthritis: a cluster analysis

“…This may be related to the inclusion of our study population in the end-stage of knee osteoarthritis, as age is a strong correlate of the prevalence of most chronic diseases, and the onset of chronic disease is associated with its accumulation of temporal exposure to associated risk factors and changes in the declining function of the body. Furthermore, with regard to the most common comorbidities, our results were similar to other previously published cohort studies in that psychological disorders, cardiovascular disorders and metabolic syndrome comorbidities were the most common, with the exception of liver disease [ 9 , 20 ]. We believe that the reason for the high proportion of liver disease is related to the definition describing this comorbidity, with the highest proportion of liver diseases in our cohort being non-alcoholic fatty liver disease, which has a high clinical prevalence and a high number of co-pathogenic factors with end-stage KOA [ 22 ].…”

Multimorbidity and risk of falls, fractures, and joint replacements over two decades: Findings from the Hertfordshire Cohort Study

“…The link between OA and multimorbidity is well established, and a previous systematic review and meta-analysis suggested that multimorbidity is more common among participants with OA than among those without, such that individuals with OA are 1.2 times more likely to have any comorbidity than non-OA controls and 2.5 times more likely to have ≥3 comorbidities. 20 Hence our results accord with this. The authors of the systematic review thoughtfully considered the limitations in their analysis, including heterogeneity in study design, and some concerns about coding of comorbidity and OA.…”

Health status of individuals referred to first-line intervention for hip and knee osteoarthritis compared with the general population: an observational register-based study

“…Despite these circumstances, we could identify a higher prevalence of several diseases in the OA population compared with the age-matched, sex-matched and residence-matched reference cohort. The results from the present study are applicable on OA individuals referred to first-line intervention, but are also in line with several previous studies,4 5 48 describing comorbidities among individuals with OA compared with general populations.…”

Clinical phenotypes of comorbidities in end-stage knee osteoarthritis: a cluster analysis

“…This may be related to the inclusion of our study population in the end-stage of knee osteoarthritis, as age is a strong correlate of the prevalence of most chronic diseases, and the onset of chronic disease is associated with its accumulation of temporal exposure to associated risk factors and changes in the declining function of the body. Furthermore, with regard to the most common comorbidities, our results were similar to other previously published cohort studies in that psychological disorders, cardiovascular disorders and metabolic syndrome comorbidities were the most common, with the exception of liver disease [ 9 , 20 ]. We believe that the reason for the high proportion of liver disease is related to the definition describing this comorbidity, with the highest proportion of liver diseases in our cohort being non-alcoholic fatty liver disease, which has a high clinical prevalence and a high number of co-pathogenic factors with end-stage KOA [ 22 ].…”