Temporal relationship between osteoarthritis and comorbidities: a combined case control and cohort study in the UK primary care setting

Abstract

Objective: To determine the burden of comorbidities in OA and their temporal relationships in the UK.

Methods: The Clinical Practice Research Datalink (CPRD) GOLD was used to identify people with incident OA and age, gender and practice matched non-OA controls from UK primary care. Controls were assigned the same index date as matched cases (date of OA diagnosis). Associations between OA and 49 individual comorbidities and multimorbidities (two or more comorbidities excluding OA) both before and after OA diagnosis were estimated, adjusting for covariates, using odds ratios (aORs) and hazard ratios (aHRs), respectively.

Results: During 1997-2017, we identified 221 807 incident OA cases and 221 807 matched controls. Of 49 comorbidities examined, 38 were associated with OA both prior to and following the diagnosis of OA and 2 (dementia and systemic lupus erythematosus) were associated with OA only following the diagnosis of OA. People with OA had a higher risk of developing heart failure [aHR 1.63 (95% CI 1.56, 1.71)], dementia [aHR 1.62 (95% CI 1.56, 1.68)], liver diseases [aHR 1.51 (95% CI 1.37, 1.67)], irritable bowel syndrome [aHR 1.51 (95% CI 1.45, 1.58)], gastrointestinal bleeding [aHR 1.49 (95% CI 1.39, 1.59)], 10 musculoskeletal conditions and 25 other conditions following OA diagnosis. The aOR for multimorbidity prior to the index date was 1.71 (95% CI 1.69, 1.74), whereas the aHR for multimorbidity after the index date was 1.29 (95% CI 1.28, 1.30).

Conclusions: People with OA are more likely to have other chronic conditions both before and after the OA diagnosis. Further study on shared aetiology and causality of these associations is needed.

Keywords: burden; comorbidity; multimorbidity; osteoarthritis; temporal association.

Fig. 1

Cumulative probabilities of developing additional multimorbidity in cases with OA and matched non-OA controls irrespective of any comorbidities at the index date

Fig. 2

Comparison of aORs and aHRs for comorbidities in OA for a maximum 20 years observation period (before and after index date) Red: both HR and OR significant; blue: only HR significant; purple: only OR significant; green: neither HR nor OR significant. Dashed black line represents statistical significance level at OR or HR = 1. Significant at P < 0.05 adjusted for multiple testing using FDR. Both the estimates were adjusted for age, sex, BMI, alcohol use, smoking, multimorbidity count at the index date.