Background Gout is the most common cause of inflammatory arthritis in men and older women, and there are very few studies on the rate of joint replacement among patients with diagnosed gout compared to those without gout.
Objectives To assess the risk of joint replacement among patients with diagnosed gout compared to patients without gout diagnosis, and the predictors.
Methods This was a population-based study with cohort study design in a cohort of older adults. We first identified all subjects aged >66 years between January 1, 1995 and December 31, 2009. A study cohort of 252,255 individuals was reconstructed using the Quebec RAMQ and MedEcho administrative databases. Patients with gout diagnosis were defined only if they met all of the following criteria: 1) gout defined by ICD-9 or ICD-10 or exposure of specific gout treatment. The date of cohort entry of patients with gout was defined as the first date of established gout during follow-up. The primary outcome was incident joint replacement rate defined by a composite endpoint representing patients with a medical procedure in the hip, femur and basin, knee, ankle/foot, hand/finger, shoulder and humerus, forearm and elbow, or wrist. Potential predictive factors examined included gout diagnosis, cardiovascular diseases, cerebrovascular disease, peripheral vascular disease, diabetes, kidney disease, pulmonary disease, dementia, rheumatic disease, and gastrointestinal disease.
Results The incident rate of joint replacements was at 2.67 (95% CI: 2.57–2.77) and 1.92 (1.90–1.94) per 100 person-years among patients with diagnosed gout and those without a gout diagnosis, respectively (p<0.0001). Major predictors of total joint replacements were gout diagnosis (31%), advanced age (42%), cerebrovascular disease (13%), acute renal failure (10%), respiratory disease (12%), rheumatic disease (43%), and gastrointestinal disease (10%). Significant predictors of drug exposure are NSAIDs, intra-articular corticosteroids and narcotic use. Noted limitations included the limited ability to adjust for clinical severity and the potential of residual confounding factors.
Conclusions Gout disease was associated with a significant, 31% increase risk of joint replacement in older adults. Further research should be conducted to confirm this potential associated risk.
Acknowledgement This study was funded by AstraZeneca.
Disclosure of Interest S. Perreault: None declared, A. Klein Employee of: AstraZeneca, R. Morlock Employee of: Ardea Biosciences, Inc., a member of the AstraZeneca Group