AB0235 THE LIFETIME RISK OF KNEE AND HIP REPLACEMENT FOLLOWING A DIAGNOSIS OF RHEUMATOID ARTHRITIS: FINDINGS FROM ROUTINELY COLLECTED DATA FROM ENGLAND
Authors: Edward Burn, Christopher Edwards, David W. Murray, Alan Silman, Cyrus Cooper, Nigel Arden, Rafael Pinedo-Villanueva, Daniel Prieto-Alhambra
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Understanding the lifetime risk of knee and hip replacement following a diagnosis of rheumatoid arthritis (RA) would help provide patients and clinicians with an indication of long-term prognosis and future health care utilisation. <h3>Objectives</h3> To estimate the lifetime risk of knee and hip replacement following a diagnosis of RA. <h3>Methods</h3> Routinely collected data from the English NHS was used to inform the analysis. Diagnosis of RA was identified using primary care records, with knee and hip replacement observed in linked hospital records. Parametric survival models were fitted for up to 15 years of follow up, with age, sex, Charlson comorbidity score, socioeconomic status, BMI, and smoking status included as explanatory variables. A decision model was used to combine and extrapolate survival models to estimate lifetime risk. Lifetime risk was estimated for individuals with average characteristics (median for continuous variables and mode for categorical ones). The partial effect of explanatory factors on lifetime risk was assessed by re-running models with participant profiles varying in the explanatory factor of interest, while holding other characteristics constant at their average. <h3>Results</h3> 13,961 study participants with a diagnosis of RA were included. Lifetime risk of knee replacement and hip replacement was estimated to be 22% (95%CI 16% to 29%) and 17% (11% to 26%) following a diagnosis of RA for the average patient profile (non-smoking women aged 64 with no other comorbidities, BMI of 27 and in the top socioeconomic quintile). Risks were higher for younger patients, but broadly similar for men and women. Comorbidities, socioeconomic status, BMI, and smoking status had relatively little impact on lifetime risk. <h3>Conclusion</h3> This study has estimated lifetime risk of knee and hip replacement following a diagnosis of RA, allowing for a better understanding of long-term prognosis and healthcare resource use. These risks are more than double those of the general UK population. <h3> Disclosure of Interests</h3> Edward Burn: None declared, Christopher Edwards Grant/research support from: Abbvie, BMS, Biogen, Celgene, Fresenius, Janssen, Lilly, Mundipharma, Pfizer, MSD, Novartis, Roche, Samsung, Sanofi, UCB, Consultant for: Abbvie, BMS, Biogen, Celgene, Fresenius, Janssen, Lilly, Mundipharma, Pfizer, MSD, Novartis, Roche, Samsung, Sanofi, UCB, Speakers bureau: Abbvie, BMS, Biogen, Celgene, Fresenius, Janssen, Lilly, Mundipharma, Pfizer, MSD, Novartis, Roche, Samsung, Sanofi, UCB, David W Murray Grant/research support from: Grants from Zimmer Biomet, Consultant for: Personal fees from Zimmer Biomet, Alan Silman: None declared, Cyrus Cooper Consultant for: Personal fees from Alliance for Better Bone Health, Amgen, Eli Lilly, GSK, Medtronic, Merck, Novartis, Pfizer, Roche, Servier, Takeda and UCB., Nigel Arden Grant/research support from: Grants from BIOIBERICA, and from MERCK., Consultant for: Personal fees from Flexion, from Regeneron, from Freshfields Bruckhaus Deringer, outside the submitted work., Rafael Pinedo-Villanueva: None declared, Daniel Prieto-Alhambra Grant/research support from: Grants from Amgen, UCB Biopharma and Servier outside the submitted work, Consultant for: UCB Biopharma, Speakers bureau: Amgen