Lifetime Risk of Knee and Hip Replacement Following a Diagnosis of RA

Findings From a Cohort of 13 961 Patients From England

Edward Burn; Christopher J. Edwards; David W. Murray; Alan Silman; Cyrus Cooper; Nigel K. Arden; Rafael Pinedo-Villanueva; Daniel Prieto-Alhambra


Rheumatology. 2019;58(11):1950-1954. 

In This Article

Abstract and Introduction


Objective: To estimate the lifetime risk of knee and hip replacement following a diagnosis of RA.

Methods: The analysis was undertaken using routinely collected data from the English NHS. 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.

Results: The number of individuals with a diagnosis of RA and included in the study was 13 961. Lifetime risk of knee replacement and hip replacement was estimated to be 22% (95% CI: 16, 29%) and 17% (95% CI: 11, 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.

Conclusion: The lifetime risk of knee and hip replacement for individuals with a diagnosis of RA is approximately double that of the general population. These findings allow for a better understanding of long-term prognosis and healthcare resource use, and highlight the importance of timely diagnosis and effective treatment.


RA is characterized by persistent synovitis and systemic inflammation and can lead to the progressive destruction and secondary osteoarthritis of both small and large joints. Surgical procedures may help to relieve pain, maintain or restore function, correct deformity or instability, and prevent or treat failure of structures. Knee and hip replacement are two of the most common surgeries for individuals with RA.[1]

There have been substantial advances in management of RA over recent decades, with numerous effective disease modifying agents introduced coupled with improvements in both diagnostic and management strategies. Likely as a result, while rates of knee and hip replacement have been increasing over recent years in the general population,[2–4] rates among those with RA have remained relatively stable.[5]

Fifty-year-old men and women from the general population in the UK have an 8 and 11% lifetime risk of knee replacement and a 7 and 11% risk of hip replacement, respectively.[6] Risks are lower for older individuals with, for example, 80-year-olds having a 3–4% lifetime risk of knee and hip replacement.[6] It is not known whether the improvements in the management of RA have led to this risk being reduced to that of the general population, or whether there remains an increased risk of knee and hip replacement for individuals with RA.

Understanding the lifetime risk of knee and hip replacement following a diagnosis of RA would help provide patients and clinicians with an indication of long-term prognosis and future health care utilization. Therefore, in this study we estimated the lifetime risks of knee and hip replacement following a diagnosis of RA and the effect of patient characteristics at time of diagnosis on this risk.