Abstract
Background
Patients with rheumatoid arthritis (RA) are at an increased risk of infection. Most attention has been given to serious infections, but these are the tip of the iceberg. Non-serious infections (NSI) are far more frequent, and although not life-threatening, have potential to impact treatment outcomes (drug survival) and quality of life. Our objective was to describe frequency of NSI and compare incidence of NSI by biologic drug within the British Society for Rheumatology Biologics Register (BSRBR-RA).
Methods
The BSRBR-RA is a prospective observational cohort study. NSI was identified as not requiring hospitalisation, intravenous therapy or leading to disability or death. Infections were captured from clinician questionnaires and patient diaries. Individuals were considered ‘at risk’ from the date of commencing biologic treatment for 3 years. Drug exposure was defined by agent; TNF inhibitor, IL-6 inhibitor, anti-CD20 or csDMARD only. To account for a high frequency of events, a multiple-failure Cox model was used. Multivariable adjustment included age, gender, DAS28-ESR, HAQ-DI, disease duration, smoking, steroid usage, year recruited to BSRBR-RA, line of biologic therapy and cumulative infection number.
Results
There were 17,304 NSI in 10,099 patients, with an event rate of 27.0 per year (95% CI 26.6 to 27.4). Increasing age, female gender, comorbidity burden, corticosteroid therapy, DAS28 and HAQ-DI were associated with an increased risk of NSI. The rate of NSI was numerically lowest with csDMARDs. Compared to TNFi, IL-6 inhibitor had a higher risk of NSI, whilst the csDMARD cohort had a lower risk. Between the TNFi agents, adalimumab had a higher risk than etanercept (Table 1).
Conclusion
These results confirm that NSI is a frequent occurrence for patients, which historically has received little attention in research literature. The data suggest biologics increase the risk of NSI, especially IL-6 inhibition. Whilst unmeasured confounding must be considered, the magnitude of effects are large and it seems likely that a causal link between targeted immunosuppression and NSI risk exists. Further research is needed to understand the impact of NSI on clinical outcomes including drug survival and quality of life.
Disclosures
K. Bechman: None. K. Halai: None. S. Norton: None. A.P. Cope: None. K.L. Hyrich: Honoraria; AbbVie paid to the institution and grant income from Pfizer and Bristol-Myers Squibb for activities outside of this work. J.B. Galloway: Honoraria; for speaking or attending conferences from AbbVie, Bristol-Myers Squibb, Celgene, Janssen, Pfizer and Union Chimique Belge.
186 Quality of life estimation in economic evaluations and healthcare decision making: different approaches, different results. Results from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS)
