Severe adverse drug reactions to biological disease-modifying anti-rheumatic drugs in elderly patients with rheumatoid arthritis in clinical practice.

OBJECTIVES: Biological DMARDs are widely used in the treatment of rheumatoid arthritis (RA) but their relationship with adverse drug reaction (ADR) is important. RA is now known to increase in incidence and prevalence with age. Our objective was to assess the incidence of severe ADR in the long term, compare safety between the different bDMARDs and identify other possible risk factors for severe ADR in elderly RA patients.

METHODS: A 14-year retrospective longitudinal study was performed. RA patients followed in an out-patient clinic starting bDMARDs after the age of 65 were included.

PRIMARY OUTCOME: discontinuation due to a severe ADR related to bDMARDs (etanercept, infliximab, adalimumab, rituximab, golimumab, certolizumab, abatacept and tocilizumab). Covariables: sociodemographic, clinical and therapy. Incidence rates of discontinuation were estimated using survival techniques and comparison between bDMARDs discontinuation rates and other associated factors were run by Cox regression models.

RESULTS: We analysed 286 courses of bDMARDs therapy in 146 elderly patients (604 patient-years). 78% were women, with a mean age at diagnosis of 66.5±7 years, and a median time to the start of the first bDMARDs of 6±4 years. The incidence of discontinuation due to severe ADR estimated was 10.2% patient-years, with a median survival of around 7 years. The most frequent cause was infections. Etanercept had the lowest risk of severe ADR compared to other bDMARDs.

CONCLUSIONS: Our study reflects the 'real world' experience in elderly RA patients on bDMARDs, with non-selected patients for a 14-year follow-up.