Risk of hospitalised infection in rheumatoid arthritis patients receiving biologics following a previous infection while on treatment with anti-TNF therapy.

BACKGROUND

The risk of subsequent infections in rheumatoid arthritis (RA) patients who receive biologic therapy after a serious infection is unclear.

OBJECTIVE

To compare the subsequent risk of hospitalised infections associated with specific biologic agents among RA patients previously hospitalised for infection while receiving anti-tumour necrosis factor (anti-TNF) therapy.

METHODS

Using 2006-2010 Medicare data for 100% of beneficiaries with RA enrolled in Medicare, we identified patients hospitalised with an infection while on anti-TNF agents. Follow-up began 61 days after hospital discharge and ended at the earliest of: next infection, loss of Medicare coverage or 18 months after start of follow-up. We calculated the incidence rate of subsequent hospitalised infection for each biologic and used Cox regression to control for potential confounders.

RESULTS

10 794 eligible hospitalised infections among 10183 unique RA patients who contributed at least 1 day of biologic exposure during follow-up. We identified 7807 person-years of exposure to selected biologics--333 abatacept, 133 rituximab and 7341 anti-TNFs (1797 etanercept, 1405 adalimumab, 4139 infliximab)--and 2666 associated infections. Mean age across biologic exposure cohorts was 64-69 years. The crude incidence rate of subsequent hospitalised infection ranged from 27.1 to 34.6 per 100 person-years. After multivariable adjustment, abatacept (HR: 0.80, 95% CI 0.64 to 0.99) and etanercept (HR: 0.83, 95% CI 0.72 to 0.96) users had significantly lower risks of subsequent infection compared to infliximab users.

CONCLUSIONS

Among RA patients who experienced a hospitalised infection while on anti-TNF therapy, abatacept and etanercept were associated with the lowest risk of subsequent infection compared to other biologic therapies.