Clinical effectiveness of influenza vaccination in patients with rheumatoid arthritis.

OBJECTIVE: To determine the clinical effectiveness of influenza vaccination in patients with rheumatoid arthritis (RA).

METHODS: The present study was conducted by using the Taiwan National Health Insurance Research Database. In this retrospective nationwide study, we included 3748 RA patients who received influenza vaccinations in 2008, 2009 and 2010, and 3748 matched RA patients who did not receive influenza vaccinations. We followed the patients from 4 weeks after influenza vaccination to the end of the influenza season in each year. After adjustment for potential confounding factors, including disease-modifying anti-rheumatic drugs, we used the Cox proportional hazards regression model to analyze the clinical effectiveness of influenza vaccination.

RESULTS: The influenza vaccination rate in RA patients was 14.8% in 2008, 19.8% in 2009 and 9.50% in 2010. Receiving influenza vaccine was associated with reduced risk of hospitalization for septicemia, bacteremia or viremia (hazards ratio [HR] = 0.65, 95% CI = 0.45-0.94), and lower risk of mortality (HR = 0.62, 95% CI = 0.39-0.97). The effectiveness was particularly significant in elderly patients.

CONCLUSIONS: RA patients receiving influenza vaccine have significantly lower morbidity and mortality, particularly in elderly patients. Further studies are needed to explore effective policies to increase the vaccination rate in elderly RA patients.