At diagnosis of rheumatoid arthritis, anaemia and lymphopenia were associated with an increased risk of common infections (HR 1.37, 95% CI 1.08-1.73 and HR 1.18, 95% CI 1.08-1.29, respectively).
Cohort (n=6,591)
Yes
Do haematological abnormalities at diagnosis increase the risk of common infections in individuals with newly diagnosed rheumatoid arthritis?
In patients with newly diagnosed rheumatoid arthritis, baseline anaemia and lymphopenia are associated with an increased risk of common infections, while influenza vaccination is effective in reducing influenza-like illness.
Hazard Ratio: 1.37 (95% CI 1.08–1.73)
OBJECTIVES: To describe the prevalence of haematological abnormalities in individuals with RA at the point of diagnosis in primary care and the associations between haematological abnormalities, vaccinations and subsequent risk of common infections. METHODS: We studied 6591 individuals with newly diagnosed RA between 2004 and 2016 inclusive using the UK Royal College of General Practitioners Research and Surveillance Centre primary care database. The prevalence of haematological abnormalities at diagnosis (anaemia, neutropenia and lymphopenia) was established. Cox proportional hazards models were used to evaluate the association between each haematological abnormality and time to common infections and the influence of vaccination status (influenza and pneumococcal vaccine) on time to common infections in individuals with RA compared with a matched cohort of individuals without RA. RESULTS: Anaemia was common at RA diagnosis (16.1% of individuals), with neutropenia (0.6%) and lymphopenia (1.4%) less so. Lymphopenia and anaemia were associated with increased infection risk hazard ratio (HR) 1.18 (95% CI 1.08, 1.29) and HR 1.37 (95% CI 1.08, 1.73), respectively. There was no evidence of an association between neutropenia and infection risk HR 0.94 (95% CI 0.60, 1.47). Pneumonia was much more common in individuals with early RA compared with controls. Influenza vaccination was associated with reduced risk of influenza-like illness only for individuals with RA HR 0.58 (95% CI 0.37, 0.90). CONCLUSION: At diagnosis, anaemia and lymphopenia, but not neutropenia, increase the risk of common infections in individuals with RA. Our data support the effectiveness of the influenza vaccination in individuals with RA.
Nikiphorou et al. (2019) conducted a cohort in New-onset rheumatoid arthritis (n=6,591). Haematological abnormalities (anaemia and lymphopenia) vs. Absence of haematological abnormality was evaluated on Time to common infections (HR 1.37, 95% CI 1.08-1.73). At diagnosis of rheumatoid arthritis, anaemia and lymphopenia were associated with an increased risk of common infections (HR 1.37, 95% CI 1.08-1.73 and HR 1.18, 95% CI 1.08-1.29, respectively).