Infections in non‐splenectomized persistent or chronic primary immune thrombocytopenia adults: risk factors and vaccination effect

Essentials The risk factors for infection in immune thrombocytopenia are not well known. We conducted a national pharmacoepidemiological study. Pulmonary disease, corticosteroids and rituximab were the main risk factors for infections. Pneumococcal and influenza vaccines were protective against infections. Summary Introduction Risk factors for infection and protective effect of vaccines in immune thrombocytopenia (ITP) patients in the era of rituximab therapy are unknown. Objectives To assess the risk factors for serious and non‐serious infections (respectively, SIs and NSIs) in non‐splenectomized adults treated for persistent or chronic primary ITP, including the effect of pneumococcal and influenza vaccines. Patients/Methods The population was the 2009–2012 FAITH cohort (n = 1805), which is the cohort of all incident (newly diagnosed) primary ITP adults treated > 3 months in France built into the national health insurance database (SNIIRAM). SIs were hospitalizations with any infection as the primary diagnosis code. NSIs were identified using out‐of‐hospital antibiotic dispensing. Cox models were performed. Results Incidence rates were 6.3/100 patient‐years (95% confidence interval [CI], 5.4–7.4) for SIs (lower respiratory tract in 42.8% of the cases) and 100.5/100 patient‐years (95% CI, 95.0–106.3) for NSIs. In multivariate analyses, increasing age and chronic pulmonary disease were associated with both SI and NSI occurrence. The hazard ratios (HRs) for corticosteroids and rituximab were, respectively, 3.83 (95% CI, 2.76–5.31) and 2.60 (95% CI, 1.67–4.03) for SIs and 2.46 (95% CI, 2.19–2.76) and 1.49 (95% CI, 1.28–1.74) for NSIs. Pneumococcal vaccine showed a protective effect for both SIs and NSIs (0.38 [95% CI, 0.20–0.73] and 0.52 [95% CI, 0.43–0.65], respectively), as did influenza vaccine (0.42 [95% CI, 0.27–0.64] and 0.49 [95% CI, 0.41–0.59], respectively). Conclusions Chronic pulmonary disease, corticosteroids and rituximab are the main risk factors for infections, whereas pneumococcal and influenza vaccines are protective against SIs and NSIs.