Schoonen WM, Kucera G, Coalson J, Li L, Rutstein M, Mowat F, Fryzek J, Kaye JA. 2009. Epidemiology of immune thrombocytopenic purpura in the General Practice Research Database. Br J Haematol 145(2):235-244.
The epidemiology of immune thrombocytopenic purpura (ITP) is not well‐characterised in the general population. This study described the incidence and survival of ITP using the UK population‐based General Practice Research Database (GPRD). ITP patients first diagnosed in 1990–2005 were identified in the GPRD. Overall incidence rates (per 100 000 person‐years) and rates by age, sex, and calendar periods were calculated. Survival analysis was conducted using the Kaplan‐Meier and proportional hazard methods. A total of 1145 incident ITP patients were identified. The crude incidence was 3·9 (95% confidence interval [CI]: 3·7–4·1). Overall average incidence was statistically significantly higher in women (4·4, 95% CI: 4·1–4·7) compared to men (3·4; 95% CI: 3·1–3·7). Among men, incidence was bimodal with peaks among ages under 18 and between 75–84 years. The hazard ratio for death among ITP patients was 1·6 (95% CI: 1·3–1·9) compared to age‐ and sex‐matched comparisons. During follow‐up 139 cases died, of whom 75 had a computerised plausible cause of death. Death was related to bleeding in 13% and infection in 19% of these 75. In conclusion, ITP incidence varies with age and is higher in women than men. This potentially serious medical condition is associated with increased mortality in the UK.