Immune thrombocytopenic purpura: epidemiology and implications for patients.

The age-adjusted prevalence of immune thrombocytopenic purpura (ITP) is estimated to be 9.5 per 100,000 persons in the USA while its annual incidence is estimated to be 2.68 per 100,000 in Northern Europe (at a cut-off platelet count of <100 x 10(9)/L). The mean age of adults at diagnosis in Europe is 50 yrs and the incidence of ITP increases with age. Both the treatments used to treat patients with ITP and the disease itself can impact on patient health-related quality of life (HRQoL). As the incidence of ITP in Europe rises, especially in the elderly, the number of patients with a decreased HRQoL is increasing. Literature searches and focus groups have aided the development of a conceptual model to assess HRQoL. In this model, low platelet counts and the associated symptoms of ITP in addition to the side effects of treatment are proposed as the main determinants of a negatively impacted HRQoL. Primary conceptual domains of HRQoL, affected in patients with ITP, include emotional health, functional health, work, social and leisure activities and reproductive health. As treatment benefits are likely to improve these domains, the conceptual model could be used for better management of patients, taking into account HRQoL. The short-form 36-item questionnaire (SF-36) and the ITP Patient Assessment Questionnaire (ITP-PAQ) are validated measures of HRQoL which can provide a comprehensive assessment of numerous factors to help evaluate decisions about patient management. Future clinical trials investigating treatment options for ITP should assess HRQoL using these validated questionnaires.