The epidemiology of Takayasu arteritis in the UK.

OBJECTIVES Takayasu arteritis (TAK) is a large-vessel vasculitis of unknown aetiology. The annual incidence in hospital-based studies is 1-2/million. The UK General Practice Research Database (UKGPRD) contains complete primary care records on 3.6 million people. There are no data on the incidence of TAK in the UK or from primary care anywhere in the world. The aim of this study was to determine the annual incidence of TAK in the UK using the UKGPRD and in a well-defined hospital population [Norfolk Vasculitis Register (NORVASC)]. METHODS We identified all patients in the UKGPRD with a first diagnosis of TAK during 2000-05, using the Read code (G757); and in the NORVASC population. The annual incidence was calculated as the number of incident cases divided by total person-years. RESULTS A total of 14 (13 females) subjects were identified with a first diagnosis of TAK during 2000-05 in the UKGPRD. The median age was 51.0 years (interquartile range 28-66). The overall annual incidence of TAK was 0.8/million (95% CI 0.4, 1.3). The incidence was stable throughout the study period. The mean prevalence of TAK was 4.7/million. There were six patients (five females) aged <40 years presenting in 2000-05 with TAK. The annual incidence in those aged <40 years was 0.3/million. In the NORVASC population, one case was identified (0.4/million/year) with three prevalent cases (7.1/million). CONCLUSION This is the first population-based study of the epidemiology of TAK. The annual incidence and prevalence are consistent with previous studies.