Presentation: The Incidence of Wegener's Granulomatosis and Churg Strauss Syndrome in the UK General Practice Database (2007)

2017 The Incidence of Wegener's Granulomatosis and Churg Strauss Syndrome in the UK General Practice Database

Purpose: The ANCA-associated vasculitides Wegener’s granulomatosis (WG) and Churg Strauss Syndrome (CSS) are conditions of unknown aetiology predominately affecting those aged >60 years. They are rare conditions, obtaining accurate estimates of their occurrence in populations is difficult and requires large scale population surveillance using methods of case ascertainment that are consistent over time. The aim of this study was to investigate the incidence of WG and CSS over the period 2000-05 using population data from the UK General Practice Database (UKGPRD) which provides complete electronic data collected from family practices on the health records of approximately 2.8 million patients in the UK, a representative sample of the UK population.
Methods: Cases were defined as those with a first diagnosis of WG, and CSS entered into the general practice record during the period 2000-2005. Entry date was considered as the date at which a first diagnosis of WG was given. GPRD records for patients with a diagnosis of WG were identified using Oxford Information System and Read codes specific for Wegener’s granulomatosis or Wegener Syndrome (OXMIS 4462W, 4462WG and Read G754.00). Similarly records for patients with a diagnosis of CSS were identified using Read codes (G758.00). The annual incidence of diagnosed WG or CSS was defined as the number of patients first diagnosed with WG or CSS in the years 2000-05 divided by the total number of patients registered in each year.
Results: A total of 155 (54.8% male) with a first diagnosis of WG were identified in the study period. The mean age (mean ± SD) for this group of patients at the first diagnosis was 57.7±15.7 years. The overall annual incidence of WG in 2000 to 2005 was 8.03/million (95% CI, [6.77 to 9.30]). The rate among females was 7.16 (95% CI; [5.48 to 8.83]) and in males 8.94 (95% CI: [7.04 to 10.84]). In the same study period, 49 cases of CSS were identified (49% male). The average age was 54.8±12.4 years for this group of patients. The overall incidence for CSS was 2.54/million (95% CI, [1.83 to 3.25]). The rate among females was 2.56 (95% CI: [1.55 to 3.56]) and males was 2.52 (95%CI: [1.53 to 3.51]). The annual incidence of both WG and CSS showed no significant change during the study period.
Discussion: This is the first study of the incidence of WG and CSS from a primary care population. Other population based studies have been based on hospital admission statistics and not primary care records. Our data is consistent with a recent Swedish study based on national hospital discharge statistics which reported an incidence of 7.8/million for WG (1) Accurate population based incidence figures are important for planning health care provision as these conditions are associated with significant morbidity and mortality, and high associated treatment costs.
1. Knight et al J Rheumatol 2006;33:2060.

 R. Watts, None; A. Al-Taiar, None; J. Skinner, None; D. Scott, None; A. MacGregor, None.