Epidemiology

Over time, PAN has become progressively less common, largely owing to effective hepatitis B virus (HBV) immunization programs and improved blood screening for HBV, as well as to major alterations in the definition and classification of vasculitis. Before the Chapel Hill Consensus Conference (CHCC) definition in 1994, microscopic polyangiitis was included in the incidence and prevalence estimates. The impact of this is highlighted in a study comparing the incidence of PAN in 3 European regions: 4.4-9.7 per million by the American College of Rheumatology (ACR) criteria compared with 0-0.9 per million with the CHCC definition.[10]

The incidence of PAN is between 2 and 9 per million/year in Europe and the US by the ACR criteria.[11] Higher incidences have been reported in some populations: 16 per million/year in Kuwait (by CHCC definition)[12] and 77 per million/year in an Alaskan population in which HBV infection is endemic (in a study that predates the ACR criteria and the CHCC definition).[13] The prevalence of PAN by the ACR criteria is between 31 and 33 per million in western Europe and, by the CHCC definition, is between 2 and 9 per million in Germany.[14][15][16][17] An observational study, between the years 1990 to 2015, reported a decrease in the frequency of PAN after 2010. This was attributed to improvements in healthcare and refinements in classification, allowing more accurate discrimination between PAN and similar conditions.[18]

PAN can occur at any age, but the most common age at diagnosis is 40 to 60 years. There is no clear sex difference, although most case series report a slight preponderance of males.[15][18][19][20] However, a prevalence estimate in Sweden in 2007 reported the opposite, with two-thirds of the patients being female.[16] In a multiethnic population in Paris, those with European ancestry had a higher prevalence of PAN.[15]

Use of this content is subject to our disclaimer