Population‐based Clinical Practice Research Datalink study using algorithm modelling to identify the true burden of hidradenitis suppurativa

摘要

Summary Background Epidemiology data regarding hidradenitis suppurativa (HS ) are conflicting and prevalence estimates vary 80fold, from 0?5% in a populationbased study to 4%.Objectives To assess the hypothesis that previous populationbased studies underestimated trueHS prevalence by missing undiagnosed cases.Methods We performed a populationbased observational and casecontrol study using the U.K. Clinical Practice Research Datalink (CPRD ) linked to hospital episode statistics data. Physiciandiagnosed cases in theCPRD were identified from specific Read codes. Algorithms identified unrecognized proxy cases, with at least five Read code records for boils in flexural skin sites. Validation of proxy cases was undertaken with general practitioner (GP ) questionnaires to confirm criteriadiagnosed cases. A casecontrol study assessed disease associations.Results On 30 June 2013, 23 353 physiciandiagnosedHS cases were documented in 4 364 308 researchstandard records. In total, 68 890 proxy cases were identified, reduced to 10 146 criteriadiagnosed cases after validation, extrapolated from 107 completed questionnaires (61% return rate). Overall point prevalence was 0?7% [95% confidence interval (CI ) 0?60?8%]. An additional 18 417 cases had a history of one to four flexural skin boils. In physiciandiagnosed cases, odds ratios (OR s) for current smoker and obesity (body mass index 30 kg m2 ) were 3?1 (95%CI 3?43?9) and 3?9 (95%CI 3?43?5).HS was associated with type 2 diabetes, Crohn disease, hyperlipidaemia, acne and depression, and not associated with ulcerative colitis or polycystic ovary syndrome.Conclusions Contrary to results of previous populationbased studies,HS is relatively common, with a U.K. prevalence of 0?7%, onethird being unrecognized, criteriadiagnosed cases using the most stringent disease definition. If individuals with probable cases are included,HS prevalence rises to 1?9%.