Prevalence of Hidradenitis Suppurativa: A Meta-Analysis of Global Hidradenitis Suppurativa Atlas Studies.

Importance: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a substantial burden. Standardized global prevalence estimates and data on associated sociodemographic and risk factors are lacking. Objective: To estimate the global prevalence of HS and study differences in prevalence by age, sex, geographical location, body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), smoking status, gross domestic product (GDP), and Human Development Index (HDI). Data Sources and Study Selection: Included studies were conducted using the standardized Global Hidradenitis Suppurativa Atlas methodology with finalized data collection before May 19, 2023. Studies were required to use a population-based sampling method and conduct clinical confirmation of HS diagnosis following a screening questionnaire. Data Extraction and Synthesis: Data were independently extracted from relevant studies by 2 reviewers (D.B. and C.E.M.) using a standardized form. Extracted variables included geographic location, age, sex, BMI (median and BMI >30), smoking status, HS prevalence estimates (with 95% CIs), GDP, and HDI. A proportional meta-analysis using a random-effects model was conducted on the included studies. Main Outcomes and Measures: The primary outcome was the point prevalence of HS, confirmed by clinical examination. Secondary outcomes included differences in HS prevalence by sex, age, BMI category, smoking status, and country-level socioeconomic indicators (GDP and HDI). All outcomes were prespecified before data analysis. Results: The sample included 22 743 participants, identifying 247 patients with HS, across 25 studies in 23 countries spanning 6 continents. The median proportion of female patients with HS was 55.6%, and the median age was 34.5 years. While the prevalence estimates showed considerable inconsistency (I2 > 75%; τ2 = 0.747), the overall random-effects global prevalence of HS was 0.99% (95% CI, 0.67%-1.46%). Female sex was the only factor observed to be associated with the prevalence estimates (β = 1.02; 95% CI, 1.01-1.03). Conclusions and Relevance: In this meta-analysis, an estimated global prevalence of HS between 0.67% and 1.46% surpassed previous global estimates. Substantial global variations in HS prevalence were also observed. Female sex was the only factor associated with prevalence in this sample. Future studies assessing genetic, environmental, and etiological factors are warranted to explain the heterogeneity in prevalence.