Hidradenitis Suppurativa (HS) prevalence, demographics and management pathways in Australia: A population-based cross-sectional study

BACKGROUND: Hidradenitis Suppurativa (HS) is a painful, chronic inflammatory skin disease. Global estimates of prevalence vary between 0.03% and 4% of the population. Our main aim was to determine HS prevalence in the Australian adult population focussing on the demographics, management pathways and diagnosis rate of individuals living with HS. METHODS: In this population-based cross-sectional study, 17,050 individuals representative of the Australian adult population were asked through face-to-face household interviews to answer a previously validated HS screening questionnaire with high diagnostic power. Individuals who screened positive were asked additional questions, including previous diagnosis of HS and number/type of physicians consulted regarding their condition. RESULTS: 11,433 Australian residents answered the HS questionnaire, 88 screening positive for HS (0.77%; 95% CI 0.62–0.95). Considering the previously reported sensitivity (0.97) and positive predictive value (0.85) of the screening questionnaire, HS prevalence was estimated to be 0.67% (95% CI 0.53%-0.84%). 6 of 88 suspected HS individuals reported a pre-existing HS diagnosis (6.8%; 95% CI 3.2%-14.1%). 25.6% of the undiagnosed individuals suspected of having HS had not seen any clinicians regarding their boils; the remaining ones had consulted General Practitioners (96.7%), and clinicians from different specialties. Comparisons of individuals who screened positive for HS versus those who screened negative demonstrated statistically significant differences in gender (p = 0.0046), age (p<0.0001), BMI (p = 0.0307), smoking status (p<0.0001), employment status (p<0.0001) and income (p = 0.0321). CONCLUSIONS: The prevalence of HS in Australia was estimated to be 0.67% (95% CI 0.53%-0.84%). The diagnosis rate amongst the suspected HS cases was low, which appeared to be due to a combination of patients not seeking help and decentralization of care. Individuals suspected of having HS were more likely to be females, young, obese, smokers, unemployed or at home duties and having lower annual personal income in comparison with individuals not suspected of having HS.