It’s a Numbers Thing

HS prevalence study may help drive funding for better disease diagnosis

According to a new systematic review and meta-regression analysis, the worldwide prevalence of hidradenitis suppurativa (HS) is around 0.4%. If that seems like an insignificant global total, let’s translate that into a solid number: 31,200,000 persons suffer from this chronic inflammatory skin disease characterized by occlusion of hair follicles as a primary pathogenic factor.

It’s a number that says HS may not be as rare as some previously thought. Furthermore, the study researchers wrote in their May 26, 2021, JAMA Dermatology article,1 “Findings from this study may help in the formulation of policies and guiding principles for better disease diagnosis and management.”

In addition, explained study lead author Abdulhadi Jfri, MD, MSc, of the division of dermatology at McGill University Health Centre, Montreal General Hospital, and colleagues, an increasing number of studies continue to demonstrate that “several critical needs of HS are unmet due to a lack of disease awareness, a delay in diagnosis, a poor control of symptoms, and high frequency of comorbidities.” In addition, the researchers wrote, “There are scarce data regarding the prevalence of HS.”

Exactly how important is this link between disease prevalence and better disease diagnosis and management? Prevalence reflects the burden of a disease in a certain population, which can include monetary costs, life expectancy, morbidity, quality of life, and other indicators. Equally as important, knowledge of disease burden can help guide decision makers to determine where investments in healthcare should go – which can have an enormous impact of better disease diagnosis and management.2

Collecting Data

Following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline, this study included PubMed, Cochrane registry,, and evidence by NHS UK and Trip databases to estimate global HS prevalence. Only cross-sectional studies or baseline assessments of longitudinal cohorts using census-based surveys or probabilistic and non-probabilistic epidemiologic methods were considered. Search terms included prevalence OR incidence OR epidemiology AND  hidradenitis suppurativa OR acne inversa OR Verneuil’s disease. No language restriction was applied. The 16 studies eventually selected for quantitative assessment represented 38,082,054 participants along with prevalence estimates from Western European and Scandinavian countries, the US, and Australia.

Meta-analysis with random effects, after adjusting for publication bias in the prevalence estimates, revealed a 0.40% prevalence for HS. Studies based on clinical samples revealed a higher pooled prevalence of HS (1.7%) than population-based studies (0.3%). The researchers also noted that the study’s estimated prevalence of HS includes wide variations, with a point prevalence ranging from 0.3% in Germany to 4.1% in Denmark due to heterogeneous measurement methods and populations being studied.

Expanding on this significant geographical HS variance, the study researchers concluded that this variation may be due to different ethnicity concentrations on different continents. “Particularly, Asian populations were associated with lower prevalence compared to their European counterparts. Additionally, a higher relative prevalence of HS was found in Asian males compared to European and American males. These findings have implications in understanding the epidemiology and management of HS.”

1. Jfri A, Nassim D, O’Brien E, Gulliver W, Nikolakis G, Zouboulis CC. Prevalence of Hidradenitis Suppurativa: A Systematic Review and Meta-regression Analysis. JAMA Dermatol.Published online May 26, 2021. doi:10.1001/jamadermatol.2021.1677. Available from Accessed on June 11, 2021.

2. Noordzij M, Dekker FW, Zoccali C, Jager KJ. Measures of disease frequency: prevalence and incidence. Nephron Clin Pract. 2010;115(1):c17-20. doi: 10.1159/000286345. Epub 2010 Feb 19. PMID: 20173345. Available from Accessed on June 12, 2021.