Anemia in Patients with Hidradenitis Suppurativa: Prevalence and Risk Factors in a Hospital-Based Cohort.

We examined the prevalence and risk factors of anemia in patients with hidradenitis suppurativa (HS). The presence of anemia and information on risk factors was obtained through interview, clinical examination, and blood samples in a cohort of 367 consecutive patients with HS. The overall prevalence of anemia was 9.3% (11.4% in men and 8.1% in women). Altogether 7.9%, 7.0%, and 20.4% of patients with Hurley stage I, II, and III were anemic, respectively. Risk factors for anemia included increasing age, nonwhite ethnicity, sporadic (nonfamilial) HS, concomitant inflammatory bowel disease (IBD), absence of hypertension, and absence of infected lesions in the preceding month. We found significant inverse correlations between hemoglobin level and inflammatory markers in the blood. There were significant correlations between hemoglobin and lipid levels, and between lipid levels and inflammatory markers. Hemoglobin levels are lower in patients with more severe HS and with more chronic inflammatory burden compared to those with less disease severity. Older age, nonwhite ethnicity, sporadic (nonfamilial) HS, and IBD are the risk factors of anemia.