Anemia and systemic inflammatory markers in patients with perianal disease- hidradenitis suppurativa and inflammatory bowel disease

Background: Hidradenitis suppurativa (HS) and inflammatory bowel disease (IBD) have been reported to have a wide variety of overlaps in their pathogenesis, laboratory findings, and histopathology. These two diseases can form draining tunnels and are difficult to differentiate, particularly from fistulizing lesions in the perianal area. Objective: This retrospective study of HS and IBD patients with perianal lesions sought to analyze the anemia and systemic inflammation biomarkers in these disease groups.Methods: A retrospective chart review was conducted on the laboratory findings of total 212 patients with perianal disease - 72 with HS, 78 with IBD, and 62 with both HS and IBD - who were evaluated at Mayo Clinic between 1998 and 2021.Results: In the HS group, 45.8% of males and females were anemic, compared to 58.1% of males and 73.5% of females in the IBD group. The HS + IBD group had the highest prevalence of anemia and the lowest hemoglobin levels. The odds ratio for being anemic was 2.19 for the IBD group and 4.05 for the IBD + HS group compared to the HS group. Monocyte/lymphocyte ratio (MLR) and platelet/lymphocyte ratio (PLR) were significantly higher in the IBD group, whereas neutrophil/lymphocyte ratio (NLR) was significantly higher in the IBD + HS group.Conclusion: Our data show for the first time the prevalence of anemia in patients with HS and IBD who have perianal lesions. In addition, noninvasive biomarkers using complete blood counts such as MLR, PLR, and NLR could be useful not only in differentiating perianal HS from fistulizing perianal IBD, but also in selecting treatment.