Infection Risk Higher in HS Compared With Psoriasis With Adalimumab

Adults with hidradenitis suppurativa (HS) treated with adalimumab face a significantly higher risk of serious infections compared with those with psoriasis, according to a new cohort study.¹ The findings highlight the need for tailored infection-prevention strategies for the HS population, including closer monitoring for sepsis and genitourinary infections.

This retrospective cohort study is published in JAMA Dermatology.

A large cohort study finds elevated risks of sepsis, genitourinary infections, and longer hospital stays in patients with hidradenitis suppurativa (HS). | Image credit: luchschenF - stock.adobe.com

“Our study found that among adalimumab users, patients with HS had a 53% higher risk of hospitalization from NCI [noncutaneous infection] compared with patients with psoriasis,” wrote the researchers of the study. “Our analytical framework was designed to adjust for the immunomodulatory impact of standard therapies and the potential contribution of disease severity to infection risk. The findings thereby suggest an increased, inherently higher baseline risk of severe infections in the HS population.”

Adalimumab, marketed as Humira by AbbVie, is a recombinant human immunoglobulin G1 monoclonal antibody that targets tumor necrosis factor.² First approved by the FDA in 2002, it is available as an injection and is widely used to treat a range of autoimmune and inflammatory conditions, including rheumatoid arthritis, psoriatic arthritis, plaque psoriasis, Crohn’s disease, ulcerative colitis, juvenile idiopathic arthritis, uveitis, ankylosing spondylitis, and HS.

The study used deidentified claims data from the MarketScan database to evaluate infection risk among adults with HS and psoriasis who initiated adalimumab therapy between January 2017 and December 2020.¹ Patients were identified using International Classification of Disease, Tenth Revision (ICD-10) diagnostic codes and prescription records. The primary outcome of hospitalization due to noncutaneous infections was analyzed and adjusted for confounders. Secondary outcomes included infection type and hospital length of stay (LOS). Data analysis was conducted between October 2023 and March 2024.

Among 10,349 new adalimumab users included in the study, 1650 had HS and 8699 had psoriasis. Patients with HS were younger (mean [SD] age 36.2 [11.5] vs. 46.5 [12.4] years) and more likely to be female (77.0% vs. 50.2%) compared with those with psoriasis, and they had higher rates of comorbidities such as obesity, Crohn disease, anxiety, and depression.

After adjustment, the HS cohort had a 53% higher risk of hospitalization for serious infection (HR, 1.53; 95% CI, 1.34-1.86). They also had a greater likelihood of developing sepsis (incident rate ratio [IRR], 2.07; 95% CI, 1.35-3.12) and genitourinary infections (IRR, 2.22; 95% CI, 1.22-3.86) compared with patients with psoriasis. In addition, hospital stays were more prolonged in the HS group, with 28% higher odds of extended LOS (OR, 1.28; 95% CI, 1.13-1.45).

However, the researchers noted some limitations. Despite its large, nationally representative cohort, the study did not account for adalimumab dose-response or adjust for steroid and chronic antibiotic use. Additionally, the HS identification algorithm, based on a single ICD-10 code with prescription data, lacked formal validation and risked misclassification.

Despite these limitations, the researchers believe the study identified a greater risk of infection in patients with HS treated with adalimumab compared with patients with psoriasis treated with adalimumab.

“The nature of infections also varied, with patients with HS more frequently experiencing sepsis and genitourinary tract infections,” wrote the researchers. “Therefore, these findings underscore the need for strategies to reduce the infection risk in this population. Future studies will be important to further understand the risk of infection in this population, focusing on the contribution of the disease severity and therapeutic regimens, as well as investigating prophylactic strategies to reduce infection burden in the HS population.”

References

1. Wafae BGDO, Charrow AP, Stein D, et al. Risk of serious infection with adalimumab in hidradenitis suppurativa compared with psoriasis. JAMA Dermatol. Published online August 20, 2025. doi:10.1001/jamadermatol.2025.2881

2. Humira FDA approval history. Drugs.com. Last updated August 25, 2022. Accessed September 2, 2025. https://www.drugs.com/history/humira.html