The road to biologics in patients with hidradenitis suppurativa: a nationwide drug utilization study.

Background: Prolonged systemic antibiotic treatment is often a part of management of hidradenitis suppurativa (HS). Although biologic therapies are now available, the patient's treatment journey leading to biologic therapy is unclear.

Objectives: To examine treatment patterns and duration of systemic treatment use in patients with HS preceding biologic therapy.

Methods: We identified all patients with HS receiving treatment with biologics in the Danish National Patient Registry from 2010 to 2018 and extracted their entire prescription history of specific systemic treatments from the Danish National Prescription Registry since its inception in 1995. The patients' treatment journeys are graphically displayed through Sankey diagrams and box plots generated to show temporal distributions. Descriptive patient characteristics were presented as frequencies with percentages for categorical variables and as means with SDs or medians with interquartile ranges (IQRs) for continuous variables.

Results: A total of 225 patients with HS were included. Patients had most frequently been treated with penicillin (n = 214; 95·1%), dicloxacillin (n = 194; 86·2%), tetracycline (n = 145; 64·4%) and rifampicin/clindamycin (n = 111; 49·3%), as well as the retinoids isotretinoin and acitretin, and dapsone. Prior to biologic therapy, patients received a mean of 4·0 (SD 1·3) different systemic therapies, across a mean of 16·9 (SD 11·3) different treatment series. The mean time from first systemic therapy until biologic therapy was initiated was 15·3 (SD 5·1) years [8·2 (SD 5·9) years when excluding penicillin and dicloxacillin].

Conclusions: Patients with HS who receive biologic therapy have long preceding treatment histories with multiple drug classes and treatment series, many of which are supported by relatively weak evidence in HS. Delay in the initiation of biologic therapy may represent a missed opportunity to prevent disease progression. What is already known about this topic? The treatment journey leading to biologic therapy in patients with HS has not previously been investigated. What does this study add? Our data from 225 patients with HS illustrate that patients who receive biologic therapy have long preceding treatment histories with multiple drug classes and treatment series, many of which are supported by relatively weak evidence in HS.