Gender differences in biologic treatment outcomes-a study of 1750 patients with psoriatic arthritis using Danish Health Care Registers.

Objective: We aimed to investigate gender differences in disease manifestations, patient-reported outcomes, comorbidities and treatment effectiveness among patients with PsA treated with their first TNFα inhibitor (TNFI).

Methods: In this observational cohort study, the DANBIO register provided prospectively collected data on PsA patients who initiated their first TNFI in 2000-15. Comorbidity information was achieved from the Danish Nationwide Patient Register. Response to treatment was assessed according to EULAR and ACR criteria at 3 and 6 months. Cox and logistic regression models analysed the impact of gender on TNFI persistence and response, respectively, while adjusting for a priori selected confounders including clinical-, laboratory- and patient-reported factors, comorbidities and lifestyle characteristics.

Results: A total of 1750 PsA patients (935 women) were included. At baseline, women were older (49 years/47 years), more often smokers (32%/26%), had worse patient-reported scores (e.g. global score 71 mm/65 mm) and higher frequencies of hospital-diagnosed anxiety or depression (7%/4%) and chronic pulmonary disease (7%/3%) than men (all P < 0.01). Median TNFI persistence was 3.8 years (95% CI: 3.0, 5.7) in men vs 1.4 (1.1, 1.8) in women (P < 0.001). Men had higher odds of achieving response after 3 and 6 months, for example, adjusted odds ratio = 3.2 (1.6, 6.1) for EULAR good/moderate response (vs women) at 6 months.

Conclusion: Male gender was strongly associated with greater TNFI treatment effectiveness. Adjustment for baseline risk factors including patient-reported outcomes, disease activity, comorbidities and lifestyle factors did not influence this relationship, which suggests a role of biological factors.