Impact of Body Mass Index on the Efficacy of Biological Therapies in Patients with Psoriasis: A Real-World Study

Background: The efficacy of biological therapies used for the treatment of chronic plaque psoriasis can be influenced by numerous variables including body mass index (BMI). Objective: This study aimed to evaluate the impact of BMI on the short-term and long-term efficacy of biological therapies in clinical practice and to identify the best therapeutic options in obese patients (BMI ≥ 30 kg/m2). Methods: A multicentric retrospective study was conducted in patients who initiated a biological therapy during the period January 2006–December 2019. The proportion of patients achieving a 90% improvement of baseline Psoriasis Area and Severity Index at weeks 12 and 24 was calculated also recording the 12- and 24-month drug survival as a measure of long-term efficacy, performing multivariate analyses to assess the impact of different variables. Results: Five hundred and four patients with psoriasis were included. After 12 and 24 weeks, the proportion of patients achieving a 90% improvement of baseline Psoriasis Area and Severity Index response was higher in patients with a BMI < 30 kg/m2 compared with those with a BMI ≥ 30 kg/m2 [54.90% vs 43.45% (p = 0.014) at week 12 and 66.84% vs 56.55% (p = 0.021) at week 24]. The Kaplan–Meier survival curves showed how obese patients had a higher probability of discontinuation due to a lack or loss of efficacy (p = 0.0192) compared with non-obese patients. The drug survival analysis also showed that BMI negatively affected the drug survival of secukinumab (odds ratio 1.27, p < 0.001) and ustekinumab (odds ratio 1.06, p = 0.050), while the long-term efficacy of adalimumab, etanercept, and ixekizumab was not influenced by BMI. Conclusions: Obesity (BMI ≥ 30 kg/m2) negatively affects the clinical response of biological drugs in psoriatic patients, with anti-interleukin drugs being more affected by BMI than anti-tumor necrosis factor drugs.