Polypharmacy and factors associated with polypharmacy in patients with psoriasis

Psoriasis is a chronic inflammatory disease frequently accompanied by multiple comorbidities, which can necessitate the concurrent use of several medications and increase the risk of polypharmacy. Polypharmacy is commonly defined as the regular use of five or more drugs and is associated with adverse outcomes such as side effects, drug–drug interactions, and poor treatment adherence. In this cross-sectional study conducted at the Department of Dermatology and Venereology, Trakya University Faculty of Medicine, between 30 April 2024 and 30 April 2025, we evaluated the prevalence of polypharmacy, factors associated with polypharmacy, and treatment adherence in adults (≥18 years) with clinically and/or histopathologically confirmed chronic plaque psoriasis. A total of 268 patients were included, and the prevalence of polypharmacy was 22.4%. Polypharmacy showed no significant association with sex, educational level, disease duration, or active smoking. In contrast, older age and higher body mass index emerged as important risk factors. Moreover, psoriatic arthritis and cardiovascular, metabolic, and neurological comorbidities were linked to higher polypharmacy rates Treatment adherence was assessed using the Medication Possession Ratio. Dosing frequency was identified as the main determinant of adherence, whereas disease duration, disease severity, comorbidities, and the presence of polypharmacy were not significant predictors. Overall, our findings indicate that age, obesity, and comorbidities drive polypharmacy in psoriasis and that longer dosing intervals are associated with better adherence, supporting the need for individualized, adherence-oriented treatment planning. Keywords: Psoriasis, Polypharmacy, Medication Adherence