Representation of older adults in randomized controlled trials on systemic treatment in plaque psoriasis: A systematic review

Background: Psoriasis is frequently seen in older patients, and systemic treatment is often indicated. Randomized controlled trials (RCTs) generally maintain strict inclusion and exclusion criteria, which might lead to a disproportionally high exclusion rate of older adults. Objective: To determine the representation of older adults (>= 65 years) in RCTs studying systemic treatment in plaque psoriasis. Methods: A systematic literature search was performed in PubMed/MEDLINE, Embase, and CENTRAL, including RCTs concerning systemic treatments in plaque psoriasis in the past 15 years. Direct exclusion (based on age limits) and indirect exclusion (other exclusion criteria) were assessed. Study selection and data extraction were performed by 2 independent reviewers. Results: Of 162 trials reviewed in full, 54 (33.3%) maintained an upper age limit (55-85 years). Of the remaining 108 trials, 106 reported exclusion criteria and did not use an upper age limit. However, 96 (90.6%) of these trials used exclusion criteria that might unequally affect older adults. The exclusion criteria serious concurrent infection (n = 104, 66.7%) and malignancy (n = 100, 64.1%) were most commonly mentioned in the included RCTs. Limitations: Only published RCTs were included. Conclusion: Older adults might be poorly represented in RCTs studying systemic treatment in plaque psoriasis because of a high rate of direct and indirect exclusion.