The objective of this 9-year long study was to evaluate the rate of QuantiFERON TB Gold test (QFT) conversion in psoriasis patients during biologics over time. Tuberculosis (TB) screening is mandatory for psoriasis biologic treatment. However, pieces of evidence regarding TB screening results during biological treatment are conflicting. The researchers and high-level doctors performed a 9‐year single-center retrospective study to evaluate QFT conversion rates in patients affected by moderate‐to‐severe plaque psoriasis under available biological therapies (anti‐TNF‐α, IL‐12/23, IL‐17). For each patient, demographic data, age, gender, comorbidities, previous psoriasis therapy, and ongoing treatment type were registered. Five‐hundred twenty‐six patients (61.2% male, with a mean age of 52.6 ± 13.9 years) treated with biologics were enrolled.

The study revealed that QFT conversion occurred in 6.5% of patients over a mean treatment duration of 3.2 years. On average, QFT conversion occurred after 34.05 months of treatment. Anti‐TNF‐α drugs, and among them, adalimumab above all (35.5% of all cases), were the most commonly involved treatment during QFT conversion, followed by anti‐IL‐12/23 and anti‐IL‐17. However, differences among biologics classes or single biologics did not approach statistical significance.