Risk of tuberculosis infection and serial changes in interferon‐gamma release assays in elderly patients with psoriasis receiving biologic therapy

Elderly patients constitute a significant proportion of patients with psoriasis. Nonetheless, treatment for older patients is more challenging than that for younger ones. Biologic agents are preferable to other systemic drugs for elderly patients with moderate-to-severe psoriasis owing to their high efficacy and favorable tolerability. However, there are limited data on tuberculosis infection risk in elderly patients with psoriasis receiving biologic therapy. This study aimed to evaluate the risk of active tuberculosis and latent tuberculosis infection, assess the serial interferon-gamma release assay results, and evaluate treatment compliance and adverse effects of latent tuberculosis infection treatment in elderly patients with psoriasis on biologic therapy. In this single-center retrospective study, medical charts of elderly patients (age ≥ 65 years) with psoriasis who were treated with a biologic agent (guselkumab, adalimumab, secukinumab, or ustekinumab) between January 2015 and December 2020 were reviewed. We analyzed the results of chest X-rays and those of whole-blood interferon-gamma release assays performed for latent tuberculosis infection screening at baseline (IGRA0) and subsequently at follow-up after initiating biologic therapy (IGRA1). In total, 90 patients underwent IGRA0; 46 (51.11%) of them had latent tuberculosis infection before starting biologic therapy. Overall, four and two patients experienced seroconversion and active tuberculosis during biologic therapy, respectively. The interferon-gamma release assay reversion rate was 29.1%, and the interferon-gamma level significantly decreased in all patients after latent tuberculosis infection treatment (p = 0.004). Latent tuberculosis infection treatment was well tolerated in elderly patients (completion rate, 100%). The risk of latent tuberculosis infection in elderly patients with psoriasis on biologic therapy was comparable to that previously reported for all age groups. However, the active tuberculosis rate was relatively higher.