Incidence Rates of Psoriasis in Children With Inflammatory Bowel Disease and Juvenile Arthritis Treated With Tumor Necrosis Factor Inhibitors and Disease-Modifying Antirheumatic Drugs

Objective To estimate the differential effect of tumor necrosis factor inhibitor (TNFi) therapies and presence or absence of conventional synthetic disease-modifying antirheumatic drugs (DMARDs) on the incidence of psoriasis (PsO) in children with inflammatory bowel disease (IBD), juvenile idiopathic arthritis (JIA), and chronic nonbacterial osteomyelitis (CNO). Methods This was a retrospective cohort study from 2008 to 2020. TNFi and DMARD exposures were dichotomized as ever/never. The primary outcome was incident PsO. Incidence rates (IRs) of PsO were stratified by underlying diagnosis, TNFi agent, and DMARD use. Poisson regression was used to assess the IR ratios (IRRs) between exposure groups. Results There were 5088 children who met the inclusion criteria: 3794 (75%) had IBD, 1189 (23%) had JIA, and 105 (2%) had CNO. Of the 2023 children with TNFi exposure, 613 (30%) and 1410 (70%) were with or without a DMARD, respectively. When controlling for DMARD, sex, and family history of PsO, the IRR of developing PsO in patients exposed to adalimumab (ADA) was 2.70 times higher (95% CI 1.53-4.75; P < 0.001) than those who did not receive any TNFi treatment. IRR was lower, but not significantly different, for patients exposed to infliximab (IFX; IRR 2.34, 95% CI 1.56-3.51; P < 0.001) and etanercept (ETN; IRR 2.21; 95% CI 1.17-4.21; P = 0.006) compared to TNFi-unexposed patients. IRR of TNFi exposure was lower by 0.25 (P < 0.001) in DMARD-exposed patients compared to non–DMARD-exposed patients. Conclusion IRR of TNFi-induced PsO was not significantly different among ADA, IFX, and ETN. However, for patients with exposure to any of the TNFi evaluated, the IRR was significantly lower in those also exposed to a DMARD.