Tofacitinib and Baricitinib in Type 2 Diabetic Patients with Rheumatoid Arthritis.

: Recently, a randomized controlled trial suggested a potential benefit of baricitinib in patients with diabetes mellitus, preserving β-cell function. However, the clinical evidence currently available is limited. We aimed to assess the potential impact of tofacitinib and baricitinib on type 2 diabetes mellitus (T2DM) patients with rheumatoid arthritis. : The candidates for this observational, retrospective, single-center study were selected from a cohort of 120 rheumatoid arthritis patients treated with tofacitinib or baricitinib between September 2017 and September 2023. The eligibility criteria included patients with T2DM who were receiving oral antidiabetic drugs (OADs). The primary outcome was the glycosylated hemoglobin (HbA1c) value after 6 months of a JAK inhibitor treatment. Secondary outcomes included body mass index (BMI) and rheumatoid arthritis disease activity. Differences were evaluated using Fisher's exact test, as well as the Mann-Whitney test or the Wilcoxon test. : Thirteen patients were included; 46.2% (6/13) underwent treatment with tofacitinib, while 53.8% (7/13) were treated with baricitinib. At 6 months, baricitinib treatment resulted in a reduction in HbA1c ( = 0.035), with 57.1% (4/7) of patients achieving values <7%, and 28.6% (2/7) of patients requiring a reduction in OAD dosage. Concerning BMI, an increase ( = 0.022) was observed at 6 months following baricitinib administration. All the patients treated with either tofacitinib or baricitinib achieved remission or low disease activity, without requiring statistically significant changes in concomitant rheumatoid arthritis treatment. : In T2DM patients with rheumatoid arthritis, baricitinib can improve insulin sensitivity and glucose uptake, enabling the optimization of T2DM management.