Effect of dipeptidyl peptidase-4 inhibitors on tumor necrosis factor alpha levels in patients with type 2 diabetes mellitus.

Aims: Dipeptidyl peptidase-4 inhibitors (DPP-4i) served as oral antidiabetic agents for treatment of type 2 diabetes mellitus (T2DM). Although an action on glucose homeostasis was identified, no well-rounded illustration had been established on the changes of tumor necrosis factor alpha (TNF-alpha) levels during DPP-4i treatment. This study aimed to explore the anti-inflammatory effect of DPP-4i on TNF-alpha in patients with T2DM.
Methods: PubMed, Embase and Cochrane Library were systematically searched from inception to May 31, 2024. Randomized controlled trials exploring the impact of DPP-4i on TNF-alpha levels were identified. Risk of bias was assessed according to the Cochrane criteria. A fixed or random-effects model was selected to pool estimate on whether the heterogeneity was present. Subgroup analysis were performed to explore the potential factors that influenced heterogeneity. Related meta-analysis was conducted with the software of Revman 5.3 and STATA 12.0.
Results: Eleven trials involving 884 participants with T2DM were included. Pooled estimates suggested that DPP-4i did not significantly modulate TNF-alpha levels (WMD, - 0.70, 95% CI - 1.94 to 0.53, P = 0.26) in T2DM. DPP-4i produced a significant effect on TNF-alpha (WMD, - 4.50 pg/mL, 95% CI - 4.68 to - 4.32, P < 0.00001) when compared to placebo, and a comparable effect was demonstrated on TNF-alpha (WMD, 0.10 pg/mL, 95% CI - 0.11 to 0.30, P = 0.35) in comparison with active agents. Estimate was stable according to the sensitivity test. Subgroup analysis revealed that heterogeneity might not correlate with baseline glycated hemoglobin (HbA1c), age or treatment duration.
Conclusions: A significant effect of DPP-4i on TNF-alpha levels was present in T2DM when compared to placebo. Administration of DPP-4i produced no significant effect on TNF-alpha in comparison with active comparators. Further studies with large samples should be performed to illustrate the impact of DPP-4i on TNF-alpha levels in T2DM. Trial registration International Prospective Register for Systematic Review (PROSPERO) number: CRD42020185479.
(© 2024. The Author(s).)