Dipeptidyl peptidase-4 inhibitor use and mortality in COVID-19 patients with diabetes mellitus: an updated systematic review and meta-analysis

Background: Few observational studies have shown a beneficial effect of dipeptidyl peptidase-4 inhibitors (DPP4i) in patients with coronavirus disease 2019 (COVID-19), although results are not consistent The present systematic review and meta-analysis was undertaken to provide a precise summary of the effect of DPP4i use (preadmission or in-hospital) and mortality in COVID-19 patients with diabetes mellitus (DM) Methods: PubMed and Google Scholar databases were systematically searched using appropriate keywords to 4 January 2021, to identify observational studies reporting mortality in COVID-19 patients with DM using DPP4i versus those not using DPP4i Preadmission and in-hospital use of DPP4i were considered Study quality was assessed using the Newcastle–Ottawa Scale Unadjusted and adjusted pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated Subgroup analysis was performed for studies reporting preadmission and in-hospital use of DPP4i Results: We identified nine observational studies of high quality pooling data retrieved from 7008 COVID-19 patients with DM The pooled analysis of unadjusted and adjusted data did not show any significant association between DPP4i use and mortality in COVID-19 patients with DM However, on subgroup analysis, we found that in-hospital (and not preadmission) DPP4i use was associated with reduced mortality (unadjusted OR 0 37, 95% CI 0 23, 0 58, p < 0 0001, I2 = 0% and adjusted OR 0 27, 95% CI 0 13, 0 55, p = 0 0003, I2 = 12%) Conclusions: In-hospital use of DPP4i is associated with a significant reduction in COVID-19 mortality Hence, it would be prudent to initiate or continue DPP4i in COVID-19 patients with DM if not contraindicated