Purpose: This study aims to investigate risk indicators of in-hospital mortality and severity of coronavirus disease-2019 (COVID-19) in patients with diabetes mellitus (DM).

Methods: In this retrospective study, we studied patients with COVID-19 referred to Sina Hospital, Tehran, Iran, from February 20 to May 14 , 2020 . Patients with either a positive real-time reverse-transcriptase polymerase-chain-reaction test of swab specimens or high clinical suspicion according to the World Health Organization interim guidance were included . We accurately divided all patients into two groups based on diabetes affection and followed-up patients with DM based on incurring death, severe COVID-19, and in-hospital complications .

Results: We enrolled 574 patients with COVID-19 in the final analysis, of whom 176 (30.7 %) patients had DM . In this study , 104 (18.1 %) patients deceased, and 380 (66.2 %) patients incurred severe COVID-19 . We found that COVID-19 patients with DM had a significantly higher mortality rate (P value <0.001), severe disease (P value <0.001), and in-hospital complications (all P values <0.05). Besides that, in patients with DM, admission temperature (odds ratio (OR): 1.69, P value : 0.024), oxygen saturation (OR : 0.92, P value : 0.004), and urea (OR : 1.01, P value : 0.048) were independent risk indicators of in-hospital mortality . In addition, subgroup analysis of diabetic patients based on admission glucose level showed significant differences between these groups regarding acute cardiac injury (P value : 0.044) and acute liver injury (P value : 0.002).

Conclusions: Patients with DM admitted with lower oxygen saturation, elevated temperature, and higher urea are more susceptible to progress to more severe COVID-19 and poor prognosis . This indicates a necessity for more precise care during hospitalization for these patients . Supplementary Information: The online version contains supplementary material available at 10.1007/s40200-020-00701-2.