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The length of hospital stay in COVID-19 patients using pre-hospital metformin at a Saudi tertiary hospital: a retrospective cohort study

Felemban RA, Mayet TS, Khaimi ZO, Aljabri YH, Hadi MA, Alsulami AF, Althubaiti A, Babaer D

BMC infectious diseases, 2026

Abstract

BACKGROUND: Type 2 diabetes mellitus (T2DM) is prevalent in Saudi Arabia and is associated with severe outcomes from Coronavirus Disease 2019 (COVID-19). Metformin, the most prescribed medication for T2DM, has shown potential antiviral and anti-inflammatory properties that may be relevant in patients with COVID-19. This study evaluated the association of pre-hospital metformin use with length of hospital stay and secondary outcomes among patients with COVID-19 and T2DM.

METHODS: This retrospective cohort study was conducted at King Abdulaziz Medical City in Jeddah from 2020 to 2023 and included hospitalized adult patients with confirmed COVID-19 and pre-existing T2DM. Pre-hospital metformin use was defined as documented within 90 days before hospital admission. Clinical characteristics, treatments, and hospital outcomes were analyzed using electronic health record data.

RESULTS: Metformin use was associated with a significantly shorter hospital stay, with a median time to discharge of five days (95% CI: 4-6) compared with 14 days (95% CI: 7-44) in the non-metformin group. Metformin use was associated with a higher hazard of discharge than nonuse (HR = 1.85, 95% CI: 1.14-3.0; p = 0.012). No statistically significant differences were observed between the two groups for secondary outcomes, including mechanical ventilation, intensive care unit admission, and respiratory complications, defined as acute respiratory distress syndrome and severe respiratory failure.

CONCLUSION:…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

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