Table 4.

Hazard Ratios for Mortality and Second Outcomes between Individuals in the Metformin and the Non-metformin Groups

Metformin versus Non-metformin	Time-Varying Cox Model Exposure before PSM		Hazard in All Groups after PSM
	Adjusted HRa (95% CI)	p Valueb	Adjusted HRc (95% CI)	p Valued
Mortality	0.87 (0.36,2.12)	0.757	1.65 (0.71,3.86)	0.247
ARDS	0.66 (0.46,0.96)	0.028	0.85 (0.61,1.17)	0.317
DIC	0.44 (0.05,4.00)	0.467	1.68 (0.26,10.90)	0.586
Heart failure	0.61 (0.43,0.87)	0.006	0.59 (0.41,0.83)	0.003
Acute kidney injury	0.71 (0.18,2.79)	0.627	0.65 (0.19,2.24)	0.491
Acute heart injury	1.14 (0.73,1.79)	0.559	1.02 (0.62,1.66)	0.947

HR, hazard ratio; CI, confidence interval; ARDS, acute respiratory distress syndrome; DIC, disseminated intravascular coagulation.

^aIn the time-varying Cox model, adjusted variables for comparison between the metformin and the non-metformin cohorts included age, gender, comorbidities (cerebrovascular disease and coronary heart disease), blood glucose, C-reactive protein, estimated glomerular filtration rate, alanine aminotransferase, and creatinine.

^bThe p values were calculated based on time-varying Cox model.

^cIn the mixed-effect Cox proportional hazard model, adjusted variables for comparison between the metformin and the non-metformin cohorts included age, gender, C-reactive protein, aspartate aminotransferase, urea, red blood cell, creatinine, and hospital site as a random effect.

^dThe p values were calculated based on mixed-effect Cox proportional hazard model.