Table 2.

Associations between vitamin C use and death or clinical improvement in the crude analysis and propensity-score analyses

Analysis	Outcomes
	Death	Clinical improvement
No. of events/no. of patients at risk (%)
Vitamin C	12/70 (17.1)	52/70 (74.3)
No vitamin C	7/327 (2.1)	311/327 (95.1)
Crude analysis – hazard ratio (95% CI)	8.64 (3.40–21.94)	0.72 (0.53–0.96)
Propensity-score analyses – hazard ratio (95% CI)
With inverse probability weightinga	2.69 (0.91–7.89)	0.76 (0.55–1.07)
With matchingb	2.57 (0.39–16.79)	0.74 (0.48–1.14)

^aThe main analysis with a hazard ratio by a Cox regression model adjusted by basic stabilized inverse probability treatment weighting.

^bThe hazard ratio from a paired Cox regression.