Fig. 6

Effect of oral and intravenous vitamin C on POAF and on hospital stay. The open square indicates the pooled effect of oral vitamin C in the non-US trials and the filled in square indicates the pooled effect of intravenous vitamin C trials in the non-US trials. The open circle indicates the pooled effect of oral vitamin C in the US trials. The estimates are from Figs. 2, 3 and 4. The horizontal and vertical lines indicate the 95% CI ranges for each effect. The Rebrova (2012) [24] and Samadikhah (2014) [25] trials contribute to the estimate of oral vitamin C effect on POAF occurrence in the non-US trials, but they did not report the findings on hospital stay