The authors regret a single data transcription error at the co-ordinating centre that resulted in numerical errors in several of the reported hazard ratios for all-cause mortality. The correct values (shown in red font) in the text should have been:
Abstract: The summary RR for all-cause mortality was (95% CI , ) across all trials.
Results, All-cause mortality: RRs for all-cause mortality could be obtained for 13 trials, representing 66,447 person-years of follow-up during which deaths were recorded. … The summary RR for all-cause mortality in people randomised to metformin compared with all comparators was (95% CI , ). The summary RR for all-cause mortality was 0.91 (95% CI 0.70, 1.18) in trials comparing metformin to placebo/usual care and (95% CI , ) in trials comparing metformin to active comparators (Fig. 3). The summary RR from 1-year trials was 0.84 (95% CI 0.52, 1.38) and the summary RR from trials longer than 1 year was (95% CI , ). In a post hoc sensitivity analysis, excluding the UKPDS sulfonylurea trial had the effect of reducing the RR for all-cause mortality in metformin compared with placebo/usual care to 0.67 (95% CI 0.49, 0.93; I2 0.0%), and in metformin compared with any comparator to (95% CI , ; I2 0.0%).