Win Ratio approach for the composite outcome of postoperative pulmonary complications: Secondary analysis of a harmonised and pooled database of three randomised clinical trials

BACKGROUND The win ratio analysis method might provide new insight on the impact of positive end-expiratory pressure (PEEP) on clinical outcomes. OBJECTIVE The aim is to re-analyse the results of the 'Re-evaluation of the effects of high PEEP with recruitment manoeuvres vs. low PEEP without recruitment manoeuvres during general anaesthesia for surgery' (REPEAT) study using the win ratio analysis. DESIGN Individual patient data meta-analysis. SETTING Three international multicentre randomised trials. PARTICIPANTS Patients undergoing general anaesthesia for surgery. INTERVENTION High vs. low PEEP. MAIN OUTCOME MEASURE Hierarchical composite endpoint of: all-cause hospital mortality; hospital length of stay; need for postoperative mechanical ventilation; severe pulmonary complications; and mild pulmonary complications. RESULTS A total of 3774 patients undergoing general anaesthesia for surgery were included in this analysis. The median (interquartile range [IQR]) age was 57 [45 to 68] years and 2077 (55%) were women. A total of 3 560 720 comparison pairs were produced. The high PEEP group had a higher percentage of losses than wins in hospital mortality (1.1 vs. 0.9%) and hospital length of stay (33.8 vs. 33.2%), comparable percentages of losses and wins in postoperative invasive mechanical ventilation (0.2 vs. 0.2%), a higher percentage of wins in severe complications (2.5 vs. 2.1%) and a higher percentage of ties in mild complications (18.7 vs. 3.9% wins vs. 3.3% losses). The win ratio for high PEEP compared with low PEEP group was 1.00 (95% CI 0.92 to 1.09). CONCLUSION No beneficial effects of high PEEP compared with low PEEP were found in this win ratio analysis.