Early intubation and clinical outcomes in patients with severe COVID-19: a systematic review and meta-analysis

Background Evidence regarding the timing of the application of mechanical ventilation among patients with severe coronavirus disease (COVID-19) is insufficient. This systematic review and meta-analysis aimed to evaluate the effectiveness of early intubation compared to late intubation in patients with severe and critical COVID-19. Methods For this study, we searched the MEDLINE, EMBASE, and Cochrane databases as well as one Korean domestic database on July 15, 2021. We updated the search monthly from September 10, 2021 to February 10, 2022. Studies that compared early intubation with late intubation in patients with severe COVID-19 were eligible for inclusion. Relative risk (RR) and mean difference (MD) were calculated as measures of effect using the random-effects model for the pooled estimates of in-hospital mortality, intensive care unit (ICU) length of stay (LOS), duration of mechanical ventilation (MV), hospital LOS, ICU-free days, and ventilator-free days. Subgroup analysis was performed based on the definition of early intubation and the index time. To assess the risk of bias in the included studies, we used the Risk of Bias Assessment tool for Non-randomized studies 2.0. Results Of the 1523 records identified, 12 cohort studies, involving 2843 patients with severe COVID-19 were eligible. There were no differences in in-hospital mortality (8 studies, n = 795; RR 0.91, 95% CI 0.75-1.10, P = 0.32, I-2 = 33%), LOS in the ICU (9 studies, n = 978; MD -1.77 days, 95% CI -4.61 to 1.07 days, P = 0.22, I-2 = 78%), MV duration (9 studies, n = 1,066; MD -0.03 day, 95% CI -1.79 to 1.72 days, P = 0.97, I-2 = 49%), ICU-free days (1 study, n = 32; 0 day vs. 0 day; P = 0.39), and ventilator-free days (4 studies, n = 344; MD 0.94 day, 95% CI -4.56 to 6.43 days, P = 0.74, I-2 = 54%) between the early and late intubation groups. However, the early intubation group had significant advantage in terms of hospital LOS (6 studies, n = 738; MD -4.32 days, 95% CI -7.20 to -1.44 days, P = 0.003, I-2 = 45%). Conclusion This study showed no significant difference in both primary and secondary outcomes between the early intubation and late intubation groups. Trial registration This study was registered in the Prospective Register of Systematic Reviews on 16 February, 2022 (registration number CRD42022311122).