Primary outcome
Seven trials (7, 13-15, 18, 29) that reported intubation rates indicated that NHFOV reduced the intubation rate significantly, compared with NIPPV (Fig. 2). However, the subgroup analysis by study type found no significant differences in the rates between NHFOV and NIPPV in the cohort studies or RCTs (Fig. 2).
Three trials (8, 26,36) did not limit the time of reintubation, and indicated that NHFOV reduced the reintubation rate significantly, compared with NIPPV (Fig. 3a). However, the subgroup analysis by study type found no significant differences in the rates between NHFOV and NIPPV in the cohort studies or RCTs (Fig. 3a). Five RCTs (8, 9, 17, 20, 28) reported reintubation rates within 72 h. No significant difference was found in the reduction of the reintubation rate between NHFOV and NIPPV (Fig. 3b). Four trials (16, 19, 21, 22) that reported reintubation rates within 7 days found no significant differences between NHFOV and NIPPV(suppl. eFig. 3). Stratification of the results by study design showed the pooled random effects OR was 0.70 for RCTs and 0.72 for cohort studies (suppl. eFig. 3).