Table 4. Primary and Secondary Outcomes in the High-Flow Nasal Oxygen Group vs the Conventional Oxygen Therapy Group.
| High-flow nasal oxygen | Conventional oxygen therapy | Difference (95% CI)a | Unadjusted | Adjusted | |||
|---|---|---|---|---|---|---|---|
| Effect estimate (95% CI) | P valueb | Effect estimate (95% CI)c | P valueb | ||||
| Primary composite outcome | |||||||
| Tracheal intubation or mortality within 30 d, No./total (%) | 184/415 (44.3) | 166/368 (45.1) | AD, −1 (−8 to 6) | OR, 0.97 (0.73 to 1.29) | .83 | OR, 0.94 (0.68 to 1.29) | .69 |
| Secondary outcomes | |||||||
| Individual components of the primary composite outcome, No./total (%) | |||||||
| Tracheal intubation within 30 d | 170/415 (41.0) | 153/368 (41.6) | AD, −1 (−8 to 6) | OR, 0.98 (0.73 to 1.30) | .86 | OR, 0.94 (0.69 to 1.30) | .72 |
| Mortality within 30 d | 78/416 (18.8) | 74/370 (20.0) | AD, −1 (−7 to 4) | OR, 0.92 (0.65 to 1.32) | .66 | OR, 0.97 (0.65 to 1.46) | .90 |
| Tracheal intubation rate, No./total (%)d | 169/415 (40.7) | 154/368 (41.8) | AD, −1 (−8 to 6) | OR, 0.95 (0.72 to 1.27) | .75 | OR, 0.92 (0.67 to 1.27) | .62 |
| Admission to intensive care unit, No./total (%) | 252/408 (61.8) | 214/361 (59.3) | AD, 2 (−4 to 9) | OR, 1.11 (0.83 to 1.48) | .48 | OR, 1.04 (0.75 to 1.45) | .81 |
| Duration of invasive mechanical ventilation after tracheal intubation, median (IQR), de | (n = 169) 15.0 (8.0 to 26.0) |
(n = 154) 12.0 (6.0 to 23.0) |
MDND, 3.0 (−1.0 to 7.0) | HR, 0.92 (0.71 to 1.20) | .56 | HR, 1.01 (0.76 to 1.34) | .96 |
| Time to event, median (IQR), d | |||||||
| Tracheal intubationf | (n = 169) 1.0 (0 to 3.0) |
(n = 154) 1.0 (0 to 3.0) |
MDND, 0 (−0.4 to 0.4) | HR, 0.98 (0.78 to 1.21) | .82 | HR, 0.92 (0.74 to 1.16) | .49 |
| Deathg | (n = 88) 16.5 (9.0 to 22.5) |
(n = 85) 17.0 (11.0 to 24.0) |
MDND, 0 (−3.4 to 3.4) | HR, 0.94 (0.68 to 1.29) | .69 | HR, 0.94 (0.67 to 1.32) | .74 |
| Mortality, No./total (%) | |||||||
| During intensive care unit stay | 72/251 (28.7) | 65/214 (30.4) | AD, −2 (−10 to 7) | OR, 0.92 (0.62 to 1.38) | .69 | OR, 0.98 (0.63 to 1.54) | .94 |
| During hospital stay | 86/405 (21.2) | 80/359 (22.3) | AD, −1 (−7 to 5) | OR, 0.94 (0.67 to 1.33) | .73 | OR, 0.99 (0.67 to 1.47) | .97 |
| Length of stay, mean (SD), d | |||||||
| Intensive care unith | (n = 407) 10.5 (15.6) |
(n = 361) 9.6 (14.1) |
MD, 0.95 (−1.16 to 3.07) | .38 | MD, 0.47 (−1.57 to 2.50) | .65 | |
| Hospitali | (n = 405) 18.3 (20.0) |
(n = 359) 17.1 (18.0) |
MD, 1.21 (−1.50 to 3.93) | .38 | MD, 0.33 (−2.28 to 2.94) | .80 | |
Abbreviations: AD, absolute difference; HR, hazard ratio; MD, mean difference; MDND, median difference; OR, odds ratio.
Expressed as a percentage unless otherwise indicated.
The cutoff values for the P values to define statistical significance for the primary comparison of high-flow nasal oxygen vs conventional oxygen therapy corrected for the interim analyses were equivalent to .044 for 2-sided P values (calculated using the method described by Jennison and Turnbull22). For the secondary outcomes (not corrected for the interim analyses), the significance threshold of .05 was used.
Adjusted for age, sex, morbid obesity (defined as a body mass index >35), ethnicity, Fio2, respiratory rate, and treatment phases. Hospital site was included as a random effect.
Outcome included tracheal intubation during the index hospital admission.
The proportional hazards assumption was tested in the unadjusted model; the P value was .32.
The proportional hazards assumption was tested in the unadjusted model; the P value was .81.
The proportional hazards assumption was tested in the unadjusted model; the P value was .64.
Patients who were not admitted to intensive care unit were allocated a stay of 0 days.
Included time from emergency department arrival to hospital discharge.