Table 1.
Detailed characteristic of the ten enrolled studies.
| Author (year) | Population (H, C) | Age | Country | Study design | NCT | COPD type | Control | Length of therapy | Main outcomesa |
|---|---|---|---|---|---|---|---|---|---|
| Atwood (2017) [17] | 32 (16, 16) | 69 (9) | United States | S, RCT | NCT00990210 | Stable | LTOT | 20 min | (1), (3), (4) |
| Fraser et al. (2016) [18] | 30 (15, 15) | NR | Australia | RCT crossover | ACTRN12613000028707. | Stable | LTOT | 20 min therapy-20 min washout -20 | (1), (3), (4) |
| Guillaume et al. (2019)[19] | 19 (19, 19) | 62.1 (9.1) | French | S, RCT, crossover | NCT03058081 | Stable | Room air or oxygen | 3 days including washout | (1), (4), (7) |
| Helene et al. (2017) [20] | 100 (50, 50) | 67.2 (8.5) | Germany | Prospective, cohort. | NCT01686893 & NCT01693146 | Stable | COT | 60 min COT-washout-60 min HFNC | (2) |
| Jens et al. (2016) [21] | 67 (48, 19) | 60 (11.4) | Germany | Prospective, cohort. | NCT02504814 | Stable | Mechanical treatment | NR | (1), (3) |
| Jens et al. (2019)[22] | 94 (50, 44) | 65.3 (9.3) | Germany | M, RCT, crossover | NCT02007772 | Stable | NIV | 12 weeks including washout | (1), (2), (4), (5), (6) |
| Kazuma et al. (2018)[23] | 32 (16, 16) | 73.8 (6.9) | United states | M,RCT, crossover | NCT02545855 | Stable hypercapnic | LTOT | 12 weeks including washout | (4), (5) |
| Line et al. (2018)[24] | 200 (100, 100) | 71 (8.2) | Europe | RCT, crossover | NCT02731872 | Stable and acute exacerbation | LTOT | 12 months | (4), (5), (6) |
| Pisani et al. (2017)[25] | 14 (14, 14) | NR | Italy | Random, crossover | NCT02363920 | Stable | NIV | 150 min | (1), (3), (4) |
| Serena et al. (2016)[26] | 12 (12, 12) | 70 (8) | Italy | S,RCT, crossover | NR | Stable severe | Air condition | Three days including washout | (7) |
aOutcome measures include (1) respiratory rate, (2) FEV1, (3) tidal volume, (4) the oxygen partial pressure, (5) total score of St. George's respiratory questionnaire, (6) 6-minute walk test, (7) and exercise endurance time. NIV: noninvasive ventilation; H: HFNC; C:control. LTOT: long-term oxygen therapy; NCT: National Clinical Trial; S: single center; M: multicenter; RC: randomized controlled trial; NR: not reported; COT: conventional oxygen therapy.