The impact of high-flow nasal cannula oxygen therapy on exercise capacity in fibrotic interstitial lung disease: a proof-of-concept randomized controlled crossover trial

Table 4 Subgroup analysis of endpoints in HFNC good responders

N = 13	VM	HFNC	Difference (95% CI)	P-value^**
Primary endpoint
Endurance time, min	6.4 (4.5–8.3)	7.8 (5.8–9.7)	1.4 (0.0–2.7)	0.046
Secondary endpoint
Min SpO₂, %	89.7 (84.3–95.0)	88.6 (83.2–93.9)	−1.1 (−3.4–1.2)	0.319
Max HR, bpm	124.2 (112.4–136.1)	120.5 (108.6–132.4)	−3.7 (− 14.8–7.4)	0.478
Isotime Borg scale (dyspnea)	6.7 (5.3–8.1)	6.4 (5.0–7.8)	−0.3 (− 1.6–1.0)	0.632
Isotime Borg scale (leg fatigue)	6.3 (4.5–8.1)	6.0 (4.2–7.7)	− 0.4 (− 1.8–1.1)	0.583
Final Borg scale (dyspnea)	7.3 (5.8–8.8)	7.2 (5.7–8.6)	− 0.2 (− 0.5–0.2)	0.153
Final Borg scale (leg fatigue)	6.6 (4.7–8.6)	6.9 (4.9–8.8)	0.3 (− 0.8–1.4)	0.614
Patient comfort of device	8.4 (7.2–9.6)	7.3 (6.1–8.5)	− 1.0 (−2.7–0.7)	0.220

Data are presented as number (%) or mean (95% CI)
HFNC high-flow nasal cannula, HR heart rate, SpO₂ saturation of peripheral oxygen, VM venturi mask
^*Good responder was defined as a patient with > 100 s or 33% improvement in endurance time from baseline CWRET,
^**Calculated by generalized linear mixed-effects model with fixed factors for each device, sequence, and period, and a random factor for subject within sequence

ISSN: 1471-2466