Effect of Buteyko breathing technique on clinical and functional parameters in adult patients with asthma: a randomized, controlled study

Table 5 Between-group differences: healthy controls (HC) vs. Buteyko (BG) or usual treatment group (UT)

	Parameters	Time	HC vs. BG			HC vs. UT
	Parameters	Time	Mean difference	95% CI	ES	Mean difference	95% CI	ES
Breathhold	CP, s	BL	− 6.17	− 10.18; − 2.15	− 0.80	− 4.47	− 8.70; − 0.23	− 0.55
	CP, s	3-Mo FUP	2.50	− 1.47; 6.47	0.33	− 5.50	− 9.41; − 1.59	− 0.73
	MP, s	BL	− 12.07	− 17.24; − 6.89	− 1.21	− 6.77	− 12.86; − 0.68	− 0.57
	MP, s	3-Mo FUP	2.53	− 3.53; 8.60	0.22	− 9.23	− 14.61; − 3.85	− 0.89
Spirometry	FEV₁, %predicted	BL	− 0.24	− 0.34; − 0.14	− 1.26	− 0.13	− 0.21; − 0.05	− 0.83
Spirometry	FEV₁, %predicted	3-Mo FUP	− 0.21	− 0.30; − 0.11	− 1.11	− 0.12	− 0.21; − 0.04	− 0.73
Capnovolumetry	asinh(s2)	BL	− 0.04	− 0.20, 0.12	− 0.13	0.02	− 0.13, 0.17	0.07
	asinh(s2)	3-Mo FUP	− 0.05	− 0.19, 0.09	− 0.18	− 0.05	− 0.22, 0.12	− 0.16
	asinh(s3)	BL	0.12	0.06, 0.18	1.08	0.07	0.02, 0.12	0.74
	asinh(s3)	3-Mo FUP	0.09	0.05, 0.14	1.07	0.08	0.03, 0.13	0.79
	asinh(s3/s2)	BL	0.08	0.04, 0.11	1.16	0.04	0.01, 0.06	0.73
	asinh(s3/s2)	3-Mo FUP	0.05	0.03, 0.08	1.03	0.05	0.02, 0.08	0.8
	Threshold deadspace, mL	BL	− 7.3	− 20.8; 6.3	− 0.28	1.4	− 13.1; 15.9	0.05
	Threshold deadspace, mL	3-Mo FUP	3.0	− 10.5; 16.6	0.12	0.7	− 12.5; 14.0	0.03
Symptoms	NQ, score	BL	15.8	11.7; 19.9	1.97	12.1	8.8; 15.4	1.90
Symptoms	NQ, score	3-Mo FUP	7.5	3.6; 11.4	1.01	7.6	4.0; 11.1	1.11
Inflammation	FeNO, ppb	BL	11.6	2.0; 21.2	0.63	15.7	2.7; 28.7	0.63
Inflammation	FeNO, ppb	3-Mo FUP	16.8	5.5; 28.1	0.78	16.1	4.1; 28.2	0.70

The table shows between-group differences between healthy controls (HC, n = 30) and either Buteyko group (BG, n = 30) or usual treatment group (UT, n = 30). Differences refer to the values at baseline (BL) or 3-month follow-up (3-Mo FUP). ES Cohen’s d, CI confidence interval, CP control pause, MP maximum pause, FEV1 forced expiratory volume in 1 s, s2 slope of phase 2 in g/mol*L, s3 slope of phase 3 in g/mol*L, s3/s2 ratio of slopes of phases 3 and 2, asinh Areasinus hyperbolicus, NQ Nijmegen Questionnaire, FeNO fractional exhaled nitric oxide. The Asthma Control Questionnaire was omitted as it could not be sensibly asked in the HC group; the same was true for medication. Bold type indicates significant effects or differences with confidence intervals that do not contain zero

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