Table 5.

Subgroup meta-analysis of main outcomes in patients with asthma in OSA group and non-OSA group

Outcomes and subgroups	No. of studies	Population	WMD	95%CI	I2 (%)	PH	Statistical model	PZ	Between-group P value
FEV1 (%)
All	13	1111	− 2.29	− 4.91, 0.33	75.9	< 0.001	Random	0.086	–
Age
Children	4	318	− 4.33	− 7.82, − 0.83	48.6	0.120	Random	0.015	0.210
Adult	9	793	− 1.24	− 4.56, 2.08	78.1	< 0.001		0.464	–
Severity of OSA
AHI ≥ 1 or 5/h	11	1013	− 3.04	− 5.68, − 0.40	77.3	< 0.001	Random	0.024	0.015
AHI ≥ 15/h	2	98	7.69	− 0.54, 15.93	0	0.557		0.067	–
Severity of asthma
Routine	8	714	− 2.56	− 5.83, 0.70	72.6	0.001	Random	0.124	0.863
Uncontrolled	4	307	− 1.34	− 7.23, 4.54	86.1	< 0.001		0.655	–
FVC (%)	13	1111	0.01	− 1.92, 1.94	0	0.573	Fixed	0.992	–
FEV1/FVC (%)
All	9	782	− 0.82	− 3.08, 1.44	69.0	0.001	Random	0.477	–
Age
Children	2	141	− 4.75	− 8.55, − 0.95	0	0.446	Random	0.014	0.035
Adult	7	641	0.04	− 2.28, 2.37	67.3	0.005		0.972	–
Severity of OSA
AHI ≥ 1 or 5/h	7	684	− 1.65	− 4.03, 0.74	72.0	0.002	Random	0.176	0.017
AHI ≥ 15/h	2	98	4.83	0.05, 9.61	0	0.482		0.047	–
Severity of asthma
Routine	6	589	− 1.11	− 4.63, 2.41	76.6	0.001	Random	0.536	0.254
Uncontrolled	2	94	1.01	− 0.27, 2.30	0	0.873		0.123	–
FEF25–75%	3	179	− 5.15	− 12.72, 2.42	27.0	0.254	Fixed	0.183	–
ACT score	4	385	− 0.37	− 0.74, 0.00	0	0.688	Fixed	0.050	–

WMD; weighted mean difference, CI; confidence interval, PZ; P value for Z test, PH; P value based on Q test for between-study heterogeneity, %FEV1; forced expiratory volume in one second (%predicted), OSA; obstructive sleep apnea, AHI; apnea/hypopnea index, FVC%; forced vital capacity (%predicted), FEF_25-75%; forced expiratory flow (25–75% of VC), ACT; asthma control test