. 2017 Oct 10;12:2977–2985. doi: 10.2147/COPD.S148422

Table 3.

Subgroup analysis

Therapeutic aim (none vs reducing PaCO₂)	Reference numbers	Number of patients (treatment/control)	Treatment effect (WMD 95% CI)	Study heterogeneity
Therapeutic aim (none vs reducing PaCO₂)	Reference numbers	Number of patients (treatment/control)	Treatment effect (WMD 95% CI)	I²	P-value
Mortality	5, 11, 24, 25/12, 26	401/396	0.78 (0.54 to 1.13)	0.19	0.003
PaCO₂	5, 11, 24, 25, 27/12, 26	300/296	−3.73 (−5.83 to −1.64)	0.0005	93.3%, 0.0001
PaO₂	5, 11, 24, 25, 27/12, 26	193/192	0.54 (−0.26 to 3.14)	0.69	0.0%, 0.91

Notes: Treatment, treatment group; control, control group.

Abbreviations: PaCO₂, partial pressure of carbon dioxide; PaO₂, partial pressure of oxygen; WMD, weighted mean difference; CI, confidence interval.