Comparison 4. Heated humidification + fixed CPAP versus fixed CPAP alone.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Machine usage (hours/night)	6	277	Mean Difference (Fixed, 95% CI)	0.37 [0.10, 0.64]
2 Symptoms (Epworth Sleepiness Scale)	4	184	Mean Difference (Fixed, 95% CI)	‐0.34 [‐0.93, 0.26]
3 Withdrawals (parallel group trials/first arm cross‐over trials)	3	209	Odds Ratio (M‐H, Fixed, 95% CI)	1.00 [0.45, 2.24]
4 Apnoea Hypopnoea Index (events/hr)	1		Mean Difference (Fixed, 95% CI)	Totals not selected
5 Quality of life (SF‐36 questionnaire)	2	124	Mean Difference (IV, Fixed, 95% CI)	0.11 [‐6.97, 7.18]
6 Nasal symptoms (parallel group trials)	1		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
6.1 Runny nose	1	73	Odds Ratio (M‐H, Fixed, 95% CI)	0.32 [0.09, 1.15]
6.2 Congested or blocked nose	1	73	Odds Ratio (M‐H, Fixed, 95% CI)	0.19 [0.07, 0.51]
7 Nasal symptoms (parallel group trials)	2		Std. Mean Difference (IV, Fixed, 95% CI)	Subtotals only
7.1 Dry nose	2	103	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.38 [‐0.78, 0.01]
7.2 Runny nose	2	103	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.30 [‐0.69, 0.09]
7.3 Blocked nose	2	103	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.38 [‐0.78, 0.01]
7.4 Bleeding nose	2	103	Std. Mean Difference (IV, Fixed, 95% CI)	‐0.45 [‐0.99, 0.10]
8 Preference	1		Odds Ratio (M‐H, Fixed, 95% CI)	Totals not selected