Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom severity
RCT	70 people with mild to severe OSAHS; baseline AHI 43.5	Frequency or severity of nasopharyngeal symptoms with CPAP plus humidification with CPAP alone Absolute results not reported	P >0.05		Not significant
RCT	70 people with mild to severe OSAHS; baseline AHI 43.5	Therapeutic pressure with CPAP plus humidification with CPAP alone Absolute results not reported	P >0.05		Not significant
RCT	70 people with mild to severe OSAHS; baseline AHI 43.5	Subjective response to CPAP treatment with CPAP plus humidification with CPAP alone Absolute results not reported	P >0.05		Not significant
Systematic review	54 people; mean baseline AHI: 50 in CPAP alone group v 42 in CPAP plus humidification group Data from 1 RCT	Quality of life and nasal resistance with CPAP plus humidification with CPAP Absolute results not reported	Reported as not significant P value not reported See further information on studies for methodological weaknesses		Not significant