Khanna 2003.

Methods	Randomised, parallel trial of nasal mask vs oral mask (Oracle) for treatment of OSAHS Duration of study: 8 weeks Method of randomisation: Not stated Allocation concealment: Unclear Blinding of participants: Not possible to blind mask type; Patients were not made aware that compliance was a major outcome Blinding of technician: Unclear Blinding of therapists: Not blinded Blinding of investigators: Unclear Withdrawals: Patients who abandoned treatment or used CPAP < 20 min/night were considered "dropouts" & removed from analyses in the month that treatment was not used 5 patients in the nasal group abandoned therapy before completion of 8 weeks. Complained of intolerable nasal congestion, throat inflammation, severe claustrophobia & excessive pressure from tight fitting mask. 6 patients in oral group dropped out. One stopped CPAP due to a major cerebrovascular accident. 3 patients complained of excessive oral dryness & gum pain, requiring change to nasal mask. 1 patient stopped using CPAP completely. 1 patient declined further participation. Intention to treat analysis: Not used
Participants	42 patients were enrolled and randomised. 38 patients analysed (nasal n = 17; oral n = 21) Recruitment setting not stated Inclusion criteria: Patients with a suspicion of OSAHS who had full polysomnography showing an AHI greater than or equal to 15/hr Exclusion criteria: severe cardiac disease, chronic pulmonary disease, significant psychiatric illness Male/Female: Nasal 11/6; Oral 13/8 Age range: Not stated Mean age (nasal): 50.9 ± 11.0 Mean age (oral): 52.5 ± 12.6 BMI (nasal): 34.2±6.0 BMI (oral): 34.9±5.4 AHI (nasal): 63±39.3 AHI (oral): 58.5±34.8
Interventions	Nasal mask (chosen from a large array for maximal pt comfort) vs Oral mask (Oracle, Fisher & Paykel Healthcare) CPAP machine: Both groups treated with the Fisher‐Paykel HC201 CPAP device with integrated heated humidifier & hour counter meter Diagnostic study: Full night polysomnography, with return for full night CPAP titration if eligible for inclusion. Therapeutic CPAP pressure: Level sufficient to abolish apnoeas & arousals on PSG (RDI less than or equal to 5 and oxygen saturation greater than or equal to 92%) Patients contacted by telephone within the first 3 days to assess if any major difficulties & pressure or mask adjustments done as requested by the treating physician. At the end of the first & second month, a respiratory therapist visited patients to check equipment & record compliance.
Outcomes	1) Compliance 2) Side effects (including oral dryness, nasal dryness, nasal congestion, gum pain, air leaks, gag reflex, bloating, mask dislodgement, headache, chest discomfort, sensation of excessive pressure, claustrophobia). Pts scored each on scale of 1(worst) to 5(best) or 1(worst) to 6(best). Side effects considered severe if scored less than or equal to 3. 3) Epworth sleepiness scale 4) Subjective data (Pt's overall satisfaction, level of functioning, complaints of sleepiness, feelings of being refreshed, quality of sleep, memory & concentrating abilities)
Notes	Age range of pts not stated Not all data on subjective scores were presented (i.e. overall satisfaction, level of functioning, complaints of sleepiness, quality of sleep, memory & concentrating ability) Not all data for side effects were presented, including gag reflex, bloating, mask dislodgement, headache
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised; other information not available
Allocation concealment (selection bias)	Unclear risk	Information not available
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information available
Incomplete outcome data (attrition bias) All outcomes	High risk	Patients who abandoned treatment or used CPAP < 20 min/night were considered "dropouts" & removed from analyses in the month that treatment was not used