Hudgel 2000.

Methods	Randomised, single‐blind, cross‐over study. Method of randomisation: hospital number (odd versus even last digit) Paired t test used for continuous data
Participants	N = 60 (53 with OSA and 7 with UARS). 21 withdrawals 2 stopped due to medical complications (not stated) and the rest did not complete the study. Further 6 did not have machine usage data. (21 M/18 F). Total number of OSA patients completing trial is 29. Data analysed for 33 patients which included 4 patients with UARS Mean age: 46 years; AHI 30; BMI: 42 kg/m2 Inclusion criteria: diagnosed OSA or UARS (confirmation by polysomnography) Exclusion criteria: prior CPAP treatment, facial/pharyngeal abnormalities requiring surgery, chronic airways disease necessitating bronchodilator usage, obesity hypoventilation syndrome, shift workers, congestive heart failure, seizure disorder, mental retardation, sedative/antidepressant/hypnotic treatment
Interventions	Auto‐CPAP versus fixed CPAP. No washout Study duration: 2 x 12 week treatment periods
Outcomes	Treatment pressure  Symptoms (ESS) Machine usage (hours of usage, % nights used effectively & % days used) AHI
Funding & conflicts of interest statements	Not provided
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Hospital number (odd versus even last digit)
Allocation concealment (selection bias)	High risk	Study investigators likely to be aware of treatment group assignment
Blinding of participants and personnel (performance bias) Machine usage, symptoms, quality of life, withdrawal, adverse effects	High risk	Study investigators likely to be aware of treatment group assignment
Blinding of participants and personnel (performance bias) AHI, blood pressure, treatment pressure	Low risk	These outcomes unlikely to be affected by study design
Blinding of outcome assessment (detection bias) Machine usage, symptoms, quality of life, withdrawal, adverse effects	High risk	Study investigators likely to be aware of treatment group assignment
Blinding of outcome assessment (detection bias) AHI, blood pressure, treatment pressure	Low risk	These outcomes unlikely to be affected by open‐label design
Incomplete outcome data (attrition bias) All outcomes	High risk	High withdrawal rate and non‐completers not included in analysis
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	No concerns identified