Context: Few prospective intervention studies have examined the effect of continuous positive airway pressure (CPAP) therapy on cardiovascular disease (CVD) risk factors in diabetes.
Objective: Our objective was to determine whether CPAP improves CVD risk factors in patients with type 2 diabetes and obstructive sleep apnea (OSA).
Design and setting: This was a randomized parallel group intervention trial in an urban Australian community.
Patients: Fifty-nine participants of the Fremantle Diabetes Study Phase II at high risk for OSA consented to confirmatory polysomnography followed by randomization to a 3-month CPAP intervention initiated early (<1 wk) or late (1-2 months).
Main outcome measures: Patients were assessed before and 1 and 3 months after CPAP started. Tests for repeated measures were used to compare variables of interest over time.
Results: Forty-four patients (75%) completed the study. Their mean ± sd age was 66.1 ± 8.8 yr, and 61.4% were male. Completers and noncompleters had similar age, sex, diabetes duration, apnea-hypopnea index, and Epworth Sleepiness Scale (P ≥ 0.29). There were no differences in outcome between early and late randomization, and the data were pooled. The Epworth Sleepiness Scale decreased between entry and 1 month [-4.8 (-6.5 to -3.1), P < 0.001]. Blood pressure improved between entry and 3 months (from 149 ± 23/80 ± 12 to 140 ± 18/73 ± 13 mm Hg; P ≤ 0.007). Pulse rate declined within the first month [-6 (-10 to -2) beats/min, P = 0.002]. Glycemic control and serum lipids, which were mostly within recommended target ranges at entry, did not change.
Conclusions: Three months of CPAP in community-based people with type 2 diabetes significantly decreased blood pressure and pulse rate but did not influence metabolic control.