Long-term CPAP use confers benefits for diabetes in sleep apnoea patients
Regular, long-term use of continuous positive airway pressure (CPAP) protects against the risk of developing type 2 diabetes mellitus (T2DM) in obstructive sleep apnoea (OSA) patients, a study suggests.
The study included 1,206 OSA patients who underwent overnight sleep studies and clinical assessments, among whom 152 developed diabetes over a median follow-up of 7.3 years. Researchers obtained data for incident T2DM and CPAP usage from the territory-wide electronic health administration system and records of protocolized evaluation of CPAP adherence at the sleep clinic.
Cox regression models showed that the risk of incident T2DM was higher in patients with untreated moderate OSA (hazard ratio [HR], 2.01, 95 percent CI, 1.06–3.81) and in those with severe OSA (HR, 2.62, 1.40–4.93), with a trend to plateau in the latter. There was no interaction observed between OSA and obesity.
About one-third of patients with moderate-to-severe OSA achieved regular CPAP use, which led to a reduction in diabetes incidence from 3.41 to 1.61 per 100 person-years. CPAP use also reduced the risk estimate for incident T2DM in OSA patients relative to those with no OSA, even after adjusting for various baseline metabolic risk factors and subsequent body weight change.
Intermittent hypoxia and sleep fragmentation, the two major characteristics of OSA, can lead to imbalances in glucose metabolism via several mechanisms including activations of the sympathetic nervous system and hypothalamic-pituitary axis, and changes in the inflammatory pathways. [ILAR J 2009;50:289-306]
With regard to CPAP therapy, some studies support the hypothesis that the degree of obesity and the amount of CPAP use may be important factors in the metabolic response to CPAP. Identification of metabolic phenotypes of OSA who are more likely to benefit from CPAP therapy may play a significant role in the clinical management and care of patients with prediabetes and T2DM. [Front Neurol 2012;3:126]