Neither the severity of obstructive sleep apnea (OSA) nor sleep duration are associated with measures of insulin sensitivity or β-cell responses in adults with either prediabetes or recently diagnosed but untreated type 2 diabetes (T2D), according to study results published in Diabetes Care.
Using data collected during the run-in and baseline phases of the RISE Adult Medication Study, investigators analyzed both insulin sensitivity and β-cell responses to identify which components of the glucose regulatory pathway were associated with OSA and sleep duration.
The final cohort included 221 participants (57.5% men; mean age, 54.5±8.7 years; BMI, 35.1±5.5 kg/m2) who completed the baseline procedures for the RISE study, polysomnography, and 1 week of actigraphy. Of these patients, 73% had prediabetes and 27% had recently diagnosed, treatment-naive T2D.
As measured via wrist actigraphy, OSA duration was 6.6±1 hours a night; 22% had a mean sleep duration of less than 6 hours a night. Mean Epworth Sleepiness Scale score was 8.5±4.6, with 37.1% of participants having a score indicative of excessive daytime sleepiness.
A large majority (89%) of participants had OSA (mild, 20%; moderate, 28%; severe, 41%); 29% of participants reported having a continuous positive airway pressure (CPAP) machine at home, but 16 people within this group had never used it. Among the 49 participants who did use their CPAP, 41 self-reported adherence of ≥4 hours for ≥ 5 nights/wk.
Participants with untreated, severe OSA had a higher waist circumference and waist-to-hip ratio compared with participants without OSA or with mild but untreated OSA. The results of unadjusted analyses indicated no differences in hyperglycemic clamp-derived variables across OSA categories.
Participants with moderate or severe untreated OSA also trended toward lower insulin sensitivity, quantified by insulin sensitivity (P =.051). These participants also had higher levels of insulin sensitivity measured by the Homeostatic Model Assessment for Insulin Resistance (P =.003). No evidence of lower insulin resistance in participants who self-reported CPAP adherence was noted.
The results of multiple regression analyses using continuous variables, higher apnea-hypopnea index (AHI), and higher 3% and 4% oxygen desaturation indices were associated with higher glycated hemoglobin (HbA1c). A 40-unit higher AHI was associated with a 0.12% higher absolute value of HbA1c. Higher AHI, 4% oxygen desaturation index, and microarousal index were all associated with increased incremental glucose area under the curve, which remained significant after excluding participants who were adherent to CPAP therapy.
The researchers noted no sex-based differences in the association of OSA and sleep duration with any outcomes.
Study limitations include potential bias resulting from the use of baseline analyses, a lack of directly quantified body fat, and a lack of objective CPAP adherence data. Causality cannot be determined because of the cross-sectional nature of the analysis.
“OSA and short sleep duration are highly prevalent in [adults with obesity] with prediabetes and recently diagnosed untreated [T2D], but… there were no significant associations between OSA severity or short sleep duration with various components of the glucose regulatory pathway,” the researchers concluded. “In [individuals with obesity], treatment of OSA is important, but our results underscore the need for a comprehensive approach that includes additional interventions, particularly exercise and weight loss.”
Disclosure: This clinical trial was supported by Allergan, Inc.; Apollo Endosurgery, Inc.; Abbott Laboratories; Novo Nordisk; and Philips Respironics. Please see the original reference for a full list of authors’ disclosures.
Mokhlesi B, Tjaden AH, Temple KA, et al; for the RISE Consortium. Obstructive sleep apnea, glucose tolerance, and β-cell function in adults with prediabetes or untreated type 2 diabetes in the Restoring Insulin Secretion (RISE) Study. Diabetes Care. 2021;44(4):993-1001. doi:10.2337/dc20-2127