OBSTRUCTIVE sleep apnoea (OSA) is a common yet frequently undiagnosed condition among people with Type 2 diabetes (T2D), despite its known association with heightened cardiovascular risk and premature mortality. Previous research has yielded mixed results regarding whether treating OSA with continuous positive airway pressure (CPAP) improves survival, particularly in those without diabetes. In populations with both T2D and OSA, studies have tended to focus on metabolic markers rather than long-term clinical outcomes. This large-scale Swedish study aimed to address that gap, finding that CPAP use was associated with a significantly lower risk of death over 14 years.
The study linked data from five national Swedish health registers, including adults with a diagnosis of T2D. Two groups were compared: 12,388 individuals with T2D who had been prescribed CPAP (and therefore had confirmed OSA), and 737,911 individuals with T2D who had never been prescribed CPAP (regardless of OSA status). A time-varying Cox regression model adjusted for baseline differences, including age, sex, and prior cardiovascular disease, as well as time-varying variables such as BMI, smoking, cholesterol, kidney function, blood pressure, and medication use. All-cause mortality was the primary outcome.
Over the 14-year follow-up period, 212,336 deaths occurred in the non-CPAP group compared to 764 in the CPAP group. After adjustment, CPAP use was associated with a 26% lower risk of all-cause mortality (hazard ratio [HR]: 0.74; 95% CI: 0.68–0.82; p<0.001). Despite the CPAP group being younger (mean age 58 vs 65) and having a higher mean BMI (34.7 vs 30.6), the association remained robust across the analysis.
These results support the potential benefit of CPAP therapy in improving long-term survival among people with T2D and suspected or diagnosed OSA. However, the authors caution that causal inference cannot be definitively established from observational data alone. As the control group likely included individuals both with and without OSA, the findings may in fact underestimate the true benefit of CPAP in those with confirmed OSA. From a clinical perspective, the study highlights the importance of routinely assessing for sleep apnoea in patients with T2D, who may otherwise miss out on a potentially life-extending intervention.
Reference
Agholme J et al. Long-term survival associated with continuous positive airway pressure in type 2 diabetes and obstructive sleep apnoea: results from Swedish national data. Abstract 336. EASD 2025. 15-19 September, 2025.
