Undiagnosed, and untreated, Obstructive Sleep Apnea (OSA) may contribute to hypertension and other cardiovascular morbidity, sleepiness, motor accidents, impaired cognitive function, and increased mortality.

Australian data estimating the prevalence of OSA associated with daytime sleepiness at 3% in adult men dates from 20 years ago when the prevalence of overweight and obesity was 20% lower than currently. The majority of OSA is undiagnosed. Despite a four-fold increase in government-funded polysomnography since 1995 the scale of the problem of under-recognition of OSA is unknown.

To address this question we determined the prevalence and severity of sleep disordered breathing and related co-morbidities in a representative population-based cohort of men aged over 40yrs (n=1829). In 2011-12, full in-home unattended polysomnography were done in 851 randomly selected men from the cohort who did not have a previous diagnosis of OSA and were scored by a single experienced scorer according to current AASM (alternate) criteria.

Among all cohort participants, n= 184 (11.3%) self-reported a previous diagnosis of OSA on a sleep study. Among the sleep study participants (mean age 59.6 years), n=451 (53%) had an AHI ≥10, with AHI 20-29 in 14.0% and AHI ≥30 in 12.3%. Among those with AHI ≥10, n=199 (44.1%) reported frequent diurnal sleepiness. In a multivariable regression model undiagnosed OSA was significantly associated with older age; central adiposity; hypertension (OR 1.5, 95% CI 1.1-2.1); depression (OR 2.2, 95% CI 1.4-3.6); and financial stress (OR 1.6, 95% CI 1.0-2.7). OSA had a significant negative impact on quality of life.  

The burden of undiagnosed OSA is substantial and the capacity currently available within the healthcare system to investigate and diagnose OSA is likely to be inadequate, particularly outside urban areas. This highlights an important public health problem that demands innovative methods to extend community diagnosis. Recent Australian trials have demonstrated a cost-effective model of OSA investigation and management in primary care.