Of course, all snoring isn’t necessarily bad (unless you are a sleep partner), but most of us have heard about Obstructive Sleep Apnea (OSA) and have pre-conceived notions about risk factors, prevalence and outcomes. It is safe to say, however, that obstructive sleep apnea is the ‘elephant in the room’ of cardiovascular risk. It is true that most individuals who have OSA are overweight or obese, as that is the most common risk factor. We know that the upper airway collapses in some people who have more tissue in the upper airway (tonsils, adenoids, tongue, palate and uvula). When the OSA sleeper lays in his/her back, gravity is not in their favor as muscles relax during sleep. When the sleeper attempts to breath in, the tissue obstructs resulting in snoring or gasping sounds and either a decrease in flow (hypopnea) or a cessation of airflow into the lungs (apnea). The more often this happens the more likely the sleeper is to develop the consequences of chronic intermittent hypoxia. OSA affects men about 2-3 times more commonly than women. An older study suggested that roughly 26% of a primary care population was potentially at risk of OSA, yet screen was very rare (1,2). If we look at one specific population, among an estimated 14 million US commercial drivers, 17–28% or 2.4 to 3.9 million are expected to have OSA (3). In this population the effects of sleep deprivation secondary to OSA can be disastrous.
A much more insidious and common occurrence of OSA is in people with diabetes. If we look at the type 2 diabetes patient population, the proportion at risk is significantly higher, due to the higher prevalence of older patients, and those with obesity. A recent review suggested the overall prevalence of diagnosed OSA in diabetic patients is approximately 71% based on the average data from five studies including a total number of nearly 1200 patients with type 2 diabetes (4). In 2008, the IDF Taskforce on Epidemiology and Prevention released a consensus statement that recommended a targeted approach to “screen individuals with type 2 diabetes and obesity for sleep disordered breathing (SDB)”. Briefly, the IDF recommended that healthcare professionals should consider the possibility of OSA in patients with type 2 diabetes and work in tandem with the local ‘sleep service’ to provide a clinically appropriate process of assessment, referral and intervention (5).
Several screening tests are available and include the Berlin Questionnaire, the STOP-BANG Questionnaire, and the Epworth Sleepiness Scale. This last screener may be less effective than the others primarily due to the fact that daytime sleepiness, while common, is not universal, and appears less often in women and in individuals with heart failure. I prefer the “Canadian modifications” of the STOP-BANG screening tool (6). Further diagnostic tests include the ‘gold standard’ sleep study (polysomnography), and within the last several years more and more products have been introduced that can be used as home diagnostic tests (7).
Studies have shown that cardiac remodeling occurs In OSA patients and that the changes are similar to predisposing changes for heart failure. There is a significant increase in cardiovascular risk from the downstream consequences of chronic intermittent hypoxia from repeated episodes of apnea or hypopnea during sleep: atherosclerosis, cardiovascular disease including conditions such as myocardial infarction, congestive heart failure, cerebrovascular accident, resistant hypertension, and cardiac arrhythmia, as well as cognitive dysfunction, depression, poor glucose control in diabetes and motor vehicle accidents to name just some of them.
So, the prevalence in people with diabetes is high, and the outcomes of cardiovascular morbidity and mortality are well described. Yet, the screening rate is abysmally low (in one study around 5%). Routine screening of diabetes patients should lead many more people to a diagnostic procedure and to CPAP as the most effective treatment. An old saying about how to eat an elephant is “one bite at a time”. In the case of OSA, I would submit that some of these bites are up to you. Pharmacists, involved in screening for OSA you ask (?) Of course! In this era of patient-centered care, how could a credible “diabetes practitioner” [yes, that’s you…] NOT screen patients for Obstructive Sleep Apnea!
- Hiestand DM, Britz P, Goldman M, Phillips B. Prevalence of symptoms and risk of sleep apnea in the US population: results from the National Sleep Foundation sleep in America 2005 poll. Chest 2006; 130:780 – 6.
- Grover M, et al. Identifying Patients at Risk for Obstructive Sleep Apnea in a Primary Care Practice. J Am Board Fam Med 2011;24:152–160
- Kales S, and Straubel,M. Obstructive Sleep Apnea in North American Commercial Drivers. Industrial Health 2014, 52, 13–24
- Pamidi S and Tasali E . Obstructive Sleep Apnea And Diabetes-IsThereALink_Pamidi FrontNeurol_2012_v3_Article128
- Seetho I, et al. Obstructive sleep apnoea in diabetes – assessment and awareness. British Journal of Diabetes 2014(3):105-108