OSA Symptoms and Clinical Consequences
The true medical side effects of untreated OSA are vast and just starting to be recognized. Side effects range from snoring and headaches to diabetes and stroke, sleep apnea is a killer!
In a 2005 study, Marin et al found that severe untreated OSA was associated with a 287% increased risk of cardiovascular morbidity defined by fatal myocardial infarction or stroke. The authors also concluded that untreated severe OSA increased the risk of cardiovascular morbidity by 317%.
Treatment saves lives! A study of 875 diagnosed OSA patients showed that those who wore their CPAP at least 6 hours per night had a significantly higher survival rate at 5 years (96%) compared with those who did not wear their CPAP (85%).
Excessive Daytime Tiredness
Excessive daytime tiredness is the most common symptom of sleep apnea. Screening for excessive daytime tiredness is essential for all medical and dental practices who wish to be involved in the diagnosis and treatment of sleep disordered breathing. This screening is typically done with an Epworth Sleepiness Scale (ESS). See the protocol section for copies of this form and scoring guidelines.
People with excessive tiredness due to OSA will be noticeably fatigued. They will sometimes have problems staying awake at work and in social situations. Tired driving is a dangerous side effect that needs to be considered. As of 1995 only Maine, Texas and California had specific guidelines regarding driving and OSA diagnosis. Canada has guidelines requiring routine follow up and proof of treatment.
Interestingly, in one study (Chervin, 2000) patients complained of lack of energy 62% of the time, fatigue 57% of the time and sleepiness only 47% of the time.
Snoring is not necessarily a clinical consequence of OSA, but it is a major symptom that must not be overlooked. Snoring is the second largest complaint bringing people into sleep labs and the primary complaint of bed partners in North America. Frequently it is the husband or wife who initiates the diagnostic process because of the desire to eliminate snoring.
Snoring itself does not mean apnea is present, it does however indicate that the patient has a narrow, collapsible, airway. A simple question of “Do you snore?” should be asked of every patient as part of a history/records screening. Conservatively it is estimated that 40% of adults snore.
Some studies strongly suggest that for some people sleep disorders, including apnea, may be the underlying causes of some chronic headaches. In some patients with both chronic headaches and apnea, treating the sleep disorder has been known to cure the headache, even the very severe and disabling form known as a cluster headache.
Esophageal Reflux (GERD)
Many studies point to a link between GERD and OSA. When a person’s airway collapses during an OSA event a few key things occur that could bring on acid reflux: There is significant struggle and effort to breathe. This can be seen on a patient and monitored by looking at chest and abdominal efforts. The contraction of the diaphragm and pronounced efforts to inhale air squeeze the stomach and force acid up the esophagus. At the same time, there is negative pressure being created by the efforts to inhale. Because the obstruction is typically in the extreme upper airway, the negative pressure created, acid can rise up the esophagus, causing GERD.
Systemic hypertension is observed in 50-70% of patients with OSA. Several large cross-sectional studies have demonstrated that OSA is a risk factor for developing hypertension independent of obesity, age, alcohol intake, and smoking. These same studies found a direct relationship between the degree of OSA and the level of hypertension. Other studies have found that when treated with CPAP, blood pressure in OSA patients decreases.
Weight gain and obesity are both risk factors for OSA, they are also clinical consequences. It has been documented that people suffering from OSA feel as though they have significantly less energy, are fatigued, and exhibit excessive sleepiness. All these things are contradictory to a healthy, active, lifestyle.
Some experts note that OSA can have an adverse effect on diet. People may feel compelled to intake sugars and carbs for the short-term energy boosts to help make it through the day.
As is the case with many hormones, Leptin is released into the body during stage 4 sleep. Leptin is a natural appetite suppressant protein. People with OSA have fragmented, disrupted, sleep patterns and as a result many hormones and proteins are not released into the body.
Insulin resistance: Multiple studies have shown that patients with OSA have increased glucose levels and increased insulin resistance (Punjabi, 2002; Punjabi, 2004). The most recent study was from the Sleep Heart Health Study. In this study of 2000 research subjects, the prevalence of diabetic 2-hour glucose tolerance values rose from 9.3% in the group with an AHI less than 5 to 15% in the group with an AHI greater than 15; insulin resistance was also highest in this group. Correlations were also noted with the degree of oxygen desaturation at night, indicating that the OSA may contribute to insulin resistance as a result of the hypoxemia that occurs with the syndrome.
This topic is still being debated. It has, however, been noted by the National Sleep Foundation that up to 80% of dementia patients suffer from sleep disordered breathing.
A strong genetic connection between Alzheimer’s and sleep apnea was reported June 13 in the Journal of the American Medical Association by Emmanuel Mignot, MD, PhD, director of the Center for Narcolepsy at Stanford’s Center for Human Sleep Research, and Greer Murphy, MD, PhD, director of the Neurochemistry/ Genetics Core of the Stanford Alzheimer’s Disease Center. Their research showed that a particular gene linked to sleep apnea also predisposes carriers to the development of Alzheimer’s.
A 2005 study found that OSA was associated with a significant increase in the risk of sudden death between the hours of midnight and 6am, as compared with the general population.
Approximately 50% of heart failure patients experience sleep-disordered breathing (SDB) with Central Sleep Apnea or Obstructive Sleep Apnea (Sinn DD et al, 1998)
A large epidemiologic study (the Sleep Heart Health Study) is currently being conducted to provide more definitive data regarding the relationship between sleep apnea and cardiovascular morbidity. Initial findings from the Sleep Heart Health Study indicate that a relationship exists between severe OSA and an increased risk of coronary artery disease, congestive heart failure, and stroke (Shahar, 2001). This study is ongoing to determine if the presence of OSA is associated with the development of cardiovascular morbidity.
As many as 63% of stroke sufferers also experience Sleep Disordered Breathing (SDB) (Bassetti, 1999). Stroke sufferers are as many as 5 times more likely to have SDB as controls. Stroke sufferers with SDB have worse functioning outcomes and higher mortality after 1 year than those without SDB.
In the Wisconsin Cohort Study patients with an AHI greater than 20 was associated with an increased risk of stroke over a 4 year follow up.