Obstructive sleep apnea has a number of potential short- and long-term complications, but treatment of sleep apnea has been associated with improvement or elimination of these complications.
Multiple studies have demonstrated a strong association with severe obstructive sleep apnea and cardiovascular complications, including an increased risk of high blood pressure (hypertension), heart attack (myocardial infarction) and stroke (cerebrovascular accident).
Fortunately, studies also show that adequate treatment of sleep apnea reduces these cardiovascular risks. In order for treatment to be “adequate,” the positive airway pressure therapy must be in use for at least four hours per night on at least five nights per week (although more use is better). Oral appliances are similar in that they need to be worn comfortably and remain in place over the course of the night to obtain benefit and reduce risk of complications.
Other Health-Related Complications
Studies have shown that obstructive sleep apnea is also associated with a greater risk of cancer (among those younger than 65 years of age), gastroesophageal reflux and insulin resistance (a condition that may contribute to non-insulin-dependent diabetes). Limited evidence indicates that sleep apnea may contribute to erectile dysfunction. There are no higher-level studies examining the extent to which treatment reduces these risks.
For patients undergoing certain types of surgery, untreated sleep apnea has been associated with a greater likelihood of pulmonary or cardiovascular complications, such as those related to breathing or heart rhythms. Treatment of sleep apnea has been shown to normalize these risks.
Behavioral Impacts of Sleep Apnea
Sleep apnea disrupts the quality of sleep, leading to behavioral impacts like sleepiness, fatigue, difficulties with memory or concentration, depressive symptoms and decreased quality of life. Here, the benefits of treatment are controversial. Most patients with these symptoms experience improvement with adequate treatment. However, the APPLES (Apnea Positive Pressure Long-Term Efficacy Study) randomized trial showed only minimal benefit in behavioral measures after treatment with positive airway pressure therapy.
This followed some earlier studies showing that many patients have persistent symptoms of sleepiness or decreased quality of life, in spite of thorough treatment (such as wearing positive airway pressure therapy for eight hours per night). There is a suggestion that sleep apnea may create some effects that become permanent or semipermanent over time, limiting the ability of treatment to reduce all of the effects of sleep apnea.