A common sleep therapy used to treat patients with obstructive sleep apnea (OSA) may actually have a protective effect against death related to cardiovascular disease.
In a new study published in the June issue of CHEST, the peer-reviewed journal of the American College of Chest Physicians, patients with OSA who were treated with continuous positive airway pressure (CPAP) had significantly fewer cardiovascular disease-related deaths and cardiovascular-related events than untreated patients.
"Research has shown that patients with OSA have an increased incidence of death or events related to cardiovascular disease, particularly hypertension," said Walter McNicholas, MD, FCCP, St. Vincent's University Hospital, Dublin, Ireland. "Short-term use of CPAP therapy has resulted in health and quality-of-life benefits in patients with sleep apnea, including improved daytime alertness and mental functioning. Extended CPAP therapy may have additional benefits for patients with OSA by protecting them against cardiovascular disease related to the sleep disorder."
Researchers from St. Vincent's University Hospital in Dublin followed 168 patients with OSA for an average of 7.5 years to monitor the long-term effect of CPAP therapy on cardiovascular disease. Researchers compared the number of cardiovascular-related events and deaths between 107 patients who used CPAP therapy and 61 patients who never tolerated or stopped CPAP therapy for at least five years. During the follow-up period, there was a significant excess of cardiovascular deaths among the untreated patients (14.8 percent), compared to CPAP group (1.9 percent). The total number of cardiovascular events, including death, congestive heart failure, hypertension, and stroke, also was significantly greater in the untreated group (31 percent), compared to the CPAP group (18 percent). There were no significant differences between the CPAP group and the untreated group in terms of age, body mass index, and cardiovascular risk factors at baseline; however, patients in the untreated group had significantly lower apnea scores and more had undergone nasal surgery prior to diagnosis of OSA.
"The association between OSA and cardiovascular disease is not fully understood. It is possible that the constant fluctuation in blood oxygen levels caused by OSA may contribute to arterial inflammation, blood flow obstruction, and, eventually, increased hypertension and cardiovascular-related events," said Dr. McNicholas. "Through the long-term relief of OSA, patients may decrease the subtle physical effects of OSA, thereby decreasing the overall incidence of cardiovascular morbidity and mortality."
"Sleep apnea is associated with several modifiable risk factors, including obesity, smoking, and excessive alcohol use," said Paul A. Kvale, MD, FCCP, President of the American College of Chest Physicians. "Although it is important to manage OSA through treatments, such as CPAP, physicians and patients must take steps to identify and modify risk factors that may be contributing to the disorder."