Obstructive sleep apnea is typically characterized by upper-airway obstruction that results in episodic asphyxia, oxygen desaturation and disruption of the normal sleep pattern. Persons with obstructive sleep apnea often have daytime sleepiness with loss of concentration and memory impairment. An additional concern is the potential for cardiovascular morbidity and mortality resulting from hypoxemia. A standard therapy for obstructive sleep apnea is nasal continuous positive airway pressure (CPAP). D'Ambrosio and colleagues performed a prospective study to evaluate the effect of CPAP on quality of life in persons with obstructive sleep apnea.
The study included 23 men and six women referred to a university sleep laboratory for evaluation of sleep-disordered breathing. Those diagnosed with obstructive sleep apnea who did not have any other sleep disorders and had not received any treatments other than CPAP were included in the study. At baseline, all study subjects completed a Medical Outcomes Study Short Form-36 (SF-36), a survey tool that measures how patients perceive their own functional status, well-being and overall health. Questions are included to measure whether certain life or social activities have stopped or decreased as a result of health or emotional problems.
After the optimal amount of CPAP was established for each patient, therapy was maintained for eight weeks. At the end of eight weeks, the patients again completed the SF-36 assessment form.
The average age of the subjects was 44 years, with a range of 23 to 68 years. Many of the patients had comorbid illnesses, including heart disease, diabetes mellitus and hypertension, but all were stable at the time of initial evaluation and at follow-up. All of the study subjects had markedly low SF-36 scores compared with age-matched control subjects. The study subjects had severe obstructive sleep apnea with an average respiratory disturbance index of 77 events per hour, an arousal index of 67 arousals per hour and an arterial oxygen desaturation level that decreased from 94.1 percent while awake to 79.0 percent during sleep.
After eight weeks of CPAP for an average of six hours per night, the respiratory disturbance index decreased to four events per hour and the arousal index decreased to 13 arousals per hour. The mean oxygen saturation during sleep increased to 91.6 percent. All of the patients reported significant increases in vitality, social functioning and mental health compared with baseline. No correlation was apparent between the severity of the obstructive sleep apnea, respiratory disturbance index scores or oxygen saturation and improvement in SF-36 scores. However, patients with lower scores before treatment demonstrated greater improvement after treatment.
The authors conclude that patients with obstructive sleep apnea have marked impairments in all aspects of quality of life, including emotional and physical health, as well as social functioning. The use of CPAP can result in significant improvements in these areas. This improvement appears to occur regardless of the severity of the respiratory dysfunction.