Obstructive sleep apnea-hypopnea syndrome is characterized by excessive daytime sleepiness, disruptive snoring, repeated episodes of upper airway obstruction during sleep and nocturnal hypoxemia. Sleep apnea is not readily identified because the techniques needed to recognize the disorder—use of diagnostic equipment or a patient interview to obtain a sleep history—require significant time and training. The Berlin Questionnaire, developed in 1996, includes a series of questions about risk factors for sleep apnea, including snoring behavior, waketime sleepiness or fatigue, and obesity or hypertension. For a sample of the Berlin Questionnaire, see the accompanying figure on page 1828. Netzer and associates evaluated the usefulness of the Berlin Questionnaire in the primary care setting to identify patients with sleep apnea.

Office staff members at five participating practices distributed the Berlin Questionnaire to 1,000 consecutive patients. Patients were also asked to provide data about age, weight, height, sex, neck circumference and ethnicity. Obesity was determined by calculating body mass index (BMI). Responses to questions allowed patients to be grouped into high- and low-risk groups based on their responses in three symptom categories: snoring, waketime sleepiness, and hypertension or above-normal BMI. Portable monitoring of respiratory disturbances during sleep was offered to a randomized segment of both groups. Patients in the high-risk group were thought to be more likely to have a respiratory disturbance index (RDI), meeting the criteria for obstructive sleep apnea-hypopnea syndrome.

Of the 1,008 patients surveyed, 744 were included in the analysis. Information about neck circumference and ethnicity was not provided consistently, so this information was not included in the analysis. Of the 744 respondents, 388 reported that they snored, 223 denied snoring, 118 did not know and 15 did not respond. A total of 279 respondents reported waketime tiredness or fatigue. Men were more likely than women to snore, stop breathing during sleep and report drowsiness while driving. Women reported feeling tired more often than men. Forty-four percent of men were considered at high risk, compared with only 33 percent of women. In addition, high-risk patients had a higher BMI, snored loudly, had a history of hypertension, felt tired during waketime and tended to fall asleep while driving. The risk grouping predicted RDI better than any single symptom category.

The authors conclude that the Berlin Questionnaire can be used to identify patients who meet or exceed the RDI values used in diagnostic classifications of obstructive sleep apnea-hypopnea syndrome, even in the absence of a physician encounter. However, physician judgment is essential to initiate management, identify unusual cases and detect other possible causes for waketime sleepiness.

editor's note: In an accompanying editorial, Millman emphasizes that sleep apnea is not readily identified in patients. Educating physicians about sleep disorders can increase awareness and appropriate referrals for sleep testing.—r.s.