Background: Although sleep apnea is common, it often goes undiagnosed in pr
imary care encounters.
Objective: To test the Berlin Questionnaire as a means of identifying patie
nts with sleep apnea.
Design: Survey followed by portable, unattended sleep studies in a subset o
f patients.
Setting: Five primary care sites in Cleveland, Ohio.
Patients: 744 adults (of 1008 surveyed [74%]), of whom 100 underwent sleep
studies.
Measurements: Survey items addressed the presence and frequency of snoring
behavior, waketime sleepiness or fatigue, and history of obesity or hyperte
nsion. Patients with persistent and frequent symptoms in any two of these t
hree domains were considered to be at high risk for sleep apnea. Portable s
leep monitoring was conducted to measure the number of respiratory events p
er hour in bed (respiratory disturbance index [RDI]).
Results: Questions about symptoms demonstrated internal consistency (Cronba
ch correlations, 0.86 to 0.92). Of the 744 respondents, 279 (37.5%) were in
a high-risk group that was defined a priori. For the 100 patients who unde
rwent sleep studies, risk grouping was useful in prediction of the RDI. For
example, being in the high-risk group predicted an RDI greater than 5 with
a sensitivity of 0.86, a specificity of 0.77, a positive predictive value
of 0.89, and a likelihood ratio of 3.79.
Conclusion: The Berlin Questionnaire provides a means of identifying patien
ts who are likely to have sleep apnea.