Is insomnia an independent predictor of obstructive sleep apnea?
BACKGROUND
Obstructive sleep apnea (OSA) is a disorder with high prevalence in primary care. However, little research exists on screening for OSA in primary care samples.


METHODS
One hundred family medicine patients completed standardized symptom and demographic questionnaires and a structured clinical interview for sleep disorders. Two-step logistic regression was performed to determine the independent predictive value of insomnia for clinical identification of OSA. Additional t tests were computed to examine age and sex patterns of insomnia.


RESULTS
A model including body mass index and daytime sleepiness predicted OSA status (χ(2) = 18.63; P < .001) and explained 27% of the variance in OSA clinical diagnosis. Addition of insomnia scores to the model significantly improved predictive utility (χ(2) = 25.79; P < .001) and explained 36% of the variance in OSA. Insomnia scores were higher for women compared with men (P = .033) and women with OSA compared with women without OSA (P = .007).


CONCLUSIONS
Inquiry regarding insomnia may improve clinical identification of OSA when screening for OSA in primary care. This finding possibly is unique to the evaluation of OSA in a primary care versus sleep laboratory sample. The predictive utility of insomnia may be specific to women.
Lynn Institute for Healthcare Research, Colorado Springs, CO 80907, USA. rglidewell@lhsi.net
Robert N
RN
Glidewell
Emily K
EK
Roby
William C
WC
Orr
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000175:diagnosis*; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications*; D011795:Surveys and Questionnaires; D055815:Young Adult