The clinical predictors of sleepiness correlated with the multiple sleep latency test in an Asian Singapore population.

STUDY OBJECTIVES

To explore the clinical predictors of sleepiness as objectively determined by the Multiple Sleep Latency Test with the Epworth Sleepiness Scale, age, body mass index, and overnight polysomnographic parameters at a tertiary referral center Sleep Disorders Unit.

DESIGN

Retrospective, consecutive case series review.

SETTING

A multidisciplinary sleep disorders unit in Singapore General Hospital, a tertiary-care university-affiliated hospital.

PATIENTS

72 consecutive patients evaluated for sleep disorders with overnight polysomnograms and Multiple Sleep Latency Tests between March 2002 and September 2002.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Mean sleep latency on the Multiple Sleep Latency Test was 9.0 +/- 4.4 minutes, and mean Epworth Sleepiness Scale score was 10.8 +/- 5.8. On univariate analysis, mean sleep latency on the Multiple Sleep Latency Test showed a significant negative correlation with the Epworth Sleepiness Scale score, apnea-hypopnea index, body mass index, arousal index, and time spent below 90% oxygen saturation during overnight polysomnography. After performing multiple linear regression, only Epworth Sleepiness Scale score and apnea-hypopnea index remained significantly correlated (P = .039 and P = .008, respectively). An Epworth Sleepiness Scale score of 8 or above predicted a mean sleep latency on the Multiple Sleep Latency Test of less than 10 minutes with a sensitivity of 73.9% and specificity of 50.0%.

CONCLUSIONS

The Epworth Sleepiness Scale and apnea-hypopnea index are useful predictors of sleepiness in our Asian Singapore population.