['To compare 2 composite indices of sleep apnea disease burden with the commonly used apnea-hypopnea index with regard to baseline measurement of subjective and objective disease burden.', 'Cross-sectional study.', 'Tertiary academic medical center sleep laboratory.', 'Patients with suspected diagnosis of sleep apnea undergoing first diagnostic polysomnography. Subjective data were collected via validated questionnaires; objective data were obtained by standardized physical examination, chart extraction, and polysomnography. Four subjective (patient-reported) disease burden measures and 3 objective (anatomic and physiologic) disease burden measures were used for validation. Associations between composite indices or apnea-hypopnea index and these 7 construct validation measures were compared using bootstrapped correlation coefficients.', 'Two hundred sixteen subjects were included in the final analysis. Both composite disease burden indices showed clinically important or nearly important associations with 3 of 4 subjective validation measures and all 3 objective validation measures, whereas the apnea-hypopnea index was associated only with the objective validation measures.'] Do composite severity indices reflect sleep apnea disease burden more comprehensively than the apnea-hypopnea index?