Clinical Characteristics in Two Subgroups of Obstructive Sleep Apnea Syndrome in the Elderly: Comparison Between Cases With Elderly and Middle-Age Onset

Abstract

Morbidity due to obstructive sleep apnea syndrome (OSAS) is increased in the elderly population. However, the clinical characteristics of OSAS in elderly patients have not been characterized conclusively. The aim of this study was to clarify differences in clinical characteristics of OSAS between patients with middle-age onset and elderly onset of OSAS. Patients with OSAS aged > or = 65 years were classified into groups according to age at first identification of respiratory pauses during sleep: a middle-age onset group (n = 32) where onset was at age < 50 years and an elderly onset group (n = 31) where onset was at age > or = 60 years. We compared demographic variables; polysomnographic variables; daytime sleepiness measures, including the multiple sleep latency test (MSLT) and the Epworth sleepiness scale (ESS); and adequate level of nasal continuous positive airway pressure (CPAP) between groups. BMI and frequency of underlying cardiovascular disorder were lower in the elderly onset group than in the middle-age onset group. No significant differences in apnea-hypopnea index or percentage of the period showing O(2) desaturation were seen between groups. However, arousal index, maximal negative esophageal pressure value, and adequate nasal CPAP level were significantly smaller in the elderly onset group. Mean sleep latency on MSLT was longer, and ESS score was lower in the elderly onset group. Compared with the middle-age onset group, the clinical significance of OSAS in the elderly onset group seemed to remain milder. This finding is possibly because of the smaller physiologic response to respiratory events.