Insomnia subtypes in sleep apnea: implications for screening and treatment

Abstract

Introduction Screening of obstructive sleep apnea in primary care settings is challenging for the family doctor, given the wide variety of patients’ symptom complaints. We developed the Sleep Symptoms Checklist (SSC), which groups common complaints into four subscales: Insomnia, Daytime Distress, Sleep Disorder, and Psychological Distress. In the present study, we investigated whether different SSC profiles exist for sleep apnea and chronic insomnia, in patients with and without an insomnia complaint. Materials and methods Participants were 88 primary care patients with OSA; 57 individuals, without OSA, who sought cognitive- behaviour therapy for insomnia (CBT-I); and 14 healthy community controls without sleep apnea or sleep complaints. All completed the SSC and a sleep questionnaire. Sleep apnea participants were segregated into three groups according to their sleep questionnaire responses: no insomnia (OSA), n = 21; insomnia including a complaint and objective poor sleep (OSA-I), n = 30; and insomnia by objective criteria but no complaint (OSA-I-NC), n = 37. Results There was no statistical difference in the severity of sleep apnea for the 3 OSA groups. All five groups were compared using ANOVA on the SSC subscale scores. The 3 OSA groups were characterized by worse Sleep Disorder scores than the CBT-I and Control groups. The two OSA groups with insomnia had worse Insomnia scores than the OSA and Control groups. The CBT-I participants had significantly worse Insomnia and Psychological Distress scores than the other clinical groups and their Sleep Disorder scores were similar to those of the Control group. Psychological Distress was worse for groups with insomnia (OSA-I- NC, OSA-I, CBT-I) compared to the OSA and Control groups. Conclusion The present study demonstrates that the SSC can be used to identify distinct clinical “profiles” for sleep apnea patients with and without the complaint of insomnia and for chronic insomnia patients with without sleep apnea. Of particular clinical importance is the identification of two subgroups of sleep apnea patients – those who have diagnosable insomnia and those who meet objective criteria for insomnia but are uncomplaining. The sleep problems of the non-complaining group of apnea patients with insomnia may not come to the attention of their treating sleep doctor and yet may interfere with CPAP therapy acceptance and adherence. These profiles help identify sleep apnea patients who could benefit from additional treatment for insomnia. Acknowledgement This research was supported by the Canadian Institutes of Health Research.