Polysomnographic Predictors of Treatment Response to Cognitive Behavioral Therapy for Insomnia in Participants With Co-morbid Insomnia and Sleep Apnea: Secondary Analysis of a Randomized Controlled Trial.

Alexander Sweetman,Peter G Catcheside,Amanda O'Grady,Nick A Antic,Bastien Lechat,R Doug Mcevoy,Simon Smith,Nicola Dunn,Leon Lack

doi:10.3389/fpsyg.2021.676763

Abstract

ObjectiveCo-morbid insomnia and sleep apnea (COMISA) is a common and debilitating condition that is more difficult to treat compared to insomnia or sleep apnea-alone. Emerging evidence suggests that cognitive behavioral therapy for insomnia (CBTi) is effective in patients with COMISA, however, those with more severe sleep apnea and evidence of greater objective sleep disturbance may be less responsive to CBTi. Polysomnographic sleep study data has been used to predict treatment response to CBTi in patients with insomnia-alone, but not in patients with COMISA. We used randomized controlled trial data to investigate polysomnographic predictors of insomnia improvement following CBTi, versus control in participants with COMISA.MethodsOne hundred and forty five participants with insomnia (ICSD-3) and sleep apnea [apnea-hypopnea index (AHI) ≥ 15] were randomized to CBTi (n = 72) or no-treatment control (n = 73). Mixed models were used to investigate the effect of pre-treatment AHI, sleep duration, and other traditional (AASM sleep macrostructure), and novel [quantitative electroencephalography (qEEG)] polysomnographic predictors of between-group changes in Insomnia Severity Index (ISI) scores from pre-treatment to post-treatment.ResultsCompared to control, CBTi was associated with greater ISI improvement among participants with; higher AHI (interaction p = 0.011), less wake after sleep onset (interaction p = 0.045), and less N3 sleep (interaction p = 0.005). No quantitative electroencephalographic, or other traditional polysomnographic variables predicted between-group ISI change (all p > 0.09).DiscussionAmong participants with COMISA, higher OSA severity predicted a greater treatment-response to CBTi, versus control. People with COMISA should be treated with CBTi, which is effective even in the presence of severe OSA and objective sleep disturbance.

Highlights

Chronic insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders and frequently co-occur within the same patient (The American Academy of Sleep Medicine, 2014; Sweetman et al, 2017a)
It was hypothesized that participants with Co-morbid insomnia and sleep apnea (COMISA) who have more severe OSA and evidence of greater objective sleep disturbance may be less responsive to cognitive behavioral therapy for insomnia (CBTi), these data indicate that CBTi is an effective treatment among such participants
Emerging evidence suggests that CBTi may be an effective (Sweetman et al, 2019b; Alessi et al, 2020; Ong et al, 2020) and safe (Sweetman et al, 2020) overall treatment for COMISA, it is important to identify which patients are most responsive to CBTi, and which patients are less responsive to CBTi and require other initial treatments (e.g., Continuous positive airway pressure (CPAP))

Summary

Introduction

Chronic insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders and frequently co-occur within the same patient (The American Academy of Sleep Medicine, 2014; Sweetman et al, 2017a). Chronic insomnia is characterized by frequent difficulties initiating sleep, maintaining sleep, and/or early morning awakenings from sleep, and associated daytime functional impairments, which persist for at least 3 months (The American Academy of Sleep Medicine, 2014). OSA is characterized by frequent narrowing (hypopnea) or collapse (apnea) of the upper airway during sleep, resulting in reduced oxygen saturation, frequent cortical arousals, and daytime sleepiness and fatigue. The clinical index of OSA is the apneahypopnea index (AHI) which reflects the average number of respiratory events per hour of sleep. Moderate and severe OSA are commonly defined by an AHI of 15–29, and ≥30 events/h of sleep, respectively. Insomnia and OSA both increase risk of mental health problems (Peppard et al, 2006; Baglioni et al, 2011), and result in substantial societal costs through reduced productivity and quality of life, and high healthcare utilization (Ozminkowski et al, 2007; Wickwire et al, 2016; Natsky et al, 2020)

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