Objectives: Chronic pain, with or without an identified diagnosis or cause, is widespread and commonly associated with sleep disturbances. However, research has often used poor quality measures of sleep and focused on specific pain conditions, thereby limiting its reliability and applicability to the wider CP population. This study meta-analysed the findings from studies that used objective polysomnographic measures of sleep or examined diagnosed sleep disorders in people with CP.
Methods: Three databases were searched (PubMed, PsychINFO, Embase; inception to June 2017) for case-controlled polysomnography studies and studies that reported the prevalence of diagnosed sleep disorders in adults with CP. Hedge's g effect sizes and prevalence rates were calculated using the data from 37 studies.
Results: Polysomnographic measures of sleep onset latency and efficiency, time awake after sleep onset and awakenings were all significantly worse in those with CP when compared to healthy controls (large effects). Total sleep time, light sleep duration (NREM 1), number of stage-shifts, respiratory-related events and periodic limb-movements were also worse for those with CP, albeit to a lesser extent (small to medium effects). The pooled prevalence of sleep disorders in CP was 44%, with insomnia (72%), restless legs syndrome (32%) and obstructive sleep apnea (32%) being the most common diagnoses.
Conclusions: Objective polysomnographic measures indicate that individuals with CP experience significant sleep disturbances, particularly with respect to sleep initiation and maintenance. Clinically diagnosed sleep disorders are also very prevalent. It is imperative that sleep disturbances and disorders be assessed and treated in conjunction with the CP.
Keywords: Chronic pain; Polysomnography; Sleep disorders; Sleep disturbance.
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