Abstract
Introduction
In individuals with chronic pain, sleep disturbances have been suggested to increase suffering, perception of pain, and to negatively affect long-term prognosis. This systematic review and meta-analysis aims to determine the pooled prevalence of sleep disturbances in chronic non-cancer pain patients with no other sleep disorders, using the patient-rated questionnaires Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI).
Methods
Multiple databases were searched for studies reporting the prevalence of sleep disturbances in chronic pain patients. Chronic pain was defined as pain >3 months. Comorbid sleep disorders such as sleep disordered breathing and restless leg syndrome were excluded. Sleep disturbances were defined using the PSQI cutoff of > 5 (poor sleep quality) and ISI ≥ 8 (subthreshold to clinical insomnia). The meta-analysis was conducted to examine the pooled prevalence of PSQI and ISI data using the inverse-variance random-effects model and to examine mean differences in PSQI scores.
Results
The systematic search resulted in 25,486 articles and 20 were included for analysis. In 12 studies using PSQI, the pooled prevalence of sleep disturbance was 75.3% among 3,597 chronic pain patients (mean age 53 ± 12 years; 74% female). In eight studies using ISI, the pooled prevalence was 72.9% among 2,578 chronic pain patients (mean age 63 ± 12 years; 57% female). The meta-analysis showed a significant mean difference of 2.75 (p < 0.001) in the global PSQI score between the chronic pain group versus the non-chronic pain group. The meta-analysis also showed a significant mean difference in the scores of four of seven PSQI components: sleep latency, sleep efficiency, sleep duration, and sleep disturbances (p < 0.05).
Conclusion
In chronic pain patients, the pooled prevalence of sleep disturbances as measured by PSQI (75.3%) and ISI (72.9%) studies was much higher than those reported for the general population. The relatively high prevalence of sleep disturbances in chronic pain patients emphasizes the importance of further characterizing the relationship between sleep and chronic pain.
Support (if any):
Oral controlled-release morphine sulfate. Analgesic efficacy and side effects of a 100-mg tablet in cancer pain patients