Design. This is a structured evidence-based review of all available studies on the relationship between chronic pain and sleep problems as defined by the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) category of sleep disorder due to a general medical condition.
Objectives. To determine whether chronic pain is etiologically associated with this sleep category.
Methods. Computer and manual literature searches yielded 146 references that addressed this area of study. One hundred and five studies were excluded from detailed review based on exclusion criteria detailed by this category of sleep disorders. Forty-one studies were reviewed in detail and sorted according to six natural groupings: multivariate analysis, prospective studies, path analysis, correlation between pain and sleep problems, univariate analysis using comparison groups, and do nonsedating drugs with analgesic properties improve sleep? Study characteristics were abstracted into tabular form and each report was characterized by the type of study it represented according to the Agency for Health Care Policy and Research (AHCPR) guidelines. Each study was independently evaluated by two raters according to 12 quality criteria and an independent quality score was calculated. Studies were not utilized in the calculations unless their quality score (utilizing both raters) was greater than 60%. For each of the above groupings, an average quality score was calculated and a calculation performed as to the percentage of studies that supported the hypothesis that pain is etiologically related to the above DSM-IV category of sleep disorders. Finally, the strength and consistency of the evidence for this hypothesis was rated according to the AHCPR guidelines.
Results. Of the 41 reports, all had quality scores greater than 60%. In all the above groupings except for multivariate analysis, 100% of the studies supported this hypothesis. In the multivariate analysis grouping, 77.2% of the studies supported this hypothesis. The strength and consistency of this evidence was rated at A (highest possible) for all study groupings except multivariate (B rating) and path analysis where there were too few studies to generate a conclusion. For all the studies combined, 89.7% of the studies supported this hypothesis. This evidence was rated as A: consistent, multiple studies.
Conclusions. The results of this evidence-based structured review indicate that for the pain–sleep studies defined by the DSM-IV category of sleep disorder due to a general medical condition,chronic pain may be etiologically related to that sleep problem. However, these results do not preclude this relationship from being bidirectional.