Systematic review of prevalence, correlates, and treatment outcomes for chronic non-cancer pain in patients with comorbid substance use disorder.

Recent data suggest that comorbid substance use disorders (SUDs) are common among chronic non-cancer pain (CNCP) patients; however, prevalence rates vary across studies and findings are limited regarding treatment options for CNCP patients with comorbid SUD. The purpose of this systematic review is to assess the prevalence, associated demographic and clinical characteristics, and treatment outcomes for CNCP patients with comorbid SUD. We conducted searches from Ovid MEDLINE, PsychINFO, and PubMED from 1950 through February 2010 and retrieved the references. Thirty-eight studies met inclusion criteria and provided data that addressed our key questions. Three to forty-eight percent of CNCP patients have a current SUD. There are no demographic or clinical factors that consistently differentiate CNCP patients with comorbid SUD from patients without SUD, though SUD patients appear to be at greater risk for aberrant medication-related behaviors. CNCP patients with SUD are more likely to be prescribed opioid medications and at higher doses than CNCP patients without a history of SUD. CNCP patients with comorbid SUD do not significantly differ in their responses to treatment compared to CNCP patients without SUD, though the quality of this evidence is low. Limited data are available to identify predictors of treatment outcome. Although clinical experience and research suggests that SUDs are common among CNCP patients, only limited data are available to guide clinicians who treat this population. Research is needed to increase understanding of the prevalence, correlates, and responses to treatment of CNCP patients with comorbid SUDs.