What percentage of chronic nonmalignant pain patients exposed to chronic opioid analgesic therapy develop abuse/addiction and/or aberrant drug-related behaviors? A structured evidence-based review.

DESIGN: This is a structured evidence-based review of all available studies on the development of abuse/addiction and aberrant drug-related behaviors (ADRBs) in chronic pain patients (CPPs) with nonmalignant pain on exposure to chronic opioid analgesic therapy (COAT).
OBJECTIVES: To determine what percentage of CPPs develop abuse/addiction and/or ADRBs on COAT exposure.
METHOD: Computer and manual literature searches yielded 79 references that addressed this area of study. Twelve of the studies were excluded from detailed review based on exclusion criteria important to this area. Sixty-seven studies were reviewed in detail and sorted according to whether they reported percentages of CPPs developing abuse/addiction or developing ADRBs, or percentages diagnosed with alcohol/illicit drug use as determined by urine toxicology. Study characteristics were abstracted into tabular form, and each report was characterized according to the type of study it represented based on the Agency for Health Care Policy and Research Guidelines. Each study was independently evaluated by two raters according to 12 quality criteria and a quality score calculated. Studies were not utilized in the calculations unless their quality score (utilizing both raters) was greater than 65%. Within each of the above study groupings, the total number of CPPs exposed to opioids on COAT treatment was calculated. Similarly, the total number of CPPs in each grouping demonstrating abuse/addiction, ADRBs, or alcohol/illicit drug use was also calculated. Finally, a percentage for each of these behaviors was calculated in each grouping, utilizing the total number of CPPs exposed to opioids in each grouping.
RESULTS: All 67 reports had quality scores greater than 65%. For the abuse/addiction grouping there were 24 studies with 2,507 CPPs exposed for a calculated abuse/addiction rate of 3.27%. Within this grouping for those studies that had preselected CPPs for COAT exposure for no previous or current history of abuse/addiction, the percentage of abuse/addiction was calculated at 0.19%. For the ADRB grouping, there were 17 studies with 2,466 CPPs exposed and a calculated ADRB rate of 11.5%. Within this grouping for preselected CPPs (as above), the percentage of ADRBs was calculated at 0.59%. In the urine toxicology grouping, there were five studies (15,442 CPPs exposed). Here, 20.4% of the CPPs had no prescribed opioid in urine and/or a nonprescribed opioid in urine. For five studies (1,965 CPPs exposed), illicit drugs were found in 14.5%.
CONCLUSION: The results of this evidence-based structured review indicate that COAT exposure will lead to abuse/addiction in a small percentage of CPPs, but a larger percentage will demonstrate ADRBs and illicit drug use. These percentages appear to be much less if CPPs are preselected for the absence of a current or past history of alcohol/illicit drug use or abuse/addiction.