Opioid use in chronic pain treatment is complex, as patients may derive both benefit and harm. Identification of individuals currently using opioids in a problematic way is important given the substantial recent increases in prescription rates and consequent increases in morbidity and mortality. The present review provides updated and expanded information regarding rates of problematic opioid use in chronic pain. Because previous reviews have indicated substantial variability in this literature, several steps were taken to enhance precision and utility. First, problematic use was coded using explicitly defined terms, referring to different patterns of use (ie, misuse, abuse, and addiction). Second, average prevalence rates were calculated and weighted by sample size and study quality. Third, the influence of differences in study methodology was examined. In total, data from 38 studies were included. Rates of problematic use were quite broad, ranging from <1% to 81% across studies. Across most calculations, rates of misuse averaged between 21% and 29% (range, 95% confidence interval [CI]: 13%-38%). Rates of addiction averaged between 8% and 12% (range, 95% CI: 3%-17%). Abuse was reported in only a single study. Only 1 difference emerged when study methods were examined, where rates of addiction were lower in studies that identified prevalence assessment as a primary, rather than secondary, objective. Although significant variability remains in this literature, this review provides guidance regarding possible average rates of opioid misuse and addiction and also highlights areas in need of further clarification.
aDepartment of Psychology, University of New Mexico, Albuquerque, NM, USA
bDepartment of Neurology, University of Washington, Seattle, WA, USA
cDepartment of Economics, University of New Mexico, Albuquerque, NM, USA
Corresponding author. Address: Department of Psychology, University of New Mexico, MSC03 2220, Logan Hall, 1 University of New Mexico, Albuquerque, NM 87131, USA. Tel: +1 505-277-4121; fax: +1 505-277-1394. E-mail address: firstname.lastname@example.org (K. E. Vowles).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received May 13, 2014
Received in revised form December 27, 2014
Accepted December 29, 2014