1 in 4 Pain Patients Misuses Opioids

The rates of opioid misuse among US patients with chronic pain appear to average about 25%, according to the results of a recently published systematic review and data synthesis. The study, which appears in the April 2015 issue of Pain, also found that rates of opioid addition averaged about 10%.

“On average, misuse was documented in approximately one out of four or five patients and addiction in approximately one out of ten or eleven patients” who were prescribed opioids as part of their treatment for chronic pain, wrote Kevin E. Vowles, PhD, Associate Professor, Department of Psychology, University of New Mexico, and colleagues. The study investigators found a wide variation in reported rates of opioid misuse, abuse, and addiction across the 38 studies included in their review.

Noting that opioid use in chronic pain treatment is complex, given that patients may experience both benefits and harms, the research team sought to provide updated and expanded information regarding rates of problematic opioid use in chronic pain. They added that “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.”

For the study, Vowles and colleagues estimated the misuse and addiction rates by calculating data from the 38 reports. With previous reviews like theirs indicating substantial variability in these rates, they took several steps to enhance precision and utility.Adjustments were made based on study sample size, quality, and methods. Problematic use was coded using explicitly defined terms, referring to different patterns of use, such as misuse, abuse, and addiction.

Rates of problematic use varied quite widely, from less than 1% to 81% across the studies. The average rate of opioid misuse was estimated between 21% and 29% following adjusted analysis, with misuse defined as using opioids contrary to instructions, regardless of harmful or adverse effects. Estimated rates of opioid addiction—defined as continues opioid use with actual or potential harmful effects—averaged between 8% and 12% after adjustments.

Only one of the 38 studies reported on opioid abuse, defined as using the drugs for non-medical purposes. When study methods were examined, only one difference was found, in which rates of additions were lower in studies that identified prevalence assessment as a primary, as opposed to a secondary, objective.

Despite the significant variability evidenced among the review literature, Vowles and colleagues suggested that their review “provides guidance regarding possible average rates of opioid misuse and addiction and also highlights areas in need of further clarification.” In regard to opioid misuse, the study authors wrote “If it is accurate that approximately one in four patients on opioids display patterns of opioid misuse, but not addiction, then perhaps more efficient targeting of treatment resources would be of benefit. Some forms of misuse, for example, may be readily addressed through relatively low-intensity methods such as education or frequent follow-up visits.”

In light of their findings, the researchers noted that it is not clear whether the risks of opioid use outweigh the potential benefits. “We are not certain whether the benefits derived from opioids, which are rather unclear based on the extant literature, compensate for this additional burden to patients and health care systems,” they concluded.