Physicians Often Can't Predict Who Will Misuse Pain Meds

Allison Gandey

May 27, 2011 (Austin, Texas) — Prescribers trying to determine who will abuse pain medications are wrong about half the time, a new study shows.

Presenting here at the American Pain Society 30th Annual Scientific Meeting, researchers found that the ability of physicians to correctly predict at-risk patients was only slightly better than chance.

Investigators in this industry-funded study looked at 549 patients from 50 practices. Clinicians were asked to identify which patients they thought were at risk for medication misuse and those who weren't, using standard risk assessment methods.

Researchers then compared these results to urine drug tests. Physicians' best guesses were most accurate for patients they believed to be misusing their medications. However, in the group thought to be compliant, clinicians missed 60% of patients who went on to have an abnormal urine drug test.

Misuse was confirmed if illicit drugs were present or if prescribed medications were absent in the urine sample.

Table 1. Risk Assessments of Patients Receiving Long-Term Opioid Therapy

Investigators included a third random group in which no physician risk assessments were performed (n = 172). Most of these patients, 61%, had a normal test result; however, 30% were misusing drugs.

The team led by Harry Leider, MD, chief medical officer at Ameritox, a company that provides pain medication monitoring, concludes that all patients receiving long-term opioid therapy should have urine drug testing to identify those who may be misusing their medications.

The current 2009 American Pain Society guidelines call for urine analysis, but not in all cases.

One Center's Experience

In a separate presentation at the meeting, researchers described the experience of an internal medicine practice.

Shahid Rafique, MD, from the New Snellville Clinic in Georgia, explained that he started urine drug monitoring in all patients receiving chronic pain and psychotropic medications.

"For clinicians not primarily focused on pain patients, performing urine drug testing in a small number of patients may not be a priority, however, with increasing drug abuse and misuse, it seems imperative all physicians prescribing controlled substances monitor patients receiving these medications," he noted in the presentation he coauthored with Kathryn Bronstein, director of medical science and health outcomes research at Ameritox.

Dr. Rafique assessed risk on the basis of medical and social history, requests for early refills, or the need for escalating doses to control pain. He then compared these predictions to the results of urine drug testing.

So far, 41 patients in Dr. Rafique's clinic have been tested. Results were normal in only 17 patients.

Table 2. Urine Drug Test Results

When comparing these test results with prior assessments, investigators found about half of patients (12 of 26) were not considered at risk.

In those thought to be in danger of misusing their prescription, close to 80% did go on to have an abnormal urine drug test result (11 of 14).

"These results, while from a single practice," the authors conclude, "illustrate the need for urine drug testing in all patients on chronic controlled medications. Even clinicians who have only a limited number of chronic pain patients need to monitor medication adherence."

False-Positive and -Negative Results

Asked by Medscape Medical News to comment on these findings, Mark Sullivan, MD, from the University of Washington in Seattle, cautioned that there is more to drug monitoring than urine testing.

"Urine analysis is not the 'be all, end all' of monitoring," he said. "There is a whole set of best practices of which this is one component."

Urine analysis is not the 'be all, end all' of monitoring.

Dr. Sullivan pointed to the many limitations of urine drug testing, including the high incidence of false-positive and -negative results. "Testing can be difficult to implement, hard to interpret, and expensive to confirm," he said. "Companies need to be transparent about the sensitivity and specificity and what we can anticipate with these tests."

Dr. Sullivan recommends that clinicians order a urine drug test when patients start therapy and again if still receiving treatment 90 days later. "Younger patients tend to be more at risk, [along with] people with a history of mental health problems or substance abuse."

In the US Food and Drug Administration's long-awaited opioid plan unveiled last month, regulators opted to focus on new education programs for prescribers. The opioid Risk Evaluation and Mitigation Strategy (REMS) will require drug makers to provide and pay for the plan, although the training is not mandatory for prescribers.

These studies were funded by Ameritox, a company that provides pain medication monitoring services. Some of the authors are company employees.

American Pain Society (APS) 30th Annual Scientific Meeting: Posters 111 and 119. Presented May 19, 2011.