Journal Club Alcohol, Other Drugs, and Health: Current Evidence November-December 2007

Featured Article Risk factors for clinically recognized opioid abuse and dependence among veterans using opioids for chronic non-cancer pain Edlund MJ, et al. Pain. 2007;129(3):355–362.

Study Objective To identify… risk factors for diagnosed opioid abuse or dependence among chronic opioid users

Study Design Researchers analyzed demographic and clinical data from 15,160 veterans with… –chronic opioid use (>90 day prescription) for noncancer pain but –no diagnosis of an opioid use disorder (opioid abuse or dependence) in their medical records in 2000–2002. Researchers then compared veterans with a subsequent diagnosis of an opioid use disorder in 2003–2005 with veterans without this diagnosis in the same period.

Assessing Validity of an Article About Harm Are the results valid? What are the results? How can I apply the results to patient care?

Are the Results Valid? Did the investigators demonstrate similarity in all known determinants of outcomes? Did they adjust for differences in the analysis? Were exposed patients equally likely to be identified in the two groups? Were the outcomes measured in the same way in the groups being compared? Was follow-up sufficiently complete?

Did the investigators demonstrate similarity in all known determinants of outcomes? Did they adjust for differences in the analysis? All subjects were prescribed opioids. Factors known to be associated with developing prescription drug dependence (substance use disorders and psychiatric comorbidity) were controlled for in the mulitvariable analyses. Multivariable analyses did not adjust for the type of opioid (short vs. long-acting, weak vs. potent) that was prescribed.

Were exposed patients equally likely to be identified in the two groups?  All patients were prescribed opioids.

Were the outcomes measured in the same way in the groups being compared?  Passive surveillance was conducted for ICD-9 diagnoses of opioid abuse or dependence.  There was no attempt to systematically assess patients for opioid abuse or dependence.

Was follow-up sufficiently complete? Follow-up was obtained on all individuals in the cohort at 1–3 years. This may not be sufficient time for a diagnosis of opioid abuse or dependence to be recognized.

What are the Results? How strong is the association between exposure and outcomes? How precise is the estimate of the risk?

What are the Results? From to , 2% were diagnosed with opioid abuse or dependence. In adjusted analyses, veterans with the following in 2002 were more likely to have a subsequent opioid abuse or dependence diagnosis: –nonopioid substance use disorder (OR, 2.34) –mental health disorder (OR, 1.46) –greater number of outpatient healthcare visits (OR, 1.52 for 20+ visits versus 0–6 visits) –greater number of days supplied with opioids (OR, 1.84 for 211+ days versus 91–150 days)

How strong is the association between exposure and outcome? VariableAdjusted Odds Ratios and 95% Confidence Intervals Nonopioid abuse or dependence2.34 ( ) Mental health disorder1.46 ( ) Greater # of outpatient visits1.52 ( ) Greater # of days supplied with opioids 1.84 ( )

How precise is the estimate of the risk? The sample size is large. The confidence intervals are reasonable.

How Can I Apply the Results to Patient Care? Were the study patients similar to the patients in my practice? Was the duration of follow-up adequate? What was the magnitude of the risk? Should I attempt to stop the exposure?

Were the study patients similar to the patients in my practice? 95% were male. 80% were ≥50 years old. All were veterans. 71% were white. 54% had back pain. 45% had a mental health diagnosis. 47% received >211 days of opioids in the first treatment year.

Was the duration of follow-up adequate? No: –1–3 years is a short period of time for an individual’s opioid abuse or dependence to come to clinical recognition.

What was the magnitude of the risk? 2% (298 patients) of the sample had their chronic substance use disorder clinically recognized (diagnosis in medical record).

Should I attempt to stop the exposure? No information is presented on the benefit of the opioid therapy that was prescribed. According to this study, clinicians should assess the benefit of opioid therapy against the potential risk for opioid abuse and dependence… –especially in patients with prior diagnoses of substance use disorders, mental health disorders, high volume of clinic visits, and long-term opioid prescriptions.