Journal Club Alcohol, Other Drugs, and Health: Current Evidence May-June 2007

Featured Article Persistent pain is associated with substance use after detoxification: a prospective cohort analysis Larson MJ, et al. Addiction. 2007;(Online Early Articles): doi: /j x.

Study Objective To examine whether persistent pain is associated with… an increased odds of substance use after detoxification

Study Design This was a secondary analysis of 397 subjects who had participated in a randomized clinical trial. All subjects had been admitted to an urban, residential drug and alcohol detoxification unit and interviewed periodically over 24 months. Researchers assessed pain with the SF-36 Health Survey and substance use with the Addiction Severity Index. Analyses were adjusted for potential confounders.

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

Are the Results Valid? Was the sample representative? Were the subjects sufficiently homogeneous with respect to prognostic risk? Was follow-up sufficiently complete? Were objective and unbiased outcome criteria used?

Was the sample representative? The sample was a cohort of adults admitted to an urban, residential alcohol and drug detoxification unit. –It is unclear how many were referred; 470 of 642 consented to enroll in the randomized trial. Because the primary study evaluated efforts to link patients to primary care after detoxification, patients who already had a primary care provider were excluded. –This somewhat limits the representativeness of the sample. Other important exclusions included being pregnant, not being able to list 3 contacts, and not providing consent.

Were the subjects sufficiently homogeneous with respect to prognostic risk?  All patients received standard detoxification services.  Randomization occurred after detoxification, indicating that the risk of relapse should have been similar in all subjects.  No information was provided on the distribution of pain disorders across the two study arms.

Was follow-up sufficiently complete? Subjects were assessed every 6 months over 24 months. 69% completed the 24-month interview.

Were objective and unbiased outcome criteria used? Self-reported outcomes (in the past 30 days) were assessed with the Addiction Severity Index and included... –Heavy alcohol use ( >3 drinks on at least 1 day or intoxication) –Cocaine use –Heroin/opioid use –Any substance use (i.e., heavy alcohol use or illicit use of cocaine or opioids) There was no mention of blinding to the primary independent variable of pain as assessed by the SF-36.

What are the Results? How likely are the outcomes over time? How precise are the estimates of likelihood?

How likely are the outcomes over time? Results (prospectively assessed): 16% reported persistent pain (moderate-to-higher pain levels at all available interviews) in the 24 months after detoxification. Subjects reporting persistent pain were more likely than those with mild or no pain to have (in the past 30 days at the 24-month follow-up)… –used any substance (odds ratio [OR], 4.21); –used heroin/opioids not prescribed for pain (OR, 5.36); –consumed >3 drinks on at least 1 day or been intoxicated (OR, 2.15); –used cocaine (OR, 2.05). All results, except for cocaine use, were significant.

How precise are the estimates of likelihood? Confidence Intervals [CI] are wide: –For any substance use: OR, 4.21; 95% CI, –For heroin/opioid use: OR, 5.36; 95% CI, –For heavy alcohol use: OR, 2.15; 95% CI, –For cocaine use: OR, 2.05; 95% CI,

How Can I Apply the Results to Patient Care? Were the study patients and their management similar to those in my practice? Was the follow-up sufficiently long? Can I use the results in the management of patients in my practice?

Were the study patients similar to those in my practice? Subjects are fairly representative of patients receiving residential detoxification. However, patients with existing primary care providers were excluded.

Was the follow-up sufficiently long? Follow-up occurred over 24 months. This timeframe is clinically important.

Can I use the results in the management of patients in my practice? These results should be primarily used to heighten clinicians’ concern about the risk of relapse to any substance–particularly opioids or alcohol–in their patients discharged from detoxification. Next steps should include exploring various strategies (nonopioid vs. opioid) for treating pain in patients with persistent complaints of pain after detoxification.