Persistent pain is associated with substance use after detoxification: a prospective cohort analysis.

AIMS: To test the hypothesis that persistent pain is associated with an increased odds of substance use after detoxification.

DESIGN: Analysis of data from a prospective cohort enrolled in a randomized controlled trial (RCT) to improve linkage with primary medical care.

SETTING: An urban residential detoxification program.

PARTICIPANTS: Adults (n = 397) enrolled in the RCT with heroin, alcohol or cocaine as a substance of choice and at least one follow-up interview.

MEASUREMENTS: The key independent variable was pain status: persistent pain (moderate to very severe pain at all available interviews), no pain (mild pain or less at all available interviews) and intermittent pain (all others). There were four outcomes of interest: self-reported use of any substance; heroin/opioid use; heavy alcohol use; and cocaine use 24 months after detoxification. Multivariable logistic regression controlled for several covariates including demographics, physical/sexual abuse, depressive symptoms, duration of follow-up and addiction severity at study entry.

FINDINGS: Pain in detoxification patients was common; 16% had persistent pain and 54% had intermittent pain. Persistent pain was associated with an increased odds for use of any substance [adjusted odds ratio (AOR) 4.2, 95% confidence interval (CI) 1.9-9.3], heroin/opioid use (AOR 5.4, 95% CI 2.1-13.8) and heavy alcohol use (AOR 2.2, 95% CI 1.0-4.5) at the 24-month follow-up. A statistically non-significant increase in the odds of cocaine use (AOR 2.0, 95% CI 0.9-4.6) was also observed.

CONCLUSIONS: Among individuals leaving residential detoxification, chronic pain is a common problem and is associated independently with long-term substance use after detoxification. Addressing pain as a treatable chronic condition among adults receiving detoxification presents a potential opportunity to improve long-term clinical outcomes and warrants further intervention research.