Association between discontinuing chronic opioid therapy and newly diagnosed substance use disorders, accidents, self-inflicted injuries and drug overdoses within the prescribers' health care system: a retrospective cohort study

Abstract

Background and aim: Prescribers are commonly confronted with discontinuing opioid therapy among patients prescribed chronic opioid therapy (COT). This study aimed to measure the association between discontinuing COT and diagnoses of substance use disorders (SUDs) and opioid-related adverse outcomes (AOs).

Design: Retrospective cohort study.

Setting: United States Veterans Healthcare Administration.

Participants: Veterans with chronic pain on COT who discontinued opioid therapy were compared with those continuing COT using data from fiscal years 2009 to 2015.

Measurements: Newly diagnosed substance use disorders (SUD composite; individual types: opioid, non-opioid drug and alcohol use disorders) and opioid-related adverse outcomes (AO composite; individual types: accidents resulting in wounds/injuries, opioid-related accidents/overdoses, alcohol and non-opioid medication-related accidents/overdoses, self-inflicted injuries and violence-related injuries) were evaluated. Primary analyses were conducted using 1:1 matching of discontinuers with those continuing COT based on propensity score and index date (±180-day window). Sensitivity analyses were conducted using logistic regressions with stabilized inverse probability of treatment weighting (SIPTW) and instrumental variable (IV) models.

Findings: A total of 15 695 (75.4%) and 17 337 (76.6%) discontinuers were matched with those continuing COT among the cohorts testing SUD and AO development respectively. In the primary propensity score matched analyses, the composite SUD outcome was not different between discontinuers and those continuing COT (OR = 0.932, 95% CI = 0.850, 1.022). The composite AO outcome was lower among discontinuers (OR = 0.660, 95% CI = 0.623, 0.699) compared with those continuing COT. SIPTW analyses found lower SUD (OR = 0.789, 95% CI = 0.743, 0.837), and AO (OR = 0.660, 95% CI = 0.623, 0.699) rates among discontinuers. IV models found mixed and sometimes contradictory results.

Conclusions: Discontinuing patients from chronic opioid therapy appears to be associated with decreased diagnoses for opioid-related adverse outcomes. The association with substance use disorders appears to be inconclusive.

Keywords: Chronic opioid therapy discontinuation; opioid overdose; opioid prescribing; opioid-related adverse outcomes; opioids; substance use disorders.