Doctor shopping among chronic noncancer pain patients treated with opioids in the province of Quebec (Canada): incidence, risk factors, and association with the occurrence of opioid overdoses

INTRODUCTION: Prescription opioids continue to be involved in the opioid crisis, and a better understanding of factors associated with problematic opioid use is needed. OBJECTIVES: The aim of this study was to assess the incidence of opioid doctor shopping, a proxy for problematic opioid use, to identify associated risk factors, and to assess its association with the occurrence of opioid overdoses. METHODS: This was a retrospective cohort study of people living with chronic noncancer pain (CNCP) and treated with opioids for at least 6 months between 2006 and 2017 in the province of Quebec (Canada). Data were drawn from the Quebec health administrative databases. Doctor shopping was defined as overlapping prescriptions written by ≥ 2 prescribers and filled in ≥3 pharmacies. RESULTS: A total of 8,398 persons with CNCP were included. The median age was 68.0 (Q1: 54; Q3: 82) years, and 37.1% were male. The 1-year incidence of opioid doctor shopping was 7.8%, 95% confidence interval (CI): 7.2–8.5. Doctor shopping was associated with younger age (hazard ratio [HR] 18–44 vs ≥65 years: 2.22, 95% CI: 1.77–2.79; HR 45–64 vs ≥65 years: 1.34, 95% CI: 1.11–1.63), male sex (HR = 1.20, 95% CI: 1.01–1.43), history of substance use disorder (HR = 1.32, 95% CI: 1.01–1.72), and anxiety (HR = 1.41, 95% CI: 1.13–1.77). People who exhibited doctor shopping were 5 times more likely to experience opioid overdoses (HR = 5.25, 95% CI: 1.44–19.13). CONCLUSION: Opioid doctor shopping is a marginal phenomenon among people with CNCP, but which is associated with the occurrence of opioid overdoses. Better monitoring of persons at high risk to develop doctor shopping could help prevent opioid overdoses.