Association between mothers' postoperative opioid prescriptions and opioid-related events in their children: A population-based cohort study

Background: Postoperative opioid prescriptions may be associated with risks of unintentional poisoning and drug diversion in other household members. The objective of this study was to explore the association between mothers' postoperative opioid prescriptions and incidence of opioid-related events in their children (aged 1 to 24 years). Data and methods: This retrospective cohort study used individually linked administrative health data from Ontario, Canada. A population-based sample of 170,156 opioid-naive mothers (aged 15 to 64) (see Figure 1) who underwent surgery between 2013 and 2017 in Ontario was linked through birth records to create a cohort of their 283,550 opioid-naive children (aged 1 to 24). The association between postoperative opioid analgesic prescriptions filled by mothers within seven days of discharge after surgery and opioid-related events (emergency department presentations or inpatient admissions for opioid poisoning, or mental and behavioural disorders attributable to opioid use) in their children within one year of their mother's discharge was assessed. Results: Overall, 60.4% of the children in the cohort had a mother who filled a postoperative opioid prescription. The incidence of opioid-related events in children in the year after a mother's surgery was low overall (n=36/283,550, 0.01%), but higher among children whose mother filled a postoperative opioid prescription (n=29/171,139, 0.02%, vs. n=7/112,411, 0.01%, p=0.02), including in an analysis adjusting for child's age, mother's age, rural residence, neighbourhood income quintile and mother's Charlson comorbidity index score (adjusted odds ratio, 2.42 [95% confidence interval (CI), 1.05 to 5.54], p=0.04). Interpretation: Postoperative opioid prescriptions for mothers may contribute to opioid-related events in their children. These findings further underscore the importance of safe, effective opioid prescribing, as well as of patient and public education about the use, storage and disposal of these medications.