Surveillance for Opioid-Associated Amnestic Syndrome in Canada, 2010-2022

Objectives A single diagnostic code could be used to perform surveillance for opioid-associated amnestic syndrome (OAS) in healthcare datasets on a national scale. Methods A request was submitted to search the Discharge Abstract Database (DAD) and the National Ambulatory Care Reporting System (NACRS) in Canada for the ICD-10-CA code, F11.6 (mental and behavioural disorders due to use of opioids, amnesic syndrome) during fiscal years (FY) 2010-2011 through 2022-2023. The annual total of encounters using this code was determined and crude rates per million were calculated for the Canadian population represented. Results National counts from DAD and NACRS combined ranged from <5 to 14 annually. Rates per million for available years fell between 0.17 and 0.48. For available data through FY 2015-2016, the mean number of annual combined encounters nationally was 6.3; for those years after, the mean was 10. The mean rate per million was 0.23 and 0.35 for these two periods, respectively. Discussion This study represents the first effort to conduct surveillance for OAS on a national scale and suggests that the condition is relatively rare. Future efforts to validate the coded diagnosis of OAS with confirmed cases will help determine its value as a surveillance tool.