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Project methods

This project is establishing a surveillance system on opioid-related harms among Ontario workers by expanding and adapting an existing surveillance system called the Occupational Disease Surveillance System (ODSS).  

What is the Occupational Disease Surveillance System (ODSS)?  

The ODSS, based at the Occupational Cancer Research Centre at Ontario Health, identifies risks of occupational disease in the Ontario workforce. In Ontario, administrative health data (e.g., data on hospitalizations, emergency room visits, outpatient visits) generally do not include information about patients’ employment or work history. The ODSS was developed in 2014 to address this gap, by linking existing administrative health data to occupational data, and has since been used to detect risks of cancers and other health outcomes in over 800 occupations and industry groups.  

You can learn more about the ODSS and its previous findings by disease and by sector. 

What data from the ODSS will be used in this project?  

The Opioid-Related Harms among Ontario Workers project uses the occupational and health data of 1.7 million workers in the ODSS. These data allow us to examine the incidence and trends of opioid-related harms within different occupations and industry groups. 

The databases linked in the ODSS and used for the surveillance of opioid-related harms include: 

  • Workplace Safety and Insurance Board (WSIB) accepted lost-time compensation claim records, containing employment information on workers in Ontario who experienced work-related injuries and illnesses from 1983-2019¬†
  • Registered Persons Database (RPDB), containing demographic information for all Ontarians registered for provincial health insurance from 1990-2020¬†
  • Discharge Abstract Database (DAD), containing information on inpatient hospitalizations from 2006-2020¬†
  • National Ambulatory Care Reporting System (NACRS), containing information on emergency department visits from 2006-2020¬†

As part of this project, the ODSS will be updated on an ongoing basis. In future, WSIB lost-time claim records up to December 31, 2021 and health data up to March 2022 will be added. 

What opioid-related harms are captured by the ODSS? 

This project is capturing information on hospitalizations and emergency department visits for three opioid-related harms: 

  • poisonings (or overdoses)‚ÄĒtoxicity due to an excess of opioids in one‚Äôs body; occurs when opioids (pharmaceutical, non-pharmaceutical or a combination of both) are taken incorrectly, whether accidentally or intentionally¬†
  • mental and behavioural disorders‚ÄĒmental health and behavioural disorders of varying severity and clinical forms (e.g., dependence, states of withdrawal or intoxication) that can be attributed to the use of opioids, whether prescribed or not¬†
  • adverse drug reactions‚ÄĒharmful or unpleasant effects caused by prescribed opioids that have been taken or administered as prescribed ¬†¬†

Each type of harm is identified in the DAD (hospitalization data) and NACRS (emergency department data) using diagnostic codes set out in the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Canada (ICD-10-CA). 

For more details on the methods used to identify each type of harm, please refer to Case Definitions for Opioid-Related Harms (PDF, 181KB).

What worker characteristics are included in the ODSS? 

This project is exploring how certain factors may be related to worker experiences of opioid-related harms. Specifically, the project is looking at ODSS information on workers: 

  • age and sex¬†
  • place of residence (specifically, the public health unit in which they reside)¬†
  • occupation at the time of claim, coded according to the 1971 Canadian Classification Dictionary of Occupations (CCDO), which includes 22 divisions, 88 major groups and 487 minor groups¬†
  • industry or sector at the time of claim, coded according to the Standard Industry Classification 1970 (SIC-70) and 1980 (SIC-80), which includes 10 divisions, 49 major groups, and 248 minor groups.¬†

What analyses is the project team doing? 

Using the new data in the updated ODSS, the project team is conducting the following analyses:  

  • descriptive analyses to estimate trends in the annual incidence rate of opioid-related harms over time since 2006, overall and according to demographic, injury and employment characteristics of workers¬†
  • comparison of incidence rates of opioid-related harms in the ODSS cohort to those in the general Ontario population since 2006, overall and according to demographic, injury and employment characteristics of workers¬†
  • Cox proportional hazards regression modelling to estimate associations between demographic and occupational characteristics, and the incidence rate of single and recurrent episodes of opioid-related harms¬†