Age differences in work-disability duration across Canada: examining variations by follow-up time and context

Purpose This study aimed to understand age differences in wage-replacement duration by focusing on variations in the relationship across different periods of follow-up time. Methods We used administrative claims data provided by six workers' compensation systems in Canada. Included were time-loss claims for workers aged 15-80 years with a work-related injury/illness during the 2011 to 2015 period (N = 751,679 claims). Data were coded for comparability across cohorts. Survival analysis examined age-related differences in the hazard of transitioning off (versus remaining on) disability benefits, allowing for relaxed proportionality constraints on the hazard rates over time. Differences were examined on the absolute (hazard difference) and relative (hazard ratios [HR]) scales. Results Older age groups had a lower likelihood of transitioning off wage-replacement benefits compared to younger age groups in the overall models (e.g., 55-64 vs. 15-24 years: HR 0.62). However, absolute and relative differences in age-specific hazard rates varied as a function of follow-up time. The greatest age-related differences were observed at earlier event times and were attenuated towards a null difference across later follow-up event times. Conclusions Our study provides new insight into the workplace injury/illness claim and recovery processes and suggests that older age is not always strongly associated with worse disability duration outcomes. The use of data from multiple jurisdictions lends external validity to our findings and demonstrates the utility of using cross-jurisdictional data extracts. Future work should examine the social and contextual determinants that operate during various recovery phases, and how these factors interact with age.