Theme: Epidemiology & Public Health Research Year: 2022
British Columbia, Canada’s westernmost province, consistently faces some of the highest rates of toxic
drug poisoning (i.e., overdose) deaths in the country. Previous research has shown that the rates increase
even further following income assistance payments, a phenomenon commonly known as the ‘cheque
week effect’. However, deaths capture only a small proportion of overdoses that take place in the
community. We examined the association between income assistance payment dates and emergency
department (ED) visits due to a suspected overdose within British Columbia’s largest regional health
We identified ED visits related to a suspected opioid-associated overdose between April 14, 2016 and
February 21, 2022 from hospital records. We compared daily overdose-related ED visits during cheque
weeks vs. non-cheque weeks using Welch’s t-test accounting for unequal variance. We examined whether
the COVID-19 pandemic magnified this effect, using negative binomial regression with the pandemic
period as an interaction term.
We calculated 20,024 overdose-related ED visits since an overdose public health emergency was declared
in April 2016. We identified a significant increase that started on cheque issuance day and lasted for five
days. The period around cheque issuance corresponded to a 39.5% increase in the daily average number
of visits, which translates to approximately 1,699 ‘excess’ overdoses. While the overall number of visits
increased during the COVID-19 pandemic, it did not correspond to a stronger cheque week effect
(interaction effect = 1.05; 95% CI 0.96-1.16).
The ‘cheque week effect’ contributed to a significant increase in the number of overdose-related ED visits,
and was observed consistently before and during the COVID-19 pandemic. Our findings suggest a need
for more equitable income options, enhanced harm reduction and social supports for people who use
drugs around cheque week, and further understanding of the needs of people with lived and living
Disclosure of Interest Statement:
No competing interest to disclose.