Underreporting of adverse events to health authorities by healthcare professionals: a red flag-raising descriptive study.

Background: An adverse event (AE) is any undesirable medical manifestation in an individual who has received pharmacological treatment. To be considered serious (SAE), it needs to meet minimally one of the severity criteria by Health Canada. The most recent data (2006) suggested that AEs were underreported (<6%) to health authorities. In Canada, since the implementation of Vanessa's Law (2019), hospitals are required to report SAEs, however this law remains relatively unknown.. The objectives of the study were: 1) to document the incidence of any adverse event (AE) and serious adverse event (SAE) over time in a "real" clinical context, 2) to quantify SAEs reported to Health Canada, and 3) to assess whether Vanessa's Law has led to an increase in mandatory reporting to Health Canada.

Method: We carried out a descriptive retrospective study at the Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, including 500 patients hospitalized between 2018/01/01 and 2021/12/31 and randomized into 4 cohorts (125 patients/year). Descriptive and comparative analyses were performed.

Results: The characteristics of the cohorts were: 43.6% women; median age: 69 years [min-max: 21-96 years], number of comorbidities: 4 [1-12]. During their hospitalization, patients consumed 18 different drug products [2-56] and the median of observed SAEs/patients was 0 [0-10] (total: 302). The overall percentage of SAEs reported to Health Canada was 0%, before and following the implementation of Vanessa's Law.

Conclusion: According to 500 electronic medical records, SAEs were underreported to Health Canada, even after the implementation of Vanessa's law.