Statistical analysis
SECONDARY
Descriptive statistics were used to summarize the sociodemographic and clinical characteristics of patients. Since the distribution of the resource use and costing data is highly skewed, we present both medians and means. Costs were collected in 2017 Canadian dollars according to the timelines of the study and converted to 2021 dollars using the Canadian Consumer Price Index (CPI). All costs cover the 12-month period of participation in the study. The estimates obtained from the monthly diaries were summed across the 12 months to calculate a total per-patient estimate for the 12-month follow-up period.As cost and resource use were secondary outcomes of the IMPACT-AF trial, completion of the self-administered questionnaire and diaries was voluntary in nature and not a mandatory component of participation in the trial. As a result, some patients did not want to complete either but did provide consent for the study team to collect their healthcare data from medical records. This permitted the evaluation of the study’s primary outcome measure (presented in a previous manuscript). In total, 93 out of 1,145 participants (8%) chose this option (Given the amount and nature of missing data, results are reported as complete case analyses. When the proportion of missing data is substantial (greater than 40%), imputation may not provide an unbiased, reliable estimate [The IMPACT-AF trial was powered to detect a statistically significant difference in relative risk reduction for the study’s primary efficacy endpoint (a composite of unplanned cardiovascular hospitalizations and AF-related emergency department visits) and not to detect any meaningful differences in resource use or costs between study arms. As such, the analyses presented in this paper are considered pre-specified secondary endpoints [