Discussion
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This study evaluated the resource use and costs associated with an electronic clinical decision support system for AF patients in Nova Scotia, Canada. During the 12-month follow-up period, there were no statistically significant differences in costs or resource use between CDS and usual care groups. Nevertheless, the data obtained from this study provide important insight into the management of AF in a single payer system at the primary care level.Similar to other costing studies among the AF patient population, ER visits and hospitalizations comprised the expensive component of AF care [There are several reasons why patients’ costs may have been lower in the IMPACT-AF trial than other studies on the economic costs of AF. The first reason is that Nova Scotia has a public payer system in which the costs for hospitalizations, ER visits, family physicians, specialists, lab tests and, often, medications are covered by the province. This would reduce the cost burden for patients. A second reason is that participants in the study were being treated by primary health care professionals. Patients whose AF required management by specialists or a hospital-based AF clinic, with higher attendant costs, were excluded from the trial. A third reason why costs could have been lower in the IMPACT-AF trial is how they were measured. In the 12-month questionnaire and monthly diaries, participants were asked to report ‘AF-related’ costs and resource use. While some guidance was provided on potential reasons for AF-related ER visits (e.g., a racing heart), patients had to determine themselves if the visit was for their AF. A patient, for example, might see their physician for a reason other than AF, which could be opportunely addressed at the same visit. These patients might not see the association when filling out the study materials, which could result in underreporting of the costs or resource use associated with managing their AF. In addition, participants were instructed to only record certain costs in the diaries, such as the money spent for parking or on services received. The diaries did not include gas or meal expenses. As a result, the true costs that participants incurred due to their AF would have been higher as the data obtained from the diaries did indicate that some participants were driving long distances to receive AF care. The recently validated Cost for Patients Questionnaire identified a range of costs to be considered for patients, including travel costs, parking fees, prescription drugs, care services, medical devices, household renovations, medical tests, paramedical services, caregivers, accommodation for travel as well as costs associated with lost productivity [While out of pocket costs and time lost from work were minimal for most of the patients in our study, some reported driving long distances to receive care. Specifically, participants reported travelling a mean distance of 121 km for INR testing and 58 km for family physician visits. This speaks to the frequency of INR visits relative to other types of care evaluated as well as the accessibility of AF care in Nova Scotia. Fifty-four percent of participants in this study lived in a rural area, where access to labs and family physicians are limited. The fact that participants reported travelling the longest distance for INR testing is a consideration for why AF patients should receive a NOAC instead of warfarin as these medications don’t require lab monitoring. Much of the costs associated with warfarin monitoring is indirect; the province pays for the labs and tests, which are inexpensive at $3.85 per test. However, it is the patient who pays for the time, effort, and expense involved with getting to the lab appointments.Limitations of this study include the low percentage of patients who completed the diary and 12-month questionnaire. Case costing data sourced from administrative records provided the most accurate estimates of resource use and costs, but they were only available for central zone hospitals. Thus, apart from 75 patients (16.5%) who travelled from their residence in a rural location to a central zone hospital to receive care or received care at one of the rural facilities within the central zone, the case costing dataset excluded the majority of study participants from such districts (In addition to covering a limited group of participants, the case costing dataset provided information on ER visit and hospitalization costs only. To supplement this dataset, participants were asked to complete a monthly diary and 12-month questionnaire. The use of monthly diaries enabled a detailed record of the resources used and costs incurred from the patient perspective. Moreover, since monthly diaries collect information prospectively over a period of time, there is less recall error compared to a retrospective 12-month questionnaire [Another limitation of the study was the fact that only 3 in 4 providers in the CDS arm completed their training on how to use the CDS tool [