Long-Term Oral Anticoagulant Management Associated with Routine Medical Care (RMC) In Patients with Non-Valvular Atrial Fibrillation (NVAF) In Canada,

There are no prospective, long-term studies describing the process and quality of care, resource utilization (RU), and quality of life (QoL) associated with being on oral anticoagulant therapy for non-valvular atrial fibrillation (NVAF) patients managed through routine medical care (RMC) in Canada.

Resource utilization associated with Oral Anticoagulant Management (ROAM) is a prospective cohort study being conducted across 9 Canadian provinces whose objective is to describe the process and quality of care, RU, clinical events and health utility scores associated with long-term oral anticoagulant (warfarin) therapy in patients with new onset or chronic NVAF. Eligible, consenting patients are followed for 48 weeks and complete a weekly study diary providing data on international normalized ratio (INR) test dates and values, RU associated with warfarin monitoring, and all physician visits, procedures and hospitalizations. Health utility scores, representing the patient's health state, measured using the EuroQol-5D (EQ-5D) standardized QoL instrument are collected every 4 weeks. INR test values and dates and source documentation around patient reported clinical events are also collected from the participating physicians.

497 out of a planned enrolment of 600 patients have been recruited. 180 patients with completed 48 week follow-up and physician-provided INR values are included in this analysis, 98% from primary care physicians and specialists (RMC) and 2% from anticoagulant clinics. Median age [range] was 75 [39, 90] years with 67% males. Common co-morbidities were hypertension (60%) and ischemic heart disease (27%). Estimated median [range] time since NVAF diagnosis was 4 [0, 32] years. Physicians reported a total of 2484 INR tests over the study duration (a mean of 13.8 tests per patient) while patients recorded 2711 tests being completed in their diaries over the same time period (a mean of 15.06 tests per patient). Of the 2711 patient reported tests only 1914 INR results (71%) were communicated back to patients via telephone (70%) or in person (15%). Median [quartile] time between the INR test and the patient acquiring the results was 1.4 [1.0, 2.5] days. The INR test dates provided by physicians matched the dates recorded by patients in the diary 67% of the time. 51 (28%) of patients recorded no INR values. Of the 129 patients with at least one recorded INR value, physician and patient INR values matched completely for only 8 (4%) patients and matched on average 62% of the time (range 30% to 98%) for the rest. Mean [95% CI] time in therapeutic range (TTR) by the Rosendaal method was 67% [64%, 71%] using physician reported values and 67% [62%, 72%] based on patient reported values. Mean INR testing frequency was 30 days following an INR in the therapeutic range, 25 days following an INR of less than 2 and 22 days following an INR greater than 3. Three strokes and 3 bleeds were self-reported in 5 patients (9%) that are being adjudicated. The initial mean [95% CI] health utility score was 0.85 [0.83, 0.88]. A decrease in health utility score was observed in 133 (74%) of the patients based on a random effects regression model. Fixed effect estimate of the mean [95% CI] change in health utility scores per 6 months was −0.01 [0, −0.02]. Covariates (age, gender and time since diagnosis) were investigated but had limited effect on the health utility score.

This is the first prospective cohort study of NVAF patients on long-term warfarin therapy being monitored primarily through RMC in Canada. The majority of patients are monitored via telephone with frequent miscommunication between health care providers and patients about INR results and delays in getting results to patients. TTR is higher than previously reported for RMC, which may suggest a self-selection bias for better quality physician-patient combinations. Although frequency of testing was appropriate for in-range INRs, the times to testing after out-of-range results appear delayed. Analysis of health utility scores showed a small decrease in health status over time in this cohort of patients with generally high health utility scores. Relationship between TTR and clinical events will be presented.

Selby:Boehringer Ingelheim: Honoraria, Research Funding. Mittmann:Boehringer Ingelheim: Research Funding. Isogai:Boehringer Ingelheim: Research Funding. Kaus:Boehringer Ingelheim: Research Funding. Koo:Boehringer Ingelheim: Research Funding. Sealey:Boehringer Ingelheim: Research Funding.