Major Clinical Events in Patients Who Switched From Warfarin to DOACs: A Real-World Study Based on National Claims Data From the Contributory Regime in Colombia

OBJECTIVES: To evaluate the benefits of DOACs in individuals with NVAF who switched (switchers) compared to those who remained (non-switchers) in warfarin.

METHODS: Using patient-level data from national claim databases, we identified all individuals who received a first diagnosis of NVAF at any time from 2014 to 2019. All individuals with at least one warfarin prescription around the first 6 months of the diagnosis of NVAF and at least six-monthly warfarin prescriptions within the first year after the diagnosis of NVAF were considered eligible. All individuals who stopped warfarin at least 12 months before the end of follow-up were considered as switchers. The effects of switching on the rate of major vascular events were evaluated using a Poisson Regression Analysis, and are shown using unadjusted 5-year incidence rates per 1,000 patient-years and Adjusted Incidence Rate Ratios (aIRR) with their corresponding 95% Confidence Intervals (95% CI).

RESULTS: We identified 1,689 switchers (mean age=74.4 years, SD=9.6) and 927 non-switchers (mean age=74.5 years, SD=10.7). Switchers were followed for a mean of 659 days (SD=404) in warfarin, and for a mean of 683 days (SD=348) in DOACs. Non-switchers were followed for a mean of 1,088 days (SD=503). Unadjusted event rates for switchers and non-switchers were the following: death, 25.1 vs 69 (aIRR 0.24, 95% CI 0.19 to 0.31); ischaemic stroke, 142.5 vs 225.3 (aIRR 0.68, 95% CI 0.6 to 0.76); major bleeding,17.4 vs 38.3 (aIRR 0.49, 95% CI 0.36 to 0.67); and haemorrhagic stroke 1.1 vs 0.8 (aIRR 2.2, 95% CI 0.35 to 13.67).

CONCLUSIONS: This real-world study suggests that switching to DOACs may be associated with decreasing rates of major clinical events in patients with NVAF. We believe that these differences might be even greater given the substantial number of individuals who did not fulfil eligibility criteria due to suspected low adherence to warfarin treatment.