ABC | Volume 114, Nº3, March 2020

Original Article Silva et al. Warfarin therapy in NVAF patients in Brazil Arq Bras Cardiol. 2020; 114(3):457-466 all-cause costs incurred by each patient, disregarding the reason for the utilization, consequently, they could have been overestimated. Healthcare resource utilization and patient subgroups were not evaluated. According to Brazilian standards for procedure codes (Appendix A), INR has no individual code, but it is included within the “Coagulation test” code. As it was not possible to segregate, the INR measurement was considered as the entire coagulation test, and not as a percentage of it, for all patients. It was found that a significant portion of patients taking warfarin (11%) had CHA 2 DS 2 -VAS C scores of zero, which is greater than the proportion reported in other studies (6.1%). 36 CHA 2 DS 2 -VAS C assessment is subject to the clinical documentation of patients’ clinical history, and details of pre‑existing conditions might have been underreported. The phone monitoring program was offered to patients of a specific health insurance company and when a patient’s contract terminated, follow-up was not possible. Finally, some of the study limitations were inherent to a retrospective observational study design. These include potential coding errors and missing data which may have introduced biases into the study and affected the number of excluded patients, and the fact that the data assessed was not originally collected for clinical research purposes. Conclusions This study examined patient profiles, quality of anticoagulation and clinical/economic outcomes among NVAF warfarin patients in a private health insurance company in Brazil. It is representative of a large and relatively young cohort of warfarin patients. The overall quality of anticoagulation management was suboptimal. Warfarin patients were within the therapeutic range slightly more than half of the time. Up to two thirds had poor control (TTR < 65%) and were associated with more bleeding events and costs. This analysis highlights the importance, in terms of outcomes and costs, of tight anticoagulation control for NVAF patients treated with warfarin, and the difficulty in maintaining an adequate TTR even with a well-designed and run program. Additional research is needed, as more real-world data becomes available, to further assess the use of warfarin as well as the adoption of NOACs versus warfarin. Author contributions Conception and design of the research and Analysis and interpretation of the data: Silva PGMB, Sznejder H, Vasconcellos R, Charles GM, Mendonca-FilhoHTF, Mardekian J, Nascimento R, Dukacz S, Di Fusco M; Acquisition of data: Sznejder H; Statistical analysis: Mardekian J, Di Fusco M; Obtaining financing: Silva PGMB, Sznejder H, Vasconcellos R, Charles GM, Mendonca-Filho HTF, Di Fusco M; Writing of the manuscript: Silva PGMB, Sznejder H, Vasconcellos R, Charles GM, Dukacz S; Critical revision of the manuscript for intellectual content: Silva PGMB, Sznejder H, Vasconcellos R, Charles GM, Mendonca-Filho HTF, Mardekian J, Nascimento R, Dukacz S, Di Fusco M. Potential Conflict of Interest Silva PGMB reports to have received fees and research grants from Pfizer; Mardekian J, Nascimento R and Di Fusco M report being Pfizer employees. Sources of Funding This study was funded by Pfizer. Study Association This study is not associatedwith any thesis or dissertationwork. 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