Abstract
Objective There has been a lack of evidence of the effects of pharmacist-managed warfarin therapy (PMWT) in developing countries (e.g. Southeast Asian countries) where the patients’ characteristics, genetic make-up, clinical practice and healthcare system are different from the Western world. This study aimed to compare the anticoagulation control and clinical outcomes associated with warfarin therapy provided by PMWT to usual care (UC) in the Thai population. Setting A 1,000-bed tertiary-care hospital in Nakornratchasima province of Thailand. Method A quasi-experimental study comparing PMWT and UC in patients receiving long-term warfarin therapy. For PMWT group, clinical pharmacists optimised the warfarin therapy and suggested recommendations (e.g. dose adjustment, safer alternative drugs, and follow-up time) to physicians. The UC group received the standard care. Main outcome measure Time in therapeutic range (TTR), both actual- and expanded-TTR, bleeding and thromboembolic complications, and physician’ acceptance of pharmacist suggestions. Results Of 433 patients enrolled, 220 and 213 were in the PMWT and UC groups respectively. At baseline, patient’s characteristics of both groups were comparable. At the end of follow-up period, patients in the PMWT group had significantly higher actual-TTR (48.3% vs. 40.1%; P < 0.001) and expanded-TTR (62.7% vs. 53.9%; P < 0.001) compared to those in the UC group. Rates of major bleeding were 4.4 vs 4.5 events per 100 person-years for the PMWT and UC groups, respectively. Pharmacists performed 284 interventions with an acceptance rate of 80.3% from physicians. Conclusion Pharmacist-managed warfarin therapy resulted in a significantly better anticoagulation control. This study showed that a collaborative approach in anticoagulation management can be successfully implemented in a developing country. Implementation of such care model in other developing countries should be considered.
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References
Ansell J, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th edition). Chest. 2008;133:160S–98S.
Hylek EM, Chang YC, Skates SJ, Hughes RA, Singer DE. Prospective study of the outcomes of ambulatory patients with excessive warfarin anticoagulation. Arch Intern Med. 2000;160:1612–7.
Saokaew S, Permsuwan U, Chaiyakunapruk N, Nathisuwan S, Sukonthasarn A. Effectiveness of pharmacist-participated warfarin therapy management: a systematic review and meta-analysis. J Thromb Haemost. 2010;8:2418–27.
Chiquette E, Amato MG, Bussey HI. Comparison of an anticoagulation clinic with usual medical care: anticoagulation control, patient outcomes, and health care costs. Arch Intern Med. 1998;158:1641–7.
Jackson SL, Peterson GM, Vial JH, Jupe DML. Improving the outcomes of anticoagulation: an evaluation of home follow-up of warfarin initiation. J Intern Med. 2004;256:137–44.
Lalonde L, Martineau J, Blais N, Montigny M, Ginsberg J, Fournier M, et al. Is long-term pharmacist-managed anticoagulation service efficient? A pragmatic randomized controlled trial. Am Heart J. 2008;156:148–54.
Poon IO, Lal L, Brown EN, Braun UK. The impact of pharmacist-managed oral anticoagulation therapy in older veterans. J Clin Pharm Ther. 2007;32:21–9.
Wilson SJ-A, Wells PS, Kovacs MJ, Lewis GM, Martin J, Burton E, et al. Comparing the quality of oral anticoagulant management by anticoagulation clinics and by family physicians: a randomized controlled trial. Can Med Assoc J. 2003;169(4):293–8.
Witt DM, Sadler MA, Shanahan RL, Mazzoli G, Tillman DJ. Effect of a centralized clinical pharmacy anticoagulation service on the outcomes of anticoagulation therapy. Chest. 2005;127:1515–22.
Matsuyama K, Matsumototo M, Sugita T, Nishizawa J, Yoshida K, Tokuda Y, et al. Anticoagulant therapy in Japanese patients with mechanical mitral valves. Circ J. 2002;66:668–70.
Tientadakul P, Sangtawesin W, Opartkiattikul N, Luenee P, Sakiyalak P. Retrospective evaluation for optimal oral anticoagulant intensity after mechanical heart valve replacement at Siriraj Hospital. Thail Heart J. 1994;7:97–102.
Lee LH. Thrombotic and haemorrhagic complications in patients with mechanical heart valve prostheses attending in Singapore General Hospital. Ann Acad Med Singap. 2000;29:71–4.
Weibert RT, Palinkas LA. Differences in warfarin dose requirements between Asian and Caucasian patients. Clin Pharmacol. 1991;49:151.
Chan FWH, Wong RSM, Lau W-H, Chan TYK, Cheng G, You JHS. Management of Chinese patients on warfarin therapy in two models of anticoagulation service—a prospective randomized trial. Br J Clin Pharmacol. 2006;62(5):601–9.
Pengo V, Pegoraro C, Cucchini U, Iliceto S. Worldwide management of oral anticoagulant therapy: the ISAM study. J Thromb Thrombolysis. 2006;21(1):73–7.
Ansell J, Hollowell J, Pengo V, Martinez-Brotons F, Caro J, Drouet L. Descriptive analysis of the process and quality of oral anticoagulation management in real-life practice in patients with chronic non-valvular atrial fibrillation: the international study of anticoagulation management (ISAM). J Thromb Thrombolysis. 2007;23(2):83–91.
Saokaew S, Suwankesawong W, Permsuwan U, Chaiyakunapruk N. Safety of herbal products in Thailand: an analysis of reports in the Thai health product vigilance center database from 2000 to 2008. Drug Saf. 2011;34(4):339–50.
Boonbaichaiyapruck S, Panchavinnin P, Suthichaiyakul T, Benjanuwatra T, Sukanandachai B, Mahawanakul W, et al. Behavior of prothrombin time (INR) in response to warfarin therapy in a Thai population. Thail Heart J. 2006;19:85–9.
Hirsh J, Fuster V, Ansell J, Halperin JL. American Heart Association/American College of Cardiology Foundation guide to warfarin therapy. Circulation. 2003;107:1692–711.
Ansell J, Hirsh J, Dalen J, Bussey H, Anderson D, Poller L, et al. Managing oral anticoagulant therapy. Chest. 2001;199:22S–38S.
Bates S, Greer IA, Hirsh J, Ginsberg JS. Use of antithrombotic agents during pregnancy. Chest. 2004;126:627–44.
Rosendaal FR, Cannegieter SC, van der Meer FJM, Briet E. A method to determine the optimal intensity of oral anticoagulant therapy. Thromb Haemost. 1993;69(3):236–9.
Schulman S, Kearon C, on behalf of the subcommittee on control of anticoagulation of the Scientific and Standardization committee of the International Society on Thrombosis and Haemostasis. Definition of major bleeding in clinical investigations of antihemostatic medicinal products in non-surgical patients. Scientific and Standardization Committee Communication. J Thromb Haemost. 2005;3:692–4.
Sapoo U. Impact of physician-pharmacist collaboration on the management of warfarin therapy. Bangkok: Mahidol University; 2006.
Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies for causal effects. Biometrika. 1983;70(1):41–55.
D’Agostino RB. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med. 1998;17:2265–81.
Patrick AR, Schneeweiss S, Brookhart MA, Glynn RJ, Rothman KJ, Avorn J, et al. The implications of propensity score variable selection strategies in pharmacoepidemiology: an empirical illustration. Pharmacoepidemiol Drug Saf. 2011;20(6):551–9.
Kim HT. Cumulative incidence in competing risks data and competing risks regression analysis. Clin Cancer Res. 2007;13(2):559–65.
Lau B, Cole SR, Gange SJ. Competing risk regression models for epidemiologic data. Am J Epidemiol. 2009;170:244–56.
Samsa GP, Matchar DB. Relationship between test frequency and outcomes of anticoagulation: a literature review and commentary with implications for the design of randomized trials of patient self-management. J Thromb Thrombolysis. 2000;9:283–92.
Kaatz S. Determinants and measures of quality in oral anticoagulation therapy. J Thromb Thrombolysis. 2008;25:61–6.
Bieobanjong S. The clinical outcomes of pharmaceutical care on warfarin in out-patients at Chiangrai Regional Hospital. Chiang Mai: Chiang Mai University; 2000.
Liabthawee W. Impact of education and counseling by clinical pharmacists on anticoagulation therapy in patients with mechanical heart valves. Bangkok: Mahidol University; 2004.
Munjamroon Y, Suttajit S, Tammarat T, Saritreechaikun D. Clinical outcomes of warfarin monitoring in outpatients at Nakorn Phanom Hospiatal. J Sci Technol MSU. 2007;26(1):38–46.
Katemateegaroon D. Warfarin related problems and comparison of patient outcomes between pharmacist-assisted anticoagulation service and usual medical care in ambulatory patients. Khon Kaen: Khon Kaen University; 2002.
Beyth RJ, Quinn LM, Landefeld CS. Prospective evaluation of an index for predicting the risk of major bleeding in outpatients treated with warfarin. Am J Med. 1998;105:91–9.
Singer DE, Albers GW, Dalen JE, Go AS, Halperin JL, Manning WJ. Antithrombotic therapy in atrial fibrillation: the seventh ACCP conference on antithrombotic and thrombolytic therapy. Chest. 2004;126:429S–56S.
Dunn AS, Turpie AGG. Perioperative management of patients receiving oral anticoagulants. Arch Intern Med. 2003;163:901–8.
Acknowledgments
We would like to acknowledge and thank the Maharat Nakornratchasima Hospital for granting permission to use data provided in this study and Prof. Dr. Jayanton Patumanond for statistics suggestion. We gratefully acknowledge Dr. Bancha Sookananchai, Dr. Damri Sethachinda, Dr. Tongprakob Siriwanij, Mrs. Amonrat Pangthaisong, CCTS staffs, and all pharmacists for their significant contribution for this project.
Funding
The grant was supported by the Office of the Higher Education Commission, Ministry of Education, Thailand, under the program Strategic Scholarships for Frontier Research Network for the Ph.D. Program Thai Doctoral degree.
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Saokaew, S., Sapoo, U., Nathisuwan, S. et al. Anticoagulation control of pharmacist-managed collaborative care versus usual care in Thailand. Int J Clin Pharm 34, 105–112 (2012). https://doi.org/10.1007/s11096-011-9597-8
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DOI: https://doi.org/10.1007/s11096-011-9597-8