Pattern of warfarin related complications and Anticoagulation profile among patients on regularWarfarin therapy at Muhimbili national hospital

Abstract

Background: Warfarin is a synthetic oral anticoagulant of choice in Tanzania and commonlyused worldwide. Management of its anticoagulation effect remains a challenge due toanticoagulation shortfalls among patients on regular warfarin therapy. This study aimed to determine the anticoagulation profile, prevalence of complications associated with warfarin therapy and to study the reliability of INR measurements among patients on regular warfarin therapy attending hematology anticoagulation clinic at MNH. Methodology: This was a cross sectional study, which included 190 patients on regular warfarin therapy, attending hematology anticoagulation clinic at MNH. Blood samples were taken from the recruited patients for laboratory tests which included INR measurements. Other clinical records were obtained from patients’ medical records and from interviews. Data collected were coded and analyzed by Statistical Package for Social Sciences (SPSS) version 22 computer software. A Chi square test was used to test for associations between INR and the independent variables whereby a p-value of < 0.05 was regarded as a significant association. Results: The commonest indication for anticoagulation was Mechanical Heart Valve Replacement (68.9%). Only 20% of the study participants had their INR within the therapeutic range. Out of all the study participants, 20.5% reported to have experienced warfarin induced bleeding whereas 3.2% reported to have experienced thromboembolic complications. There was no considerable noted influence of the studied risk factors on INR and warfarin related complications. Repeated INR measurements did not show significant variation. Conclusion: Complications related to warfarin therapy are evident and poor anticoagulation profile was reflected by majority of the patients who didn’t achieve the target INR. Having adhering patients to warfarin therapy yet showing non therapeutic INR indicates that though INR is presently indispensable, yet it should be used cautiously as a sole indicator and additional clinical assessments should be made in patients showing persistent non-therapeutic INR.