Predictors Of Nonadherence To Warfarin In Discharged Patients After Mechanical Heart Valve Replacement

Objectives To investigate adherence to warfarin, knowledge of anticoagulation, belief about warfarin and social support in discharged patients after mechanical heart valve replacement, and explore the predictors of patients’ nonadherence to warfarin so as to make the targeted intervention strategies, improve patients’ adherence to warfarin and reduce anticoagulation complications, but also provide a reference basis for the application to other chronic patients’ medication adherence research and realizing the goal of drug use more safe, effective and conservation, and for the formulation of our management system about medication adherence.Methods Subjects were selected from a convenience sample that patients with mechanical heart valve replacement during January in2011to February in2012in an three level of first-class university affiliated hospital. The study conducted the questionnaire survey by telephone interview. From January1st,2012to August31th, investigation was implemented and Questionnaires were filled by the investigator according to answers of the subjects. The questionnaires included five parts:the general information questionnaire, the Chinese Revised8Item Morisky Medication Adherence Scale (MMAS-8), Knowledge of Anticoagulation with Warfarin Questionnaire, Beliefs about Medicines Questionnaire (BMQ-Specific), Social Support Rating Scale (SSRS). Using SPSS17.0statistical software for data entry and analysis, including descriptive analysis, nonparametric test-rank sum test (Mann-Whitney U test for comparison between two groups, Kruskal-Wallis H test for comparison including more than two groups, rank transformation analysis for multiple comparison between two samples), Spearman correlation analysis and multiple linear stepwise regression analysis.Results A total of204patients were investigated by telephone interview and182(89.22%)effective questionnaire have been got. Detailed information was as follows:1. The MMAS-8scores was7.22±0.95for discharged patients after MHVR, and overall in the medium level,52.20%of the patients adherence to warfarin is high, medium and low adherence level account for35.16%and12.64%, respectively;2. The MMAS-8scores’differences in difference population sociology and disease characteristics of patients with MHVR have statistical significance:the MMAS-8scores in youth (44years old or less), illiteracy and primary school,family per capita monthly income less than1000RMB, medical payment with New Rural Cooperative Medical System, not merge other drugs, anticoagulation without control, occurrence of anticoagulant complications, and cardiac function Ⅲ level were less than that of45～59years old and60and above, high school and above,1000-2000RMB,2000～3000RMB and more than3000RMB, medical insurance, merge one and two other drugs, anticoagulation control, without anticoagulation complications,and cardiac function Ⅰ level and Ⅱ level;3. The warfarin anticoagulation knowledge scores was10.63±4.32for discharged patients after MHVR, and98.90%from the medical staff, the scores of knowledge was correlated with the MMAS-8(r=0.537,P<0.01);4. The BMQ-Specific to warfarin scores was11.07±3.90, the necessity dimension scores was22.24±2.28, concern dimension scores was11.16±2.62, all of which were significantly related to MMAS-8and in addition to the concern dimension were positively correlated(correlation coefficients were0.509,0.460and-0.332, respectively, P<0.01);5. The SSRS scores was46.37±6.30for discharged patients after MHVR, the objective support dimension score for11.79±2.55, subjective support dimension score for26.35±3.09and the degree of support use dimension score for8.24±2.17, above all the variable scores were positively correlated to MMAS-8(correlation coefficients were0.512,0.346,0.454and0.428, respectively, P<0.01);6. Multiple linear stepwise regression analysis for MMAS-8showed that, anticoagulation knowledge score, social support score, concern(negative), cardiac function(compared with cardiac function Ⅰ level, patients of cardiac function Ⅱ level warfarin adherence more higher,while cardiac function Ⅲ level more low), degree of education(compared with illiteracy, high school and above patients adherence to warfarin more higher) and age(compared with44years or less,45-59years old warfarin adherence higher) were predictor variables of nonadherence to warfarin in discharged patients after mechanical heart valve replacement, which can explain53.6%of the total variance.Conclusion1. Discharged patients after MHVR nonadherence to warfarin is not optimistic,47.80%of the patients adherence to warfarin at the middle and low level, and improving patients warfarin adherence to be solved urgently, which is particularly important to anticoagulation control and reducing the complications of anticoagulant;2. The age, educational level, family per capita income, medical payment, merger other drug species, anticoagulation control,anticoagulation complications and the cardiac function level were significantly correlated with patients adherence to warfarin, patients of youth (44years old or less), illiteracy, family per capita monthly income less than1000RMB, medical payment with New Rural Cooperative Medical System, not merge other drugs, anticoagulation without control, occurrence of anticoagulant complications, and cardiac function Ⅲ level had lowest warfarin adherence.3. Lake of knowledge of anticoagulation,obtain or use less social support,taking warfarin concern belief more stronger, patients adherence to warfarin much lower, at the same time,clinical medical personnel should pay more attention to high-risk patients of cardiac function Ⅰ level and Ⅲ level, illiteracy and youth (44years old or less).