Impact of telephone follow-up in patient's health-related quality of life during the first six months of warfarin use: randomized clinical trial

Warfarin is an oral anticoagulant, antivitamin K, widely used in the prevention of intravascular thrombi of different etiologies. It requires rigorous and complex control as a result of its interaction with other drugs and foods, which may interfere with users' Quality of Life Related to Health (HRQoL). Educational interventions have been used to lessen the impact of this therapy. The main objective was to compare the HRQoL, at three and six months after discharge, of two groups of patients who started using warfarin for the first time during hospitalization. Secondary objectives, were to compare the presence of anxiety and depression symptoms and the adequacy of the International Normalized Ratio (INR) value in the indicated therapeutic range, between the groups. It is an experimental study with random designation in two groups. The patients in the intervention group (IG) received the educational program with telephone follow-up after discharge and those in the control group (CG) received the educational program without telephone follow-up. The study was approved by the Research Ethics Committee and was enrolled in the ClinicalTrials.gov database. The research was conducted at the State Hospital of Ribeirão Preto and the Hospital Estadual de Américo Brasiliense and included patients who started using warfarin for the first time, over 18 years and with a telephone to contact. The educational program was guided by the Bandura Theory and was composed of verbal and written information about the treatment and approached during hospitalization. GI participants received five telephone contacts to reinforce this information after discharge. Both groups had two face-to-face meetings at three and six months for the evaluation of the outcome variables: HRQOL (assessed by the Brazilian version of the Duke Anticoagulation Satisfaction Scale - DASS) and symptoms of anxiety and depression (assessed by the subscales of Hospital Anxiety and Depression Scale - HADS). To compare the DASS and the HADS scales, we performed Student's t-test for independent samples. In order to compare the groups over time, in relation to HRQoL, we performed Variance Analysis (ANOVA) for repeated measures, taking as factors the time (three and six months), the group (intervention or control) and a time interaction per group. The level of significance was set at 0.05. The groups were similar in sociodemographic and clinical characterization. The majority of the participants were married, female and with an average age of 55 years (D.P = 15). The most frequent indications for the initiation of warfarin were deep venous thrombosis and pulmonary thromboembolism. We did not find statistically significant differences between the means of HRQoL, anxiety and depression of the two groups at three and six months after discharge