Patient knowledge of anticoagulant treatment does not correlate with treatment quality

Assessment of the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation: A systematic review and meta-analysis

The present study aimed to investigate the relationship between the level of patient knowledge on warfarin therapy and the quality of oral anticoagulation. This is a systematic review and meta-analysis written on the basis of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Searches at MEDLINE, EMBASE, Scopus and LILACS electronic databases were carried out on February 13, 2023, using the descriptors "Patient Medication Knowledge", "Patient Education as Topic", "Health Education", "Patient Education" and Warfarin. The steps of selection, data extraction and quality analysis of articles were performed independently by two reviewers. The analysis was performed considering patient knowledge as a possible modifier of time in therapeutic range (TTR). The meta-analysis included studies that reported the correlation coefficient (Pearson or Spearman) between patient knowledge and TTR. A subgroup analysis was performed according to questionnaires employed to measure patient knowledge. Twelve studies were selected with an overall sample size of 7634 participants and mean age 58.2 (standard deviation (SD)±12,8) years. Eleven (92.0%) cross-sectional studies. The mean TTR was 57.8% (SD±11,3%) and the average level of knowledge was 60.4%. The meta-analysis indicated that patient level of knowledge on warfarin therapy was moderately associated with TTR (rs = 0.435; 95% confidence interval (CI) = 0.163-0.645; I2 = 96%). Subgroup analysis indicated association between knowledge level and TTR in studies employing the OAK test (rs = 0.617; 95% CI = 0.192-0.847; I2 = 97%) and the AKA (rs = 0.269; 95% CI = 0.002 to 0.501; I2 = 94%). However, the subgroup analysis presented no significant difference between them (p = 0.14). The meta-regression showed a non-significant negative effect of age on the correlation (estimate = -0.028, 95% CI = -0.073 to 0.016, p = 0.207). No publication bias was noted (p = 0.881). To our knowledge, this is the first systematic review and meta-analysis gathering evidence about the relationship between the level of patient knowledge on oral anticoagulation with warfarin and TTR. The implementation of structured and patient-centered educational interventions is essential to effectively increase the level of patient knowledge and, thus, to improve the quality and safety of warfarin therapy. Systematic review registration number: PROSPERO CRD42023398030.

Validation of a Knowledge Test in Turkish Patients on Warfarin Therapy at an Ambulatory Anticoagulation Clinic

Objectives

This study aimed to evaluate the validity and reliability of an oral anticoagulation knowledge (OAK) test in Turkish patients on warfarin therapy at an anticoagulant outpatient clinic.

Materials and Methods

This study was conducted at an ambulatory anticoagulation clinic and included patients older than 18 years who had been using warfarin for at least six months. Patients' demographic and clinical data were collected. Internal consistency was calculated using the Kuder-Richardson 20 (KR-20) coefficient, and the test-retest reliability of the Turkish version of the OAK test was assessed.

Results

Patients' mean age was 59.83±11.93 (26-90) years (n=240; 133 women). The mean score of the OAK test was 14.19±3.01. The test-retest reliability of the scale (n=30) was moderate for the total score (p<0.001). The KR-20 value, a measure of internal consistency, was 0.671. Patients of a younger age and higher educational level were more likely to have higher levels of anticoagulation knowledge than patients of an older age and lower education level (p<0.05 for both comparisons).

Conclusion

The Turkish version of the OAK test can be used to determine the patients' knowledge on oral anticoagulation.

Association between Patients' Knowledge and Adherence to Anticoagulants, and Its Effect on Coagulation Control

BACKGROUND

Warfarin requires strict monitoring by measuring prothrombin time (PT), international normalized ratio (INR), and time in therapeutic range (TTR). Several factors can lead to poor PT/INR control including vitamin K status, medication adherence, knowledge, and quality of life. The present study aims to assess patient adherence to warfarin treatment and its correlation with INR control.

METHODS

A cross-sectional study was conducted between October 2017 and January 2018 at Tripoli University Hospital. Data were collected by structured questionnaires which included; demographic and clinical characteristics, the Oral Anticoagulation Knowledge (OAK) test, and the Morisky Medication Adherence Scale (MMAS-8).

RESULTS

The final analysis included 88 out of 140 patients (73.33%). There were significant differences in age range, gender, marital status, and education level between the 2 groups (poor knowledge and adequate knowledge) (p < 0.05). There was a significant positive correlation between OAK test score and TTR. Overall, 76.2% of patients were adherent to warfarin (MMAS score ≥6) and 20.45% of patients were of high adherence (MMAS score of 8). The median score was 6 (IQR 6-7). A statistically significant, strong positive correlation between adherence to medication and TTR as an indicator of INR control was found (rs[86] = 0.472, p < 0.0001).

CONCLUSION

The study addressed and identified several areas for future improvement of patient outcomes. The implementation of new approaches to enhance patient knowledge and adherence is warranted, and measures to provide treatment for all patients that require it are needed, to improve outcomes and decrease adverse drug effects.

The effect of warfarin knowledge on anticoagulation control among patients with heart valve replacement

Background Although novel oral anticoagulants have been applied into clinical practice, warfarin remains the only approved oral anticoagulant for heart valve replacement. Currently, an increasing number of Chinese clinical pharmacists provide patients with warfarin education. However, little research to date has been carried out to evaluate the relationship between warfarin knowledge level and anticoagulation control among patients with heart valve replacement. Objective To evaluate knowledge of warfarin and the relationship between knowledge level and anticoagulation control among patients with heart valve replacement. Setting Fujian Medical University Union Hospital, China. Method A prospective and cross-sectional study was designed to evaluate the warfarin education of inpatients new to warfarin therapy using a validated Anticoagulation Knowledge Assessment questionnaire. Included patients were followed up for at least 3 months. Data were retrieved from hospital databases and telephone follow up. Main outcome measure Spearman's rho correlation analysis was used to assess the relationships between time in therapeutic range and warfarin knowledge level. Results 383 patients were included. The mean age of patients was 50.3 ± 7.9 years. The mean knowledge questionnaire score was 62.3 ± 8.8%. The majority of incorrect answers related to drug-warfarin interaction. Five of the frequently incorrect questions covered drugs, herbs and diet that affect warfarin therapy. There were significant correlations between total questionnaire score and time in therapeutic range (rho = 0.539, P < 0.001), or percentage of international normalized ratio measurements within range (rho = 0.416, P < 0.001). There were significant correlations between patients' educational level and total questionnaire score (rho = 0.357, P = 0.001). No significant correlations were found between income or living area and total questionnaire score (rho = 0.110, P = 0.435; rho = 0.161, P = 0.149). Conclusion Patient knowledge level of anticoagulation therapy affects anticoagulation control. Education for patients new to warfarin and the evaluation of knowledge by validated questionnaire is recommended for better INR control.