Self-report instruments for assessing adherence to warfarin therapy: a systematic review.

BACKGROUND: The assessment of adherence to warfarin therapy is useful in clinical practice due to its wide variability in dose-response and risks of complications. The aim of this study was to investigate validated instruments used to assess adherence to warfarin therapy. METHODS: Information was collected from the MEDLINE (PubMed), LILACS, EMBASE, and Cochrane Library databases. Search strategies were applied for each database, with no time limit or language restriction. Inclusion criteria consisted of study participants of ≥ 18 years of age, from both sexes, on chronic anticoagulation with warfarin for any indication and the use of validated instruments to assess adherence to warfarin therapy. Exclusion criteria consisted of duplicate articles, narrative or systematic reviews, and meta-analyses, as well as case reports/series and experimental studies involving animals. Two independent reviewers performed the following steps: evaluation of titles/abstracts, selection of studies after full reading, data extraction, and evaluation of potential bias. Discrepancies were resolved by a third reviewer. RESULTS: Overall, 19 articles were selected for this systematic review, including 17 cross-sectional studies, one cohort study, and one quasi-experimental study, published from 2009 to 2019. The validated instruments identified in this review were Morisky Medication Adherence Scale (MMAS), the eight-item Morisky Medication Adherence Scale (MMAS-8), Measurement of Treatment Adherence (MTA), and Brief Medication Questionnaire (BMQ). Only MMAS-8 was tested for reliability, using the internal consistency assessment, with Cronbach's α range 0.56-0.71. CONCLUSIONS: This review highlighted a gap in knowledge regarding the scarcity of validated instruments to assess adherence to warfarin therapy. Limitations were found in instruments that comprised the assessment of the isolated use of medication and the lack of analysis of other relevant therapeutic aspects. Future studies are needed to develop and validate more comprehensive instruments in an attempt to assess adherence to warfarin therapy. PROSPERO: Registration number CRD42019128324.

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.

Influence of sex-based differences on oral anticoagulation control in patients taking coumarin derivatives: a systematic review protocol.

OBJECTIVE: This review will aim to assess the influence of sex-based differences on oral anticoagulation control in patients taking coumarin derivatives. INTRODUCTION: Coumarin derivatives, such as warfarin, have a narrow therapeutic index, requiring frequent monitoring to achieve adequate anticoagulation control, which can be assessed by the time in therapeutic range. Differences in the quality of oral anticoagulation control between men and women have been reported, although the current evidence is controversial. A systematic review on this topic would provide results that could be incorporated into clinical practice to enhance oral anticoagulation control and treatment outcomes. INCLUSION CRITERIA: Observational and experimental studies were assessed for eligibility, with participants aged ≥18 years of either sex taking oral anticoagulation or other coumarin derivatives for ≥3 months, for any indication of chronic use, who had oral anticoagulation control evaluated by time in therapeutic range. METHODS: Electronic databases to be searched include MEDLINE, BVS, CINAHL, Embase, Cochrane CENTRAL, and Web of Science. Two reviewers will independently perform title/abstract selection and screening, and then full text retrieval and screening of articles that meet the inclusion criteria. The evaluation of methodological quality and data extraction will also be performed by two independent reviewers. Data will be synthesized in tables and then the compiled results will be meta-analyzed. In the presence of subgroup differences, meta-regression methods will be used to investigate the effects of categorical or continuous covariates. If statistical pooling is not possible, a narrative synthesis will be presented. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO (CRD42019128329).