Author, year. Aim | Methods | Instrument for measuring HL | OAC medication | Risk of Bias (according to ICROMS tool) |
Diug, Evans et al. 2011 Evaluate impact of psychosocial factors (social isolation, HL, cognitive abilities) in OAC treatment. | aCase-control study. Control: Patients with INR in therapeutic range. Cases: previously stabilized patients who registered INR ≥ 6 aSample: 486 patients (157 cases and 329 controls) aStructured interview of 1 h to identify risk factors. Interview after 30 days. aData collection: - Medical history (INR) - Socio-demographic data - Comorbidities, cognitive function… | aS-TOFHLA - Limited HL (0–22 points) - Adequate HL (23–36 points) | aWarfarin | aPossible Patient memory bias aNeither interviewers nor patients blinded to obtain cases ICROMS Score: 24 S1:2; S2:2; S3: 5; S4:2; S5:2; S6:2; S7: 9 |
Dolor, Ruybalid et al. 2010 Evaluate if home self-control test (PST) improves the quality of anticoagulation and decreases complications | aRandomized Controlled Trial aSample: 2922 patients. aTraining to handle PST aData collection: - Medical history (INR) - SPMSQ (Assesses cognitive status) - ABILHAND (Measure dexterity) - DASS (Duke anticoagulation satisfaction scale). Quality of life | aREALM Scale | aWarfarin | aOnly Veteran patients with AF or valve replacement (selection bias) ICROMS Score: 28 S1:2; S2:4; S3:6; S4:6; S5:1; S6:2; S7:7 |
Estrada, Martin-Hryniewicz et al. 2004 Determine prevalence of low HL in OAC patients and to assess if there is association with anticoagulation control. | aProspective cohort study aSample: 143 patients. aData collection: - Socio-demographic data - Medical history (dose in mg/week, number of dose changes, number of visits without going, indication of anticoagulation) - INR: monitoring for 3 months. - Time Therapeutic Range (TTR) aVariability of INR was measured by Sigma (INR number, time from the last INR and INR suitable for that patient) | aREALM Scale | aWarfarin | aREALM scale only values reading level, non-comprehension (functional HL) aOnly English-speaking patients were assessed. aComplications are not measured. ICROMS Score: 23 S.1:2; S2:2; S3:5; S4:2; S5:1; S6:2; S7:9 |
Fang, Machtinger et al. 2006 Assess the association between HL and warfarin knowledge, adherence and control. | aObservational, descriptive study aSample: 179 patients. aData collection: - INR - S-CASI (Assesses cognitive abilities) - 4 questions regarding anticoagulation and safe use of warfarin aINR control every 4–6 weeks. aAdherence to treatment: last time they forgot to take warfarin, if they forgot 1 dose in the last 2 weeks or in the last 2 days. | aS-TOFHLA Scale. - Limited HL (0–22 points) - Adequate HL (23–36 points) | aWarfarin | aOnly includes patients who speak English or Spanish aSelf-made questionnaire concerning knowledge of anticoagulation aSelf-report adherence measure (recall bias) aComplications are not measured. ICROMS Score: a |
Fang, Panguluri et al. 2009 To assess the relationship between HL and patients with stroke with warfarin to assess perceived information and improve communication. | aObservational, descriptive study aSample: 183 patients. aData collection: - Medical history - Socio-demographic data - S-CASI (cognitive abilities) - Questionnaire of two open questions: why do you take warfarin and what is a stroke? Classification answers: concordant /discordant | aS-TOFHLA Scale. - Inadequate HL (0–16) | aWarfarin (For at least 3 months) | aOnly 2 open questions, insufficient to explore subjects’ perception aRelationship between HL and open-ended questions not validated aSample obtained in a single center (selection bias) aOnly patients with stroke ICROMS Score: -a |
Oramasionwu, Bailey et al. 2014 Assess the relationship between HL and anticoagulation control (TTR) | aObservational, descriptive study aSample: 198 patients. aData collection: - Medical history - INR / TTR - Socio-demographic data (annual income) - Questionnaire to evaluate understanding of anticoagulant treatment (Fang et al. 2006) | aS-TOFHLA (36 items of reading comprehension and 4 items of multiple questions of arithmetic). 100 points. - Limited HL: 0–90 -Adequate HL: 91–100 | aWarfarin | aNot assess the appearance of complications. * Not incorporate factors that could modify INR (diet, other medicines) *aOnly English-speaking patients were included ICROMS Score: -a |
Schillinger, Machtinger et al. 2006 To relate verbal-visual communication with medication management | aObservational, descriptive study aSample: 220 patients. aData collection: - Medical history (INR) - S-CASI (Assesses cognitive abilities) - Number of days they forgot to take warfarin week prior to study | aS-TOFHLA Scale - Inadequate HL (0–16) | aWarfarin | aReduced sample size * Method used to determine agreement of treatment (does not determine if visual agreement greater than verbal) ICROMS Score: a |
Schillinger, Wang et al. 2006 To examine if there is a mismatch between the anticoagulant treatment that the patient takes and the standard. Assess adherence | aObservational, descriptive study aSample: 220 patients. aData collection: - Medical history (INR) a-Adherence (n° of times forgot to take the treatment in 30 days) aS-CASI (cognitive abilities) aAgreement of treatment: evaluated concordance of the weekly mg. | aS-TOFHLA (English and Spanish) - Inadequate HL (0–16) | aWarfarin | aA single clinic is included. aMeasurement of adherence subject to recall bias and social acceptability bias. ICROMS Score: a |
Wilson, Racine et al. 2003 To investigate the level of HL and to evaluate the readability and cultural sensitivity of the information administered in an anticoagulation clinic | aDescriptive, correlational study aSample: 65 patients. aDesigned an easy-to-read aducational/ informative material. aOnce a week patients were interviewed about diet, medicine control + 15 min. of education for health. aData collection: - Medical history (INR) - Socio-demographic data (annual income) - Self-made warfarin knowledge questionnaire (20 items) - SMOG formula (to assess the reading difficulty level of the guide) | aREALM Scale | aWarfarin | aSelf-made questionnaire concerning knowledge of warfarin aReduced sample size aDoes not relate INR with HL. aComplications are not measured. ICROMS Score: 19 S1:2; S2:2; S3:4; S4:2; S5:0 S6:2; S7: 7 |
Wilson, Templin et al. 2015 To evaluate the psychometric properties of the KIP-C20 test | aDescriptive, correlational study aSample: 192 patients. aCreation KIP-C14 test. aData collection: - Socio-demographic data (annual income) - KIP-C20 test: Knowledge Information Profile-Coumadin. 20 items with response T/F. 2 weeks the KIP-C20 test was administered again. - Animal Naming Test (ANT): To assess cognitive ability | aREALM Scale | aCoumadin | aUse sample from a single center. (Similar economic level of patients) aNo complications or adherence to treatment were measured aLimited to coumadin medicine ICROMS Score: 21 S1:2; S2:2; S3:4; S4:2; S5:0 S6: 2; S7:9 |