Evaluation of patients' knowledge about anticoagulant treatment.

OBJECTIVE--To develop a questionnaire to evaluate patients' knowledge of anticoagulation. DESIGN--Anonymous self completed questionnaire study based on hospital anticoagulant guidelines. SETTING--Anticoagulant clinic in a 580 bed district general hospital in London. SUBJECTS--70 consecutive patients newly referred to the anticoagulant clinic over six months. MAIN MEASURES--Information received by patients on six items of anticoagulation counselling (mode of action of warfarin, adverse effects of over or under anticoagulation, drugs to avoid, action if bleeding or bruising occurs, and alcohol consumption), the source of such information, and patients' knowledge about anticoagulation. RESULTS--Of the recruits, 36 (51%) were male; 38(54%) were aged below 46 years, 22(31%) 46-60, and 10(14%) over 75. 50 (71%) questionnaires were returned. In all, 40 respondents spoke English at home and six another language. Most patients reported being clearly advised on five of the six items, but knowledge about anticoagulation was poor. Few patients could correctly identify adverse conditions associated with poor control of anticoagulation: bleeding was identified by only 30(60%), bruising by 23(56%), and thrombosis by 18(36%). Only 26(52%) patients could identify an excessive level of alcohol consumption, and only seven (14%) could identify three or more self prescribed agents which may interfere with warfarin. CONCLUSION--The questionnaire provided a simple method of determining patients' knowledge of anticoagulation, and its results indicated that this requires improvement. IMPLICATIONS--Patients' responses suggested that advice was not always given by medical staff, and use of counselling checklists is recommended. Reinforcement of advice by non-medical counsellors and with educational guides such as posters or leaflets should be considered. Such initiatives are currently being evaluated in a repeat survey.