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J R Soc Med. Apr 2003; 96(4): 175–179.
PMCID: PMC539445

Patients' understanding of anticoagulant therapy in a multiethnic population


To investigate whether knowledge and perceptions of antithrombotic therapy differ between ethnic groups in the UK, we conducted a cross-sectional questionnaire survey of patients attending anticoagulation clinics in three Birmingham teaching hospitals. 180 consecutive patients were recruited—135 white European, 29 Indo-Asian, 16 Afro-Caribbean.

The average knowledge score was 5.5 out of 9, with no significant differences between the groups. Indo-Asians were significantly less likely than the other groups to know the name of the anticoagulant they were taking (warfarin) and Afro-Caribbeans to know the condition for which they were being anticoagulated. Few patients of any group were able to specify more than one side-effect of warfarin or the dose they were on. In logistic regression analysis the factors associated with a low score were age >61 years, having been born outside the UK, and the perception of difficulty in comprehension. Nearly half the Indo-Asians felt unable to understand what was said to them in the clinic, and 62% expressed a preference for a doctor of the same ethnic group.

Although there were no significant between-group differences, this study points to gaps in the knowledge of patients from ethnic minorities and to deficiencies in the provision of information. In patient education, these groups should receive special attention.


Increasing numbers of patients are receiving the anticoagulant warfarin for prevention of thromboembolism from deep-vein thrombosis, atrial fibrillation or a prosthetic heart valve.1 The dose-response relation is complex and activity of the drug is easily altered by concurrent medications and illnesses. Adherence to medical advice and routine monitoring of the international normalized ratio (INR) are therefore important, and in England the service is usually provided by specialized anticoagulation clinics.2,3

There is good evidence4,5,6,7,8,9 that adherence to medical treatment is enhanced by knowledge and understanding of the drug, its benefits and its side-effects. Other influences are the views of family and friends, societal pressures and cultural or ethnic background. Ethnicity is an important factor, especially when there are language difficulties.10,11,12,13 Also, racial background is a determinant of average warfarin dose.14 In a previous paper we showed that many patients with atrial fibrillation who attended an anticoagulant clinic were ill-informed about the disease process and the need for antithrombotic therapies.15 Moreover, there were significant differences between ethnic groups in knowledge of atrial fibrillation and of the risks, actions, and benefits of warfarin. We therefore hypothesized that deficiencies in patient understanding and disease perceptions would be apparent in relation to anticoagulant therapy. To investigate this further, we conducted a cross-sectional survey of a multiethnic patient population attending anticoagulation clinics in Birmingham.


Consecutive patients attending the anticoagulation clinics at three large teaching hospitals (Selly Oak Hospital, Birmingham Heartlands Hospital and City Hospital) were recruited over five months. These hospitals serve a patient catchment area of >750 000, with an ethnic mix of about 25% Indo-Asian, 11% Afro-Caribbean, and 64% white European. Most of the Indo-Asians are of Punjabi origin. In this catchment population, more than 90% of patients on anticoagulants are monitored by the hospital anticoagulation clinic, where they are issued with the standard NHS yellow anticoagulant booklet. In most cases, they have been told about their illness and treatment by a junior doctor at the original hospital, even if the decision to anticoagulate was made by the consultant. No formal education on the matter is provided by the anticoagulation clinic, which in Birmingham is usually run by specialist nurses and doctors from the departments of haematology.

Our aim was to recruit, at each hospital, 60 patients who had attended the anticoagulation clinic at least six times (to make sure that they had enough exposure to the clinic and that time should not be a confounding factor). A standardized questionnaire was used, with questions on disease perception and adherence to warfarin therapy. The level of education was determined, since this would influence understanding of the disease and the therapy. The last page of the questionnaire was about sources of information and satisfaction with the information given by the doctor. The patients were scored 1 for every correct answer, with a maximum of 9. The scores were then categorized as low (< 3), medium (3-6) and high (> 6). The questionnaire was initially piloted and the patients were interviewed in standard fashion by three individuals fluent in English, Punjabi, Hindi and Urdu. Ethics committee approval was obtained and all patients gave informed consent to participation. Ability in the English language was self-scored out of a maximum of 12 points: patients scored 0-3 points each for the ability to understand, speak, read, and write English (0=no knowledge; 3=fully able to understand or speak or read). This is a crude measurement, but it is often used in epidemiological studies.

Data were expressed as mean and standard deviation, median and interquartile range or number and percentage as appropriate. Continuous data were analyzed by one-way ANOVA or the Kruskal—Wallis test, and categorical data by the χ2 test, for comparisons between the three main ethnic groups (white European, Afro-Caribbean, Indo-Asian). Logistic regression analysis was used to ascertain the relative risks for getting a low score. A P value of < 0.05 was taken as statistically significant.


186 patients were approached and 6 declined. Of the remaining 180, 135 (75%) were white European, 29 (16%) were Indo-Asian and 16 (9%) were Afro-Caribbean. The groups did not differ in sex ratio or education level, but the Indo-Asians were much younger and had a poorer knowledge of English (Table 1).

Table 1
Demographic distribution of the patients

Knowledge scores

Most of the patients in all three groups achieved either a medium or a high knowledge score (Table 2). The scores did not differ significantly from group to group. Responses to the questions are detailed in Table 2. Indo-Asians were less likely than the other groups to know the name of the drug. 94% of patients knew what type of drug warfarin is, but only 54% knew why they were taking it and what dose they were on. The others were simply taking the drug ‘because their doctor told them to’, and the dose was ‘whatever was written in the anticoagulant booklet’. When asked about potential side-effects, most could mention only one—increase in bleeding. All knew what would happen if they were to stop taking the warfarin.

Table 2
Responses to questions

Logistic regression analysis indicated that the following were factors in a low score: age >61 years (relative risk [RR] 1.3, 95% confidence interval [CI] 1.11-1.50, P<0.05); difficulty understanding the doctor (RR 4.3, CI 2.2-8.2, P<0.001); born outside the UK (RR 2.1, CI 1.3-3.6, P<0.009).

Patients' perceptions

45% of the Indo-Asian patients, compared with 18% of the white Europeans and 19% of the Afro-Caribbeans, felt they had difficulty understanding their anticoagulant management (P=0.04). In slight contradiction, three-quarters of Indo-Asians expressed satisfaction with the information that was given (perhaps thinking that the fault lay with themselves).

49% of the Indo-Asian patients attended the clinic with another person, whereas all the Afro-Caribbeans and 68% of the white Europeans attended alone (P=0.004). The reason that most of the Indo-Asians took a companion was to help them out with language problems, whereas in the case of the white Europeans it was for company. Probably for the same reason, 62% of the Indo-Asians preferred to have a doctor of the same ethnic origin, whereas the other two ethnic groups did not appear to mind (P<0.001).


This study is limited by its cross-sectional nature and its reliance on questionnaire-based interviews. In addition, there is the possibility that patients with different indications for anticoagulation had different amounts of education; for example, patients with atrial fibrillation might receive fuller explanations than those with deep-vein thrombosis, or indeed the other way round. Another potential bias could have been different presentation of the questionnaire to English-speaking and non-English-speaking patients. Furthermore, the interviews were conducted in the anticoagulation clinic, and it could be argued that a selection bias was inherent, as only the patients with insight and knowledge would be regular attenders. Most of the patients did indeed show a fair grasp of what their treatment entailed.

Nevertheless, this study is unique in that it looks at a cross-section of patients taking warfarin for various reasons.14,15 The findings are important for clinicians in highlighting a gap between what the patient knows and what the doctor thinks the patient knows. In a crowded outpatient clinic, the excuse for not explaining things is often lack of time; however, by encouraging patients to ask questions, by providing leaflets in their own native language, and by having them meet specialist nurses, most of the difficulties could be overcome. Also, regular audits and feedback are an effective way to make sure patients are fully involved in their own healthcare. Although our study did not show any statistically significant differences between the three ethnic groups with regard to overall knowledge, ethnicity does influence knowledge (and thus adherence).16,17,18,19

In the Indo-Asian communities, women and older people are most likely to leave their treatment in the hands of others rather than take responsibility for themselves.16,20 These individuals also tend to follow the doctor's advice without question and leave understanding of the illness and its implications, and responsibility for follow-up and treatment adherence, to other family members. In our paper on ethnic differences in perception of atrial fibrillation14 nearly half the patients from ethnic minority groups took warfarin ‘because their doctor told them to’, without knowing what good it might do. This observation was confirmed in the present study. Indo-Asians are reported to depend much on ‘faith’ or ‘God’ when ill,14,16 and this attitude could influence both adherence to treatment and the wish to be well informed about the illness and the medication.

Another reason for the patients' lack of knowledge concerning the disease process and the side-effects could, of course, be poor counselling and information-giving by healthcare professionals. Good communication between doctor and patient is particularly important in chronic medical conditions: patients who recall being counselled about adherence to therapies are better able to recall and adhere to the recommendations.21,22 In the present study, many Indo-Asian patients felt more comfortable with a doctor of the same ethnic group, possibly for language reasons but perhaps also because they would feel more at ease in asking questions. A sizeable proportion reported difficulty understanding what was said at the anticoagulant clinics, and those who perceived that they had no problems were almost thrice as likely to have a good knowledge score. But even in patients without language difficulties, the overall knowledge was suboptimal. As regards written material, Estrada et al.23 found that some of the patient information on anticoagulation therapy was above the comprehension level of most patients.

In conclusion, many of the patients attending anticoagulation clinics do not know what they are being anticoagulated for and have a poor idea of the complications. More investment in patient education is needed, with special emphasis on certain high-risk subgroups.


We acknowledge the support of the City Hospital Research and Development programme for the Haemostasis Thrombosis and Vascular Biology Unit.


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