Anticoagulation for patients with atrial fibrillation

Editor—Connolly's view that Kalra et al's findings clearly show that the results of anticoagulation studies can be replicated in general medical practice may be an overinterpretation of the data.1,2 The 167 patients in the study may not have been a representative sample of high risk patients found in general practice. Patients were recruited from secondary care medical clinics, not general practice, and bias in the study group could have been introduced by selection for hospital referral. Furthermore, bias could have occurred by exclusion of those high risk patients who were already taking warfarin, who may have been considered by their general practitioner to have been at a lower risk of haemorrrhagic complications or a greater risk of stroke. Knowledge of the outcome of the 76 patients already taking warfarin, who presumably were being managed by the same anticoagulation service as trial patients, is also required. The most striking finding from Kalra et al's study was that 167 of 172 (97%) high risk patients agreed to warfarin treatment. Knowledge of how this level of acceptance was achieved would be useful for clinical practice. Howitt and Armstrong found that after patients in general practice were educated about stroke, given detailed information about aspirin and warfarin, and shown a pictorial representation of risk and expected benefits of treatment only 10 of 56 patients started warfarin, 20 declined treatment, one changed from warfarin to aspirin, and the remainder continued to take warfarin.3 In contrast, Sudlow et al found that 78% of women and 93% of men aged 75 and over, the majority of whom were at high risk, would take a tablet (warfarin) to prevent stroke, but patients were only told the overall benefits of treatment and not told specifically about risks.4 Acceptance of treatment declined if anticoagulation monitoring was carried out at the hospital or general practitioner's surgery. The same group has also highlighted the factors influencing general practitioners' use of warfarin and did not find that warfarin was considered too expensive to manage in primary care and willingness to use it could be encouraged by further remuneration.5 Maybe it is not crucial to educate doctors about the benefits of warfarin, but perhaps the key to increasing its use in high risk patients is to adopt Kalra et al's approach to discussing “warfarinisation,” whatever that is, deliver the monitoring service in the patient's home, and remunerate general practitioners adequately for supervising the treatment and screening patients to identify those who would be eligible for treatment.