The use of oral anticoagulant therapy (OAT) to prevent thromboembolism has been widespread in recent years. The concept of high- and low-intensity regimens has facilitated treatment for many, and has lowered the hazards of overly intense anticoagulation. However, a significant proportion of patients suited to the low intensity regimen are not being treated. It is not clear whether its wider use is limited by continued debate, lack of resources, lack of expertise, or other causes. We retrospectively reviewed the medical records of 32 patients treated with OAT administered in the primary care setting. The average age was 66 ± 11 years (range 34-84). 9 were treated with high-intensity OAT: 8 due to artificial heart valves, and 1 due to a hypercoagulable syndrome with recurrent thromboembolis, 23 were treated with low-intensity OAT, 17 of whom had atrial fibrillation. 11 were also being treated continuously with other medications which interacted with OAT or interfered with other coagulation pathways. Such medication included: aspirin, dipyridamole, amiodarone, bezafibrate and allopurinol. Of 414 coagulation tests, 57% and 65% were in the therapeutic range in the high- and low-intensity OAT groups, respectively. There was no major bleeding event, but in 2 of 8 who bled, gastrointestinal bleeding led to hospitalization. Treatment was discontinued in 1 patient because of difficulties in achieving target INR, and in the 2 hospitalized for bleeding. The percentages of test results in, above and below the therapeutic range were similar to those in other large series, for both intensity regimens. We found that a significant proportion of patients were under chronic treatment with other medication which interacted with OAT. To estimate the rate of complications in primary care OAT, larger series are needed. We conclude that OAT can be given and monitored by the family physician, and that awareness of long and short term drug interactions with OAT is mandatory.
|Published - 1 Jun 1997