Letters to the Editor
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Additional Letters to the Editor Available Online: Weighing the Risks and Benefits of Emergency
Contraception Joseph B. Stanford, M.D., Walter L. Larimore,
M.D., Discussion of Protective Effects of Hydrochlorothiazide Joel I. Wagman, M.D. |
Long-Term Standard-Dose Warfarin to Prevent Thrombosis
TO THE EDITOR: I read with interest the two-part article "DVT and Pulmonary Embolism"1,2 in American Family Physician, but would like to make a couple of corrections. Drs. Ramzi and Leeper state that a heart rate of less than 100 beats per minute merits a risk score of 1.5 in their adaptation of the Wells Clinical Prediction Rule for pulmonary embolus.1 In fact, tachycardia warrants a risk score of 1.5 points according to the Wells' Rule.3
In their discussion on the optimum International
Normalized Ratio (INR) at which to anticoagulate post-thromboembolism patients,
the authors recommend titrating warfarin (Coumadin) dosage to achieve an INR of
2.0 to 3.0 for a duration recommended by the American College of Chest
Physicians.2 This recommended minimum duration of
treatment varies from three to 12 months based on the risk of recurrence.
Referencing two studies4,5 the authors then state:
"Attempts have been made to maintain patients at an even lower INR (between
1.5 and 2.0), but results have been contradictory. Unless further data show
otherwise, anticoagulation with a standard INR goal of 2.0 to 3.0 should be
used."2 This statement requires some clarification.
The studies referenced4,5 do not contradict standard
warfarin protocol or suggest an amendment to the initial long-term
anticoagulation management of venous thromboembolism mentioned in the article.
The patients in both studies had already completed at least three months of
conventional-dose (INR = 2.0 to 3.0) anticoagulation before being randomized to
their respective treatment arms.
Ridker and colleagues4 demonstrated in a placebo-controlled trial that long-term (mean duration 2.1 years) low-intensity (INR = 1.5 to 2.0) warfarin therapy resulted in a large and significant reduction in the risk of recurrent venous thromboembolism with little evidence of increased risk of major hemorrhage or stroke. They conclude that long-term low-intensity anticoagulation is a highly effective method of preventing recurrent venous thromboembolism. Thus, one might infer that continued low-intensity long-term anticoagulation after an initial period of full-dose anticoagulation is superior to full-dose anticoagulation that is halted after three to 12 months.
Kearon and colleagues5 demonstrated that long-term (mean duration 2.4 years) low-intensity warfarin was significantly less effective than conventional-dose warfarin for the prevention of recurrent venous thromboembolism, and that low-intensity warfarin does not reduce the risk of clinically significant bleeding. They conclude that the intensity of anticoagulation therapy should not be lowered after three months of treatment and that long-term conventional-intensity warfarin therapy is highly effective in prevention of recurrent thrombosis and is associated with a low frequency of bleeding.
Ridker4 and Kearon and colleagues5 therefore agree that warfarin therapy for at least two years in patients with a history of idiopathic venous thromboembolism reduces the rate of recurrence without significantly increasing the risk of major bleeding, with Kearon and colleagues finding greater efficacy and no added risk using the conventional dose.
REFERENCES
1. Ramzi DM, Leeper KV. DVT and pulmonary embolism: part I. Diagnosis [published correction appears in Am Fam Physician 2004;70:1455]. Am Fam Physician 2004;69:2829-36.
2. Ramzi DM, Leeper KV. DVT and pulmonary embolism: part II. Treatment and prevention. Am Fam Physician 2004;69:2841-8.
3. Fdullo PF, Tapson VF. The evaluation of suspected pulmonary embolism. N Engl J Med 2003;349:1247-56.
4. Ridker PM, Goldhaber SZ, Danielson E, et al. Long-term, low-intensity warfarin therapy for the prevention of recurrent venous thromboembolism. N Engl J Med 2003;348:1425-34.
5. Kearon C, Ginsberg JS, Kovacs MJ, Anderson DR, Wells P, Julian JA, et al. Comparison of low-intensity warfarin therapy with conventional-intensity warfarin therapy for long-term prevention of recurrent venous thromboembolism. N Engl J Med 2003;349:631-9.
The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U.S. Army Medical Department or the U.S. Army Service at large.
editor's note: This letter was sent to the authors of "DVT and Pulmonary Embolism: Part I. Diagnosis," who declined to reply.
Imiquimod to Treat Basal Cell and Squamous Cell Carcinomas
TO THE EDITOR: It was good to see the review article1 of basal cell and squamous cell carcinomas. Please note that, since this article was written, imiquimod 5% cream (Aldara) has received approval by the U.S. Food and Drug Administration for the treatment of some types of actinic keratoses and basal cell cancers. It is specifically indicated for the treatment of biopsy-confirmed, primary superficial basal cell carcinoma in immunocompetent adults, with a maximum tumor diameter of 2 cm.2
REFERENCES
1. Stulberg DL, Crandell B, Fawcett RS. Diagnosis and treatment of basal cell and squamous cell carcinomas. Am Fam Physician 2004;70:1481-8.
2. Aldara [package insert]. St. Paul, Minn.: 3M Pharmaceuticals, 2004.
editor's note: 3M Pharmaceuticals manufactures imiquimod.
The article "Mildly Elevated Liver Transaminase Levels in the Asymptomatic Patient" (March 15, 2005, page 1105) contained an error in the ratio of aspartate transaminase (AST) to alanine transaminase (ALT). In several locations throughout the text, namely on pages 1106, 1107, in the Strength of Recommendations (SOR) table on page 1106, and in Table 3 on page 1108, the ratio was incorrectly listed as the ratio of ALT to AST. The correct ratio is AST to ALT. The corrected SOR table and Table 3 are reprinted below. The online version of this article has been corrected.
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Strength of Recommendations |
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Key clinical recommendation |
Label |
References |
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An algorithmic approach to evaluating mildly abnormal liver functions is recommended. |
C |
1 |
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In the asymptomatic patient with negative
serum testing and mild transaminase elevations, a |
C |
1 |
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If abnormalities persist at the six-month follow-up visit, an ultrasonography of the liver is the recommended imaging modality. |
C |
1 |
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ALT and AST are not useful screening tests in an otherwise healthy population. |
C |
1, 10 |
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The AST/ALT ratio is only somewhat helpful in diagnosis. |
C |
5, 7 |
| ALT = alanine transaminase; AST = aspartate transaminase. A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, opinion, or case series. |
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Table 3 Clues in the Evaluation of Mildly Elevated Liver Transaminase Levels |
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Clinical clue |
Suggested diagnosis |
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Longstanding alcohol abuse |
Cirrhosis |
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Intravenous drug use, history of blood product transfusions, nonsterile needle exposure, AST/ALT ratio < 1.0 |
Hepatitis B or C |
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Obesity, diabetes, hyperlipidemia, AST/ALT ratio < 1.0 |
Steatosis/steatohepatitis |
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AST/ALT ratio > 2.0 |
Alcoholic liver disease, |
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Increased iron levels |
Hemochromatosis |
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Polypharmacy, illicit drug use, or certain herbal supplement use |
Substance/ medication-induced |
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Frequent, strenuous exercise |
Exercise-induced |
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Intestinal bloating; oily, bulky stools |
Celiac sprue |
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Hypergammaglobulinemia |
Autoimmune hepatitis |
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Reduced ceruloplasmin levels, Kayser-Fleischer ring |
Wilson's disease |
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Depressed thyroid-stimulating hormone levels |
Hyperthyroidism |
| ALT = alanine transaminase; AST = aspartate transaminase. |
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Send letters to Jay Siwek, M.D., Editor, American Family Physician, 11400 Tomahawk Creek Pkwy., Leawood, KS 66211-2672; fax: 913-906-6080; e-mail: afplet@aafp.org.
Please include your complete address, telephone number, fax number, and e-mail address. Letters should be submitted on disk, double-spaced, fewer than 500 words, and limited to one table or figure and six references. Please submit a word count.
Letters submitted for publication in AFP must not be submitted to any other publication. Possible conflicts of interest must be disclosed at time of submission. Submission of a letter will be construed as granting the AAFP permission to publish the letter in any of its publications in any form. The editors may edit letters to meet style and space requirements.
| Copyright © 2005 by the American
Academy of Family Physicians. |
