My student and I have read the above article with much interest. It has led to much research this afternoon and reading of the American College of Chest Physicians (ACCP) 2012 guidelines for confirmation of some of the statements within the article. We would like to point out 2 items.
The first point is a typo: on page 134, in discussing the exclusion criteria, we believe the authors meant to say less than (<)18 years, but the symbol used was the greater than sign (>18), inferring that the study was conducted on pediatric patients only.
Second, I challenge the authors that the 2012 guidelines do not suggest as far as I can find, that low-molecular-weight heparin (LMWH) should be used as monotherapy for 6 months. Their suggestion is for 3 months.
Mallory Johnson, PharmD candidate
Pamela C. Evans, PharmD
St. Dominic-Jackson Memorial Hospital
Thank you for your interest in this study. Your first point is correct. This was a typo. This study was not conducted with pediatric patients. The results of the study illustrate that the study population was aged 22 to 89 years (mean age, 66 years). The study was not intended to cover only patients under age 18.
Second, we did not intend to imply that the 2012 ACCP guidelines suggest LMWH monotherapy for 6 months. These guidelines recommend extended anticoagulant therapy over 3 months (Grade 1B). The 2012 ACCP guidelines were referenced in the “background” section of the article, because they are the most current guidelines for venous thromboembolism (VTE) therapy. In the background, we did not discuss a specific duration of therapy, but simply stated that the use of LMWH as an extended anticoagulant therapy is preferred over vitamin K antagonist therapy for the treatment of VTE in patients with cancer. At the time our study was conducted, the 2008 ACCP guidelines were the most recent guidelines published by the ACCP, and they are referenced in the “methods” section of the article. The 2008 ACCP guidelines recommend LMWH for the first 3 to 6 months of long-term anticoagulant therapy (Grade 1A). The duration of 6 months is specifically preferred in the 2007 American Society of Clinical Oncology and the 2010 National Comprehensive Cancer Network guidelines, which are also referenced in the article and were the most recent guidelines published by these organizations at the time the study was conducted. In addition, the CLOT trial, which demonstrated the superiority of LMWH over warfarin, used the 6-month duration of LMWH monotherapy within its study design. We regret any confusion.