Low-molecular-weight heparin more cost-effective than unfractionated heparin for preventing blood clots in critically ill patients

From a health care payer perspective, prevention of venous thromboembolism (blood clot in a vein) with low-molecular-weight heparin dalteparin in critically ill patients was more effective and had similar or lower costs than the use of unfractionated heparin, according to a study appearing in JAMA. The study is being released to coincide with its presentation at the Critical Care Canada Forum.

A recent randomized trial (PROTECT) comparing the effectiveness of the two most common strategies using drugs to prevent venous thromboembolism (VTE), the anticoagulants low-molecular-weight heparin (LMWH) dalteparin and unfractionated heparin (UFH), found no difference regarding deep-vein thrombosis but reduced rates of pulmonary embolus (clot) and heparin-induced thrombocytopenia (low platelet count) in the patients who received LMWH dalteparin. Drug acquisition costs have historically been higher for LMWH than for UFH. However, if the effects of these drugs on outcomes important to patients differs substantially, paying more may be worth it, which highlights the need for comparative economic and clinical effectiveness research to inform practice, according to background information in the article. Cost is cited as the most important barrier to using LWMH in a recent North American survey.

Robert A. Fowler, M.D.C.M., M.S., of the Sunnybrook Health Sciences Centre, University of Toronto, and colleagues evaluated the comparative cost-effectiveness of LMWH vs UFH for prevention against VTE in critically ill patients. The researchers conducted an economic evaluation concurrent with the PROTECT trial (May 2006 to June 2010), including measured costs among 2,344 patients in 23 centers in 5 countries and applied these costs to measured resource use and effects of all enrolled patients.

The researchers found that the median postrandomization hospital costs of care for patients who received UFH was greater ($40,805) compared with $39,508 for patients who received dalteparin, but the difference was not statistically significant. For 7 of 8 prespecified subgroups, using conventional cost metrics to prevent specific VTE-related events indicated that dalteparin was the most effective and least costly strategy to prevent all thrombotic events, pulmonary embolus, deep-vein thrombosis, major bleeding, and heparin-induced thrombocytopenia, given its lower cost combined with better effects.

Additional analyses indicated that a strategy using LMWH was most effective, least costly 78 percent of the time, and remained least costly unless the drug acquisition cost of dalteparin was to increase by more than 20-fold. There was no threshold in which lowering the acquisition cost of UFH favored prevention with UFH.

"These findings are important for the care of critically ill patients because they provide a cost-minimization rationale that complements clinical effectiveness knowledge from PROTECT. For example, if an ICU with 1,000 medical-surgical admissions per year uses UFH instead of LMWH for prevention of VTE, the annual incremental cost may be between $1,000,000 to $1,500,000 with similar or worse clinical outcomes, despite the individual drug cost of UFH being $4 to $5 less per day," the researchers write.

The authors note that these findings were driven by lower rates of pulmonary embolus and heparin-induced thrombocytopenia and corresponding lower overall use of resources with LMWH.