Economic analyses of venous thromboembolism prevention strategies in hospitalized patients: a systematic review

Abstract

IntroductionDespite evidence-based guidelines for venous thromboembolism prevention, substantial variability is found in practice. Many economic evaluations of new drugs for thromboembolism prevention do not occur prospectively with efficacy studies and are sponsored by the manufacturers, raising the possibility of bias. We performed a systematic review of economic analyses of venous thromboembolism prevention in hospitalized patients to inform clinicians and policy makers about cost-effectiveness and the potential influence of sponsorship.MethodsWe searched MEDLINE, EMBASE, Cochrane Databases, ACP Journal Club, and Database of Abstracts of Reviews of Effects, from 1946 to September 2011. We extracted data on study characteristics, quality, costs, and efficacy.ResultsFrom 5,180 identified studies, 39 met eligibility and quality criteria. Each addressed pharmacologic prevention: low-molecular-weight heparins versus placebo (five), unfractionated heparin (12), warfarin (eight), one or another agents (five); fondaparinux versus enoxaparin (11); and rivaroxaban and dabigatran versus enoxaparin (two). Low-molecular-weight heparins were most economically attractive among most medical and surgical patients, whereas fondaparinux was favored for orthopedic patients. Fondaparinux was associated with increased bleeding events. Newer agents rivaroxaban and dabigatran may offer additional value. Of all economic evaluations, 64% were supported by manufacturers of a "new" agent. The new agent had a favorable outcome in 38 (97.4%) of 39 evaluations [95% confidence interval [CI] (86.5 to 99.9)]. Among studies supported by a pharmaceutical company, the sponsored medication was economically attractive in 24 (96.0%) of 25 [95% CI, 80.0 to 99.9)]. We could not detect a consistent bias in outcome based on sponsorship; however, only a minority of studies were unsponsored.ConclusionLow-molecular-weight heparins and fondaparinux are the most economically attractive drugs for venous thromboembolism prevention in hospitalized patients. Approximately two thirds of evaluations were supported by the manufacturer of the new agent; such drugs were likely to be reported as economically favorable.

When Are Statins Cost-Effective in Cardiovascular Prevention? A Systematic Review of Sponsorship Bias and Conclusions in Economic Evaluations of Statins

“…These results are consistent with other studies assessing the relationship between the source of funding and the cost-effectiveness findings, specifically for oncologic drugs [29–33], neuropsychiatric drugs [34–36], venous thromboembolism pharmacologic prevention [37], drug-eluting stents [38], bisphosphonates for osteoporosis treatment [39], Pap tests for cervical cancer diagnosis [40]. They are also consistent with the CEAs submitted by manufacturers to health technology assessment agencies [5,6], and/or reviews selecting general cost-effectiveness studies [4,7,41,42].…”

Economic evaluation of the prophylaxis for thromboembolism in critical care trial (E-PROTECT): study protocol for a randomized controlled trial

“…In order to determine such cost drivers, we performed a systematic review of economic analyses of thromboprophylaxis strategies in hospitalized patients to identify variables that we anticipate will drive costs and possible cost-effectiveness in E-PROTECT, and to determine potential ranges for willingness-to-pay to avoid DVT and PE [ 6 ]. From 5,180 potentially relevant studies, 39 met the eligibility criteria from which we extracted data on study characteristics, quality, costs and efficacy.…”

“…However, the manufacturer of the new agent supported approximately two-thirds of evaluations and such drugs were likely to be reported as economically favorable. Incremental cost-effectiveness ratios to prevent VTE events ranged from a dominance of LMWH to under $5,000 per VTE event avoided [ 6 ].…”

“…We have previously documented that most economic evaluations of VTE strategies are designed after the results of the trial are known, and are funded by the manufacturers of the agents compared [ 6 ]. This introduces the opportunity for biased design and interpretation of economic evaluations.…”

Evaluation of the use of low-molecular-weight heparin for venous thromboembolism prophylaxis in medical patients

“…For various reasons, low-molecular-weight heparin (LMWH) has largely replaced unfractionated heparin for pharmacological VTE prophylaxis. [11,12] It has proved to be safe [1,[13][14][15] and cost-effective and has been widely advocated [16][17][18][19][20] -a strategy that may also prove to have the unwanted consequence of overuse in low-risk patients. [21,22] In an effort to promote the safe and appropriate use of anticoagulants in VTE prophylaxis, both SA and the American College of Chest Physicians (ACCP) have published guidelines aimed at assisting clinicians in decision-making.…”