Cost effectiveness of desirudin compared with a low molecular weight heparin in the prevention of deep vein thrombosis after total hip replacement surgery

Hirudin in the Treatment of Chronic Kidney Disease

Chronic kidney disease (CKD) is a common public health concern. The global burden of CKD is increasing due to the high morbidity and mortality associated with it, indicating the shortcomings of therapeutic drugs at present. Renal fibrosis is the common pathology of CKD, which is characterized by glomerulosclerosis, renal tubular atrophy, and renal interstitial fibrosis. Natural hirudin is an active ingredient extracted from Hirudo medicinalis, which has been found to be the strongest natural specific inhibitor of thrombin. Evidence based on pharmacological data has shown that hirudin has important protective effects in CKD against diabetic nephrology, nephrotic syndrome, and renal interstitial fibrosis. The mechanisms of hirudin in treating CKD are mainly related to inhibiting the inflammatory response, preventing apoptosis of intrinsic renal cells, and inhibiting the interactions between thrombin and protease-activated receptors. In this review, we summarize the function and beneficial properties of hirudin for the treatment of CKD, and its underlying mechanisms.

Pharmacological Activities and Mechanisms of Hirudin and Its Derivatives - A Review

Hirudin, an acidic polypeptide secreted by the salivary glands of Hirudo medicinalis (also known as "Shuizhi" in traditional Chinese medicine), is the strongest natural specific inhibitor of thrombin found so far. Hirudin has been demonstrated to possess potent anti-thrombotic effect in previous studies. Recently, increasing researches have focused on the anti-thrombotic activity of the derivatives of hirudin, mainly because these derivatives have stronger antithrombotic activity and lower bleeding risk. Additionally, various bioactivities of hirudin have been reported as well, including wound repair effect, anti-fibrosis effect, effect on diabetic complications, anti-tumor effect, anti-hyperuricemia effect, effect on cerebral hemorrhage, and others. Therefore, by collecting and summarizing publications from the recent two decades, the pharmacological activities, pharmacokinetics, novel preparations and derivatives, as well as toxicity of hirudin were systematically reviewed in this paper. In addition, the clinical application, the underlying mechanisms of pharmacological effects, the dose-effect relationship, and the development potential in new drug research of hirudin were discussed on the purpose of providing new ideas for application of hirudin in treating related diseases.

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

Introduction

Despite 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.

Methods

We 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.

Results

From 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.

Conclusion

Low-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.

Desirudin dosing and monitoring in moderate renal impairment

Desirudin is a renally eliminated direct thrombin inhibitor approved to prevent venous thromboembolism. Empiric dosage adjustment and activated partial thromboplastin time (aPTT) monitoring in patients with moderate renal impairment are recommended, but supportive data are lacking. The objective of this study was to evaluate appropriate desirudin dosing in moderate renal impairment and the effect of desirudin on aPTT in moderate renal impairment. Desirudin plasma concentration and aPTT data were extracted from 6 studies. Participants with normal renal function or moderate renal impairment (creatinine clearance [ClCr] 31-60 mL/min) were included. Pharmacokinetic and Monte Carlo simulations were done. After administration of desirudin 15 mg every 12 hours subcutaneously (SC) to steady state, peak desirudin concentrations were 35 and 47 nmol/L in the normal and moderate renal function groups, respectively. Monte Carlo simulations found median 2-hour C(max) concentrations of 51.7 nmol/L in normal renal function and 52.4 nmol/L in moderate renal impairment. Desirudin exhibits a linear relationship when the square root of desirudin concentration is plotted versus the aPTT ratio (r(2) = 0.76). These analyses support the dosing of desirudin at 15 mg every 12 hours SC without aPTT monitoring in patients with moderate renal impairment.

The long-term cost-effectiveness of fetal monitoring during labour: a comparison of cardiotocography complemented with ST analysis versus cardiotocography alone

Objective

To assess the cost-effectiveness of the use of cardiotocography (CTG) complemented with fetal electrocardiography and ST analysis compared with the use of CTG alone in term deliveries when a decision has been made to use fetal monitoring with a scalp electrode.

Design

A cost-effectiveness analysis based on a probabilistic decision model incorporating relevant strategies and lifelong outcomes.

Setting

Maternity wards in Sweden.

Population

Women with term fetuses after a clinical decision had been made to apply a fetal scalp electrode for internal CTG.

Methods

A decision model was used to compare the costs and effects of two different treatment strategies. Baseline estimates were derived from the literature. Discounted costs and quality-adjusted life years (QALYs) were simulated over a lifetime horizon using a probabilistic model.

Main outcome measures

QALYs, incremental costs, and cost per QALY gained expressed as incremental cost-effectiveness ratio (ICER).

Results

The analysis found an incremental effect of 0.005 QALYs for ST analysis compared with CTG; the ST analysis strategy was also moreover associated with a €56 decrease in costs, thus dominating the CTG strategy. The probability that ST analysis is cost-effective in comparison with CTG is high, irrespective of the willingness-to-pay value for a QALY.

Conclusions

Compared with CTG alone, ST analysis is cost-effective when used in term high-risk deliveries in which there is a need for internal fetal monitoring.

Cost-effectiveness of venous thromboembolism prophylaxis in total hip and knee replacement surgery: the evolving application of health economic modelling over 20 years

OBJECTIVES

In the last two decades, there has been considerable evolution of methods for cost-effectiveness modelling. Some of the first models were developed in the area of venous thromboembolism (VTE) prophylaxis. Hence, this area can serve as an important example to illustrate evolving standards. Our objectives are to document evolving methodology by describing VTE models, assess their critical strengths and weaknesses, and inform future advances for models in this therapeutic area.

RESEARCH DESIGN AND METHODS

A systematic review of economic models of primary VTE prevention following hip and knee replacement surgery was undertaken. Electronic searches of PubMed, EMBASE, the Cochrane library, and grey literature were conducted (1985-2006). Reference lists of included articles and reviews were examined for relevant studies.

RESULTS

Twenty-nine cost-effectiveness models were identified. Nineteen other cost-effectiveness analyses were excluded because they were not model-based; 16 were simple cost calculations and three were analyses of resource use data collected alongside clinical trials. The majority of models (24) were constructed as decision trees, frequently utilising previously published model structures, with some adaptation for new comparators, and/or addition of relevant events omitted by earlier models (e.g., bleeding due to prophylactic treatment). Later models have included Markov processes to model potential long-term consequences of VTE (recurrent VTE and post-thrombotic syndrome) over longer time horizons. Systematic identification of clinical evidence and more sophisticated analysis methods (e.g., Bayesian mixed-treatment comparisons and probabilistic sensitivity analyses) have recently been introduced.

CONCLUSIONS

Model structures have evolved substantially in this highly studied therapeutic area, with improvements made to the model structure, the comprehensiveness of clinical evidence included, and the underlying calculation methodology.

Cost-effectiveness of extended prophylaxis with fondaparinux compared with low molecular weight heparin against venous thromboembolism in patients undergoing hip fracture surgery

A model was developed to estimate costs and clinical effectiveness of fondaparinux compared with enoxaparin after hip fracture surgery in Sweden. Outcomes and costs of venous thromboembolism (VTE)-related care from a health care perspective were incorporated, with symptomatic deep-vein thrombosis and pulmonary embolism, recurrent VTE, post-thrombotic syndrome, major haemorrhage and all-cause death being included. Event probabilities were derived from fondaparinux clinical trial data and published data. VTE-related resource use and associated costs as well as costs of prophylaxis were based on local Swedish data. Extended prophylaxis with fondaparinux could avoid an additional 28 symptomatic VTE per 1,000 patients compared with extended prophylaxis with enoxaparin in hip fracture surgery patients. Although the prophylaxis costs were higher in the fondaparinux group, these were offset by the lower costs associated with treating fewer VTE, which thus indicates that extended fondaparinux prophylaxis is the dominant alternative when compared with enoxaparin in hip fracture surgery.

Pharmacoeconomic considerations in anticoagulant drug use

Anticoagulants are used for the prevention and treatment of venous thromboembolism and for the secondary prevention of stroke and myocardial infarction. The list of available anticoagulants includes unfractionated heparin, low molecular weight heparins, fondaparinux, warfarin and the direct thrombin inhibitors. Numerous randomised controlled trials have pitted one anticoagulant against another to ascertain superiority in terms of safety and efficacy. Differences in these outcomes are assessed using appropriate statistical tests. When a statistically significant difference is found, it is generally accepted that one option is superior to another. There is also an interest in whether there is a clinically significant difference between two or more treatments, even when there may not be a statistically significant difference. This decision is reached through clinical judgment based on logical and ethical considerations. Another important way to judge the difference between alternative treatment strategies is to test for economically significant differences. This is accomplished through pharmacoeconomic analysis. This paper reviews the evidence gathered from published studies designed to detect an economically significant difference between two or more anticoagulants used for the same clinical indication.

A systematic review of economic analyses of low-molecular-weight heparin for the treatment of venous thromboembolism

INTRODUCTION

Public concerns about the increase in health care expenditure have prompted investigators to analyze the costs and benefits of health care interventions. We conducted a systematic review of economic analyses of venous thromboembolism treatment focusing on studies evaluating low-molecular-weight heparin.

MATERIALS AND METHODS

We identified studies by a MEDLINE search and a review of bibliographies of retrieved articles. From each eligible study, we extracted data on the study characteristics, the effectiveness, and the cost of managing the venous thromboembolism with respect to treatment. We critically appraised the studies according to the framework from the Users' Guides to the Medical Literature XIII: How to Use an Article on Economic Analysis of Clinical Practice.

RESULTS

Six of these eight economic analyses of venous thromboembolism treatment that met the inclusion criteria for this review showed that low-molecular-weight heparin is associated with less recurrent venous thromboembolism and is less costly than treatment with unfractionated heparin. Although discrete recurrent venous thromboembolism event rates were not included in the seventh study, these investigators concluded that the cost of low-molecular-weight heparin for the treatment of venous thromboembolism treatment was offset by the savings associated with fewer hospital admissions when low-molecular-weight heparin was used. In the eighth study, although the cost of treatment with low-molecular-weight heparin was higher than treatment with unfractionated heparin, the investigators concluded that low-molecular-weight heparin is cost-effective for inpatient management.

CONCLUSIONS

Low-molecular-weight heparin treatment may confer economic advantages over unfractionated heparin therapy because it does not require anticoagulant monitoring and it facilitates outpatient therapy.