International standards for health economic evaluation with a focus on the German approach.

WHAT IS KNOWN AND OBJECTIVE: Health economic evaluation (HEE) is increasingly used in healthcare decision-making on the allocation of limited resources in national healthcare systems. Although the methods used for HEE vary in different countries, all economic evaluations address two questions: Are limited resources used optimally? Is value for money achieved in their use? Our objective is to explain some fundamental concepts in HEE and how these concepts are adapted in different countries, notably in Germany. METHODS: We performed a bibliographic search to identify existing methods of health economic evaluation of new drugs used by the official agencies of 11 countries (Austria, Australia, Canada, Finland, France, the Netherlands, Norway, New Zealand, Sweden, the United States and England and Wales) and compared them with that used by the German national agency IQWiG. RESULTS AND DISCUSSION: All countries considered follow internationally established standards of HEE. The majority of countries, including Germany, utilize primary outcome parameters such as disease-related morbidity and mortality for assessing relative efficacy and effectiveness. The most frequently recommended form of health economic evaluation is the cost-utility analysis (CUA). The German IQWIG is the only HTA body to use the cost-benefit concept of 'efficiency frontier' in its assessment. WHAT IS NEW AND CONCLUSION: While the core principles of HEE are the same worldwide, there is a lack of harmonization in the details. This requires resource-consuming adaptations in the analyses to meet different national requirements. We describe the core principles of HEE as a common basis for further discussions by all stakeholders.

Use of the relationship between blood lactate and running speed to determine the exercise intensity of horses.

Eight thoroughbred horses, trained for racing competition, were subjected to a standardised incremental speed test to determine the relationship between their blood lactate concentrations and running speed. Between 14 days before and 14 days after completing the standardised exercise test, the horses were timed for runs of 2000 to 6000 m. The blood lactate concentration after each run was measured and compared with the blood lactate concentration predicted from the individual horse's blood lactate-running speed relationship curve determined from the standardised exercise test. The relationship between the predicted and measured lactate concentrations was evaluated by linear regression. For 42 exercise runs there was a significant positive correlation between the measured and the predicted lactate concentrations and a significant regression: measured lactate (mmol/litre) = 1.01 predicted lactate (mmol/litre) -0.36 (r2 = 0.79, standard error of estimate 0-63 mmol/litre, P < 0.001). It was concluded that the standardised exercise test was a useful technique for predicting the blood lactate concentrations of horses after field exercise.

Reproducibility of the blood lactate-running speed curve in horses under field conditions.

OBJECTIVE: To examine the reproducibility of blood lactate-running speed curve parameters derived by a curve-fit equation and by linear interpolation from the results of 4-speed tests of sport horses under field conditions. DESIGN: Thoroughbreds completed 10 test pairs with 3 to 11 days between tests and retest. ANIMALS: 7 Thoroughbreds. PROCEDURE: The 4-speed test consisted of 4 runs over a distance of 2,110 m. Exercise intensity was increased by 1 m/s for each run. Blood lactate concentration measured after each run was plotted against running speed to determine the blood lactate-running speed relation. By means of the blood lactate-running speed relation, velocity inducing 2, 2.5, 3, 3.5, or 4 mM blood lactate concentration was calculated by a curve-fit equation and by linear interpolation. RESULTS: The test-retest correlation coefficient of velocity inducing 2, 2.5, 3, 3.5, and 4 mM blood lactate concentration determined by curve-fit equation was 0.67, 0.78, 0.84, 0.86, and 0.86, respectively, and by linear interpolation was 0.42, 0.58, 0.77, 0.87, and 0.78, respectively. But the test-retest regression was equal to the line of identity only for velocity inducing 3.5 and 4 mM blood lactate concentration. CONCLUSIONS: The reproducibility of velocity inducing 3.5 and 4 mM blood lactate concentration was sufficient to be used to compare horses and evaluate conditioning effects. This holds both methods of calculation of the parameters derived from the blood lactate-running speed relation.

[Intra-arterial fluorescein angiography using ophthalmic artery catheter in an experimental model]. / Intraarterielle Fluoreszenzangiographie mittels Arteria-ophthalmica-Katheter im Modell.

BACKGROUND: For the purpose of retinal angiography sodium fluorescein can be applied oral, intravenously or, via special catheters, intraarterially. In the latter procedure the imaging is different, which will be examined in this paper. There come up aspects, which supplement the possibilities of conventional sequence- or videoangiography and contrast the experimental technique of angiography by temperature-sensitive liposomes. MATERIAL AND METHODS: Intraarterial retinal angiography was carried out on 15 rabbits through a microcatheter and fluorescein was applied in different quantities and concentrations. RESULTS: Because of the direct inflow to the retina, the resulting images had more contrast and interference due to recirculating fluorescein was nearly excluded. With increased perfusion pressure, functional tests of circulation were possible. By administering small amounts of fluorescein 10% (0.01-0.02 ml/min) via the catheter, continuous perfusion provided continuous presentation of hemodynamics, by making visible retinal pulsation. CONCLUSIONS: The intraarterial fluorescence-angiography offers a new possibility for evaluating retinal circulation under increased pressure and for analysis of the retinal pulse wave. The procedure gets a clinical perspective by combined therapeutical application.

[Technique of selective, controlled retinal fibrinolysis in a model]. / Technik der selektiven, kontrollierten retinalen Fibrinolyse im Modell.

By microcatheterization of the ophthalmic artery it was possible to test a controlled retinal fibrinolysis in the rabbit. Heparin, tolazoline and urokinase were applied through the microcatheter. By continuous administration of highly diluted fluorescein (0.1%), on-line control of the therapeutic effects was available. Treatment was carried out in cycles of enforced perfusion. In 12 main vessel occlusions the rates of flow could nearly be normalized after mobilization of thrombi by combined emergency therapy. An average of 14 cycles of treatment was necessary. The time needed was 40-60 min. With this technique drug therapies of ocular circulation disturbances are testable and controlled emergency treatment of the eye begins to become feasible.