[Economic evaluation of health. Principles--example of laparoscopic cholecystectomy]

The objective of economic evaluation of health is to determine, for a given health action, the ratio between the investment involved and the results of this action. The basic principles of economic evaluation are presented. The author stresses that the concept of cost is a relative concept for a given observer, faced with a given decision or event and defining a space and temporal horizon of observation. Numerous methods are available to evaluate the results. Cost minimization studies compare two actions with an identical efficacy, cost-benefit studies assess the financial costs related to a health action, cost-efficacy studies relates costs to physical result indicators, and cost-usefulness studies attempt to integrate the relative value of a health action for a given observer. Economic evaluation increasingly attempts to take into account the quality of life and the patient's perception of the effects of a health action.