Article type
Year
Abstract
Introduction: The health economics literature grew steadily during the last decades, making a significant number of cost-benefit and cost-effectiveness studies available to clinicians and policy makers. Many decisions could now be taken on the basis of evidence on the efficiency, as well as effectiveness, of alternative courses of action, drawn from economic studies. However, such information is often contained in several and possibly conflicting reports, and rigorous methods for pooling cost estimates are increasingly needed.
Objective: To review costing methodologies adopted in economic evaluation of health care interventions; assess the consistency of cost structure from different reports, and whether reported figures serve adequately the objectives of economic studies; devise techniques for reducing the heterogeneity of cost estimates and pooling them into single values for supporting decision making processes.
Methods: An existing systematic review of economic evaluation of vaccination against hepatitis B provided a significant number of studies (90) for exploring the consistency of costing methodologies. Studies were collected by means of searches on literature databases, manual searches of selected journals, and direct contacts with the authors of retrieved studies. Methods for calculating direct and indirect costs, when reported, were assessed separately, and without blinding, by two of the authors. Intangible costs were neglected.
Results: High heterogeneity of costing methodologies was found in the sample of economic evaluation. In some cases, costs were simply taken from literature sources. Sometimes charges were used. In other cases, original estimates were explicitly devised, but using disparate cost structures (variable/full costs, marginal/average costs). No stochastic cost analysis was available. Moreover, differences among studies were increased by variability in the object of cost analysis (different types of hepatitis B cases were considered). Finally, the country of origin, the study-setting, and characteristics of the health care system were found to influence significantly cost estimates. Special techniques have been developed for overcoming, at least in part, such heterogeneity, and to pool cost values.
Discussion: The comparability of cost estimates drawn from different economic evaluations is restricted by the theoretical and empirical constraints. The information on resource use and costs available from published articles is often insufficient for reducing the level of heterogeneity and attempting to pool estimates. However, decisions made in health systems need to be informed by appropriate syntheses of economic studies, and cost figures reported from different studies should be reviewed systematically and, whenever possible, pooled.
Objective: To review costing methodologies adopted in economic evaluation of health care interventions; assess the consistency of cost structure from different reports, and whether reported figures serve adequately the objectives of economic studies; devise techniques for reducing the heterogeneity of cost estimates and pooling them into single values for supporting decision making processes.
Methods: An existing systematic review of economic evaluation of vaccination against hepatitis B provided a significant number of studies (90) for exploring the consistency of costing methodologies. Studies were collected by means of searches on literature databases, manual searches of selected journals, and direct contacts with the authors of retrieved studies. Methods for calculating direct and indirect costs, when reported, were assessed separately, and without blinding, by two of the authors. Intangible costs were neglected.
Results: High heterogeneity of costing methodologies was found in the sample of economic evaluation. In some cases, costs were simply taken from literature sources. Sometimes charges were used. In other cases, original estimates were explicitly devised, but using disparate cost structures (variable/full costs, marginal/average costs). No stochastic cost analysis was available. Moreover, differences among studies were increased by variability in the object of cost analysis (different types of hepatitis B cases were considered). Finally, the country of origin, the study-setting, and characteristics of the health care system were found to influence significantly cost estimates. Special techniques have been developed for overcoming, at least in part, such heterogeneity, and to pool cost values.
Discussion: The comparability of cost estimates drawn from different economic evaluations is restricted by the theoretical and empirical constraints. The information on resource use and costs available from published articles is often insufficient for reducing the level of heterogeneity and attempting to pool estimates. However, decisions made in health systems need to be informed by appropriate syntheses of economic studies, and cost figures reported from different studies should be reviewed systematically and, whenever possible, pooled.