To the Editor: In their recent article on the use of modelling in pharmacoeconomics to estimate the potential benefits, risks and costs of preventive drugs, Liew and colleagues highlighted important strengths and limitations of this technique.1 One limitation is that modelling is discretionary: different analysts elect different models and get different answers. We argue that modelling is the first step. The next step is testing the predictive validity of the model by systematically collecting cost and effectiveness data over a period of time. Then the predictions of the original analysis could be compared to what actually transpired.
- 1. Liew D, McNeil JJ, Peeters A, et al. Epidemiological modelling (including economic modelling) and its role in preventive drug therapy. Med J Aust 2002; 177: 364-367. <eMJA full text>
- 2. Johnson K. Cost-effectiveness analysis: assessing the assumptions behind the assumptions. J Rheumatol 2000; 27: 1565-1567.
- 3. Kassirer J, Angell M. The Journal's policy on cost-effectiveness analyses. N Engl J Med 1994; 331: 669-670.
- 4. O'Brien B, Drummond M, Labelle R, Willan A. In search of power and significance: issues in the analysis of stochastic cost-effectiveness studies in health care. Med Care 1994; 32: 150-163.
- 5. Salkeld G, Mitchell A, Hill S. Pharmaceuticals. In: Mooney G, Scotton R, editors. Economics and Australian health policy. Sydney: Allen and Unwin, 1999: 115-136.
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K R J was a medical regulator for the United States Food and Drug Administration from 1985 to 2001, and now works for M-TAG, a private company that performs clinical, epidemiological and health economic evaluations of drugs, devices and technology.