Cost effectiveness, the economic considerations of prenatal screening strategies for trisomy 21 in the Czech Republic.

OBJECTIVES: To perform an incremental cost-effectiveness analysis for screening of trisomy 21 (Down syndrome) in the Czech Republic through a decision tree model designed to evaluate the costs and potential risks involved in using different strategies of screening. METHODS AND DATA ANALYSIS: Using decision-analysis modelling, we compared the cost-effectiveness of nine possible screening strategies for trisomy 21: 1. maternal age > or = 35 in first trimester, 2. maternal age > or = 35 in second trimester, 3. second trimester triple test (AFP, hCG, mu E3), 4. nuchal translucency measurement, 5. first trimester serum test (PAPP-A, fbeta-hCG), 6. first trimester combined (nuchal translucency, PAPP-A, fbeta-hCG) not in OSCAR manner, 7. first trimester combined (nuchal translucency, PAPP-A, fbeta-hCG) in OSCAR manner, 8. first trimester combined (nuchal translucency, nasal bone, PAPP-A, fbeta-hCG) not in OSCAR manner, 9. first trimester combined (nuchal translucency, nasal bone, PAPP-A, fbeta-hCG) in OSCAR manner. The analysis is performed from a health care payer perspective using relevant cost and outcomes related to each screening strategy in a cohort of 118,135 pregnant women presenting around 12 weeks of pregnancy in the Czech Republic. Using a computer spreadsheet Excel (Microsoft Corporation, Redmond, Wash) the following outcomes: overall cost-effectiveness, trisomy 21 cases detected, trisomy 21 live birth prevented and euploid losses from invasive procedures were obtained. The incremental cost-effectiveness ratios were also calculated by a comparison of strategy nine and strategy three (the current practice in the Czech Republic).

RESULTS: Under the baseline assumptions, the model favors strategy nine as the most cost-effective trisomy 21 screening strategy. This strategy was the least expensive strategy per trisomy 21 cases averted. Although all the other strategies cost less, they all had lower trisomy 21 detection rates and higher numbers of procedure-related losses (except for strategies six and seven, which had same loss rate) compared with strategy nine. All strategies considered were cheaper compared with screening only by maternal age over 35 years. Adding the nasal bone and the OSCAR manner made strategy nine the most cost-effective one. The incremental cost-effectiveness (cost per additional trisomy 21 case prevented) comparing strategy nine and second trimester triple test (current practice in Czech Republic) yielded an additional baseline cost of 219,326 CZK. This would seem not to save money but due to the low false positive rate the test is less costly than might be expected and it is more cost-effective than the current practice in the Czech Republic (3,580,082 CZK for the current practice and 2,469,833 CZK for our strategy in terms of costs per DS case prevented).

CONCLUSION: In our analysis the NT, NB, PAPP-A and fbeta-hCG combined test carried out in the first trimester was the most cost-effective screening strategy for trisomy 21 in the Czech Republic.