Date and Time
April 9, 2008
1:30 PM - 3:00 PM

Availability
Open to the public
No RSVP required

Speaker
Lynn B. Davis - Stanford University

Objective: Cystic fibrosis (CF) is the most common fatal autosomal recessive disease among Caucasians, with an average life expectancy of less than 40 years of age. Preimplantation genetic diagnosis (PGD) may prevent the birth of a CF-affected child without the emotional and physical burden of aborting a desired pregnancy at a late gestation. The objective of this study was to perform a cost-benefit analysis of PGD for carrier couples of CF compared to the alternative of natural conception (NC) followed by prenatal testing and subsequent termination of affected pregnancies.

Design: Cost-benefit analysis.

Materials and Methods: A Markov model was created using TreeAge Pro Software. A cohort of 10,000 female patients was run through the NC and PGD branches. The model reflected the perspective of an actuarially fair insurer who considers all costs and benefits to society. Only direct costs and benefits were used. Indirect costs and benefits such as the emotional and physical burden of abortion and patient preference for or against twins are not easily quantifiable and as such were not included in this study. Applying the standard human capital method, we calculated the net benefit of giving birth to a child as the present value of lifetime earnings minus lifetime medical costs.

Results: For women younger than 35 years of age, the net benefit of PGD over NC was $264,000 ($872,000-$608,000 respectively). For women aged 35-39, the net benefit of PGD over NC was $214,000 ($808,000-$594,000 respectively). For women older than 40 years of age, the net benefit of PGD over NC was $141,000 ($650,000-$509,000 respectively). For all women who tested positive for a CF fetus, at an abortion rate of 100% (base case), there were 2,850 abortions in the NC group compared with 30 in the PGD group.

Conclusions: PGD provides substantial net benefits relative to NC, regardless of maternal age. The model results were sensitive to the probability of elective abortion of an affected fetus and the probability of giving birth to twins, but changed little with variation in other parameter values. These results apply when the patient is certain she would abort an affected fetus, and become even more cost-beneficial for women who are uncertain about abortion or decide to forgo it. NC provides greater benefits than PGD only when the indirect costs of twins exceed the net benefit of a single child. Carrier couples of cystic fibrosis should be offered PGD for prevention of an affected child.