Strengths and limitations
The strengths of this study are inclusion of a large cohort of
pregnancies with retrospective application of the FMF algorithm. This
allowed for the input of actual data, such as physician compliance with
aspirin prophylaxis, into the model structure and probabilities for the
cost analysis.
Due to the retrospective application of the FMF algorithm, a proportion
of those who were screen positive using the FMF algorithm received
aspirin. Therefore, a limitation of this study was that the input data
had to be estimated in this group adjusting for the possible effect of
aspirin. However, as we have only considered the effect of the
intervention on preterm, rather than total PE, of which a possible
benefit has been demonstrated22, our estimates of
cost-savings can only represent an under-estimate.
Finally, neither PLGF or UtA-PI were incorporated into the FMF algorithm
in our study. Through clinical effectiveness studies, incorporation of
these biomarkers would only improve the performance of the screening
method and, therefore, an even greater reduction in the rate of preterm
PE could be anticipated. Again, this emphasises the conservative
approach adopted in this study to avoid an inflation in the expected
cost-savings.8, 23