Universal Fetal Echocardiography for Pregestational Diabetes Mellitus

Abstract

OBJECTIVE: To evaluate the cost effectiveness of universal fetal echocardiogram for patients with pregestational diabetes mellitus by first-trimester hemoglobin A1c (Hb A1c) level. METHODS: We developed a cost-effectiveness model comparing two strategies of screening for critical fetal congenital heart disease among patients with diabetes: universal fetal echocardiogram and fetal echocardiogram only after abnormal findings on detailed anatomy ultrasonogram. We excluded ventricular septal defect, atrial septal defects, and bicuspid aortic valve from the definition of critical fetal congenital heart disease. Probabilities and costs were derived from the literature. We used individual models to evaluate different scenarios: first-trimester Hb A1c lower than 6.5%, Hb A1c 6.5–9.0%, and Hb A1c higher than 9.0%. Primary outcomes included fetal death, neonatal death, and false-positive and false-negative results. A cost-effectiveness threshold was set at $100,000 per quality-adjusted life-year. Univariable sensitivity analyses were performed to investigate the drivers of the model. RESULTS: Universal fetal echocardiogram is not cost effective except for when first-trimester Hb A1c level is higher than 9.0% (incremental cost-effectiveness ratio $638,100, $223,693, and $67,697 for Hb A1c lower than 6.5%, 6.5–9.0%, and higher than 9.0%, respectively). The models are sensitive to changes in the probability of congenital heart disease at a given Hb A1c level, as well as the cost of neonatal transfer to a higher level of care. Universal fetal echocardiogram became both cost saving and more effective when the probability of congenital heart disease reached 14.48% (15.4 times the baseline risk). In the Monte Carlo simulation, universal fetal echocardiogram is cost effective in 22.7%, 48.6%, and 62.3% of scenarios for each of the three models, respectively. CONCLUSION: For pregnant patients with first-trimester Hb A1c levels lower than 6.5%, universal fetal echocardiogram was not cost effective, whereas, for those with first-trimester Hb A1c levels higher than 9.0%, universal fetal echocardiogram was cost effective. For those with intermediate Hb A1c levels, universal fetal echocardiogram was cost effective in about 50% of cases; therefore, clinical judgment based on individual patient values, willingness to pay to detect congenital heart disease, and resource availability needs to be considered.