Cost Comparison of Repeat Placental Growth Factor-Based Testing in Women with Suspected Preterm Pre-eclampsia, Compared to Usual Care: The PARROT-2 Trial

OBJECTIVES: The aim was to evaluate health resource use and cost, and conduct a cost comparison of repeat placental growth factor (PlGF)-based testing for suspected pre-eclampsia, compared with usual care. METHODS: This was a health economic evaluation in women participating in the PARROT-2 trial of repeat revealed PlGF-based testing, compared to usual care, for suspected preterm pre-eclampsia in 22 maternity units in England, Scotland, and Wales, (ISRCTN85912420, 25/11/2019). We conducted a cost comparison analysis, describing health resource use and associated cost per woman, infant, and mother-infant dyad according to randomised allocation to repeat revealed PlGF-based testing or usual care with repeat concealed testing. Additional analysis was stratified according to the initial PlGF-based test result (normal, abnormal, or very abnormal). A post-hoc, within-trial cost-effectiveness analysis was also conducted. RESULTS: Between December 17, 2019, and September 30, 2022, 1253 participants were randomised. Costs per woman, infant, or mother-infant dyad were similar between the repeat revealed testing group and the group receiving usual care with repeat concealed testing. In the revealed group compared to the usual care group, there were significantly greater costs associated with neonatal admissions for special care (mean difference £1169 95% confidence interval 398-1939), but not neonatal intensive care or high-dependency care. Costs correlated with the initial PlGF-based test result, with the highest costs per mother-infant dyad in the group with a very abnormal initial test result (£38,284 [standard deviation {SD} 35,997]) and lowest costs in the group with a normal initial test result (£13,156 [SD 9568]). Repeat testing was unlikely to be cost-effective, and the cost-effectiveness acceptability curve demonstrated low probability for a range of decision thresholds. CONCLUSION: There is no evidence of an overall significant difference in cost associated with a policy of universal, routine repeat testing, compared to usual care, in women receiving an initial PlGF-based test for suspected pre-eclampsia.