SFlt-1/PlGF Testing in a Canadian Low-Resource Setting: A Prospective Study Evaluating Implementation and...

Testing for placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) is known to reduce time to diagnosis of preeclampsia and identify patients at increased risk of adverse perinatal outcomes. We implemented testing of sFlt-1/PlGF and sought to compare the time to diagnosis of preeclampsia before and after implementation, as well as selected outcomes and estimated costs.

Singleton pregnancies between 20⁰ and 34⁶ weeks gestation with suspected preeclampsia or placental dysfunction were identified by the hospital databases retrospectively from 2019 to 2021 and prospectively after implementation of sFlt-1/PlGF from 2022 to 2023. Outcomes were compared using negative binomial and Poisson regression models with entropy balancing to adjust for confounding.

Before and after the implementation of sFlt-1/PlGF testing, a total of 494 and 145 patients were identified, respectively. Among the 206 patients with confirmed preeclampsia, those identified after implementation had an earlier mean gestational age at the time of diagnosis (31.8 weeks vs. 33.1 weeks, P = 0.001). The post-implementation cohort had a higher risk of neonatal intensive care unit admission ≥24 hours (risk ratio 3.85; 95% CI 2.07-7.17). All fetal deaths (5.0%) recorded after implementation had a positive sFlt-1/PlGF result.

Among patients with suspected preeclampsia, sFlt-1/PlGF testing did not decrease the time to diagnosis of preeclampsia; it was associated with an earlier gestational age at time of diagnosis, identified patients with increased risk of neonatal intensive care unit admission and adverse fetal outcomes, and supports optimization of access to biochemical marker testing in regional centres.