Safety, clinical effectiveness, predictive accuracy and cost effectiveness of blood based tests for women with suspected preeclampsia: a health technology assessement

Two to eight percent of pregnant women are diagnosed with preeclampsia worldwide. Preeclampsia is a potentially life-threatening condition requiring hospital admission and close maternal and fetal monitoring in the second half of pregnancy. Tests based on biomarkers like placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) may predict preeclampsia and lead to better pregnancy outcomes. Such tests are also proposed as a means of identifying women at low risk so that a) unnecessary admissions can be avoided, and b) they can return home reassured. In this health technology assessment, we address safety, effectiveness, predictive accuracy, and cost-effectiveness of these tests among pregnant women with suspected preeclampsia from gestational week 20. Clinical effectiveness (three included studies): • PlGF tests may reduce the time to a preeclampsia diagnosis and may reduce the risk of severe maternal adverse outcomes e.g. cerebral haemorrhage. • We are unable to conclude whether sFlt-1/PlGF or PlGF testing improve neonatal outcomes or not. Health services utilisation (two included studies). • sFlt-1/PlGF ratio tests may increase admission rates the first 24 hours after the test, but this result is uncertain. • sFlt-1/PlGF ratio tests were associated with little or no differences in hospital admissions within the first week after the test, and for the remainder of the pregnancy. Predictive accuracy (four included systematic reviews). • the predictive accuracy of sFlt-1/PlGF ratio tests is fairly good, and may be useful to “rule out” suspected preeclampsia. Budget impact of adding blood-based test to clinical practice. • We estimate that introducing sFlt-1/PlGF ratio or PlGF test for women with suspected preeclampsia will lead to a direct budget impact of approximately 12.4 million Norwegian kroner annually. Potential health care savings due to earlier diagnosis and reduction in maternal adverse outcomes remain to be explored. Therefore, the current evidence is insufficient to conclude about the comprehensive economic impact of introducing sFlt-1/PlGF or PlGF testing. Benefit-, resource- and the severity criteria: The tests evaluated may aid to predict the risk of developing preeclampsia. We are, however, not sure how useful the tests are in clinical practice, and there are some serious limitations in the included studies. Using the tests might, or might not, reduce the use of health care resources. Preeclampsia is a very serious condition and early detection might prevent serious outcomes