Title: DiPEP: Diagnosis of Pulmonary Embolism in Pregnancy
Funder: Department of Health (England)

Abstract: Design: (1) Primary research involving cases identified through the UKOSS research platform and controls identified through a prospective study of pregnant and postpartum women with suspected PE. (2) Decision-analysis modelling of effectiveness cost-effectiveness and value of information. Our reasons for not using a cohort design are outlined under other information and in the project description.Setting: Hospital emergency departments and maternity units.Strategy for reviewing literature: We will undertake systematic searches for any studies of clinical predictors or biomarkers for PE in pregnancy and key parameters in the decision-analysis model.Target population: We will (a) identify pregnant and postpartum women with diagnosed PE from all UK hospitals using the UKOSS research platform and (b) recruit pregnant and postpartum women with suspected PE from 8 hospitals over 18 months. We will exclude those who did not present with suspected PE from the former group and those unable to consent requiring resuscitation or with an existing diagnosis of PE from the latter group.Health technologies being assessed: Clinical predictors and biomarkers for PE and diagnostic strategies (including clinical prediction rules) to select pregnant or postpartum women for imaging. Measurement of costs and outcomes: The nominated clinician for UKOSS will collect data from women with diagnosed PE detailing clinical variables blood tests results diagnostic imaging treatment and adverse events. Research nurses will collect clinical data and a blood sample from women with suspected PE and review hospital records at 30 days to record the results of diagnostic imaging treatment and adverse events. A questionnaire will then be sent to record adverse events health care use and health utility. Two independent assessors blind to clinical predictors and blood results will classify participants as having PE using diagnostic imaging results and details of adverse events.Sensitivities and specificities of clinical predictors biomarkers and diagnostic strategies will be estimated using data from cases and controls respectively. Decision-analysis modelling will be used to estimate costs incurred and expected outcomes from thromboembolism bleeding and radiation exposure if a hypothetical cohort of pregnant or postpartum women were investigated for suspected PE using different strategies including no imaging selective imaging and imaging for all. Outcomes will be modelled to estimate the quality-adjusted life years (QALYs) accrued by each strategy and the incremental cost per QALY gained by each strategy compared to the next most effective alternative.Sample size: Data will be collected from 150 women with diagnosed PE and 250 women with suspected PE resulting in about 155 cases and 245 controls. This will allow estimation of sensitivity or specificity of 90% with standard errors of about 2.5% and 2.0% respectively.Project timetable:Months 1-6: Preparation ethics and R&D approval finalise data collectionMonths 7-24: Primary data collection from UKOSS cases (all UK hospitals) and women with suspected PE (8 hospitals 25 per hospital per year) development of the modelMonths 25-30: Follow-up analysis modelling and writing-upExpertise in team: The team includes international experts in obstetric medicine haematology epidemiology emergency medicine vascular radiology health economic modelling and statistics.


Research activity codes: 7.3 MANAGEMENT AND DECISION MAKING;4.2 EVALUATION OF MARKERS AND TECHNOLOGIES
Health categories: REPRODUCTIVE HEALTH AND CHILDBIRTH;CARDIOVASCULAR