Thromboprophylaxis during pregnancy and the puerperium: a systematic review and economic evaluation to estimate the value of future research.

Background: Pharmacological prophylaxis to prevent venous thromboembolism is currently recommended for women assessed as being at high risk of venous thromboembolism during pregnancy or in the 6 weeks after delivery (the puerperium). The decision to provide thromboprophylaxis involves weighing the benefits, harms and costs, which vary according to the individual's venous thromboembolism risk. It is unclear whether the United Kingdom's current risk stratification approach could be improved by further research. Objectives: To quantify the current decision uncertainty associated with selecting women who are pregnant or in the puerperium for thromboprophylaxis and to estimate the value of one or more potential future studies that would reduce that uncertainty, while being feasible and acceptable to patients and clinicians. Methods: A decision-analytic model was developed which was informed by a systematic review of risk assessment models to predict venous thromboembolism in women who are pregnant or in the puerperium. Expected value of perfect information analysis was used to determine which factors are associated with high decision uncertainty and should be the target of future research. To find out whether future studies would be acceptable and feasible, we held workshops with women who have experienced a blood clot or have been offered blood-thinning drugs and surveyed healthcare professionals. Expected value of sample information analysis was used to estimate the value of potential future research studies. Results: The systematic review included 17 studies, comprising 19 unique externally validated risk assessment models and 1 internally validated model. Estimates of sensitivity and specificity were highly variable ranging from 0% to 100% and 5% to 100%, respectively. Most studies had unclear or high risk of bias and applicability concerns. The decision analysis found that there is substantial decision uncertainty regarding the use of risk assessment models to select high-risk women for antepartum prophylaxis and obese postpartum women for postpartum prophylaxis. The main source of decision uncertainty was uncertainty around the effectiveness of thromboprophylaxis for preventing venous thromboembolism in women who are pregnant or in the puerperium. We found that a randomised controlled trial of thromboprophylaxis in obese postpartum women is likely to have substantial value and is more likely to be acceptable and feasible than a trial recruiting women who have had a previous venous thromboembolism. In unselected postpartum women and women following caesarean section, the poor performance of risk assessment models meant that offering prophylaxis based on these models had less favourable cost effectiveness with lower decision uncertainty. Limitations: The performance of the risk assessment model for obese postpartum women has not been externally validated. Conclusions: Future research should focus on estimating the efficacy of pharmacological thromboprophylaxis in pregnancy and the puerperium, and clinical trials would be more acceptable in women who have not had a previous venous thromboembolism. Study registration: This study is registered as PROSPERO CRD42020221094. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR131021) and is published in full in Health Technology Assessment; Vol. 28, No. 9. See the NIHR Funding and Awards website for further award information.

Women who are pregnant or who have given birth in the previous 6 weeks are at increased risk of developing blood clots that can cause serious illness or death. Small doses of blood thinners given by injection are safe in pregnancy and can reduce the risk of blood clots, but they can slightly increase the risk of bleeding. Healthcare professionals use risk assessment tools to decide if a woman is at high risk of blood clots and should be offered blood thinners. We wanted to find out what research would be useful to help them make better decisions. We reviewed previous research to establish which risk assessment tools are best at predicting who will have a blood clot. We then created a mathematical model to predict what would happen when using different risk assessment tools to decide who should be offered blood thinners, both during pregnancy and after giving birth. We found that there was a lot of uncertainty about which women should be offered blood thinners. This was mainly because there have only been a few small studies comparing blood thinners to no treatment in pregnant women or women who have recently given birth. We estimated the value of future studies comparing blood thinners to no treatment, in groups of women with different risk factors, by predicting what information we would gain and how this would be used to improve decisions about using blood thinners. To find out whether these studies would be acceptable and feasible, we held workshops with women who have experienced a blood clot or have been offered blood thinners and surveyed healthcare professionals. We found that a study in obese women who have recently given birth would have substantial value and may be more acceptable than a study in pregnant women with a previous blood clot.

Risk assessment models for venous thromboembolism in pregnancy and in the puerperium: a systematic review.

OBJECTIVES: To assess the comparative accuracy of risk assessment models (RAMs) to identify women during pregnancy and the early postnatal period who are at increased risk of venous thromboembolism (VTE). DESIGN: Systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. DATA SOURCES: MEDLINE, Embase, Cochrane Library and two research registers were searched until February 2021. ELIGIBILITY CRITERIA: All validation studies that examined the accuracy of a multivariable RAM (or scoring system) for predicting the risk of developing VTE in women who are pregnant or in the puerperium (within 6 weeks post-delivery). DATA EXTRACTION AND SYNTHESIS: Two authors independently selected and extracted data. Risk of bias was appraised using PROBAST (Prediction model Risk Of Bias ASsessment Tool). Data were synthesised without meta-analysis. RESULTS: Seventeen studies, comprising 19 externally validated RAMs and 1 internally validated model, met the inclusion criteria. The most widely evaluated RAMs were the Royal College of Obstetricians and Gynaecologists guidelines (six studies), American College of Obstetricians and Gynecologists guidelines (two studies), Swedish Society of Obstetrics and Gynecology guidelines (two studies) and the Lyon score (two studies). In general, estimates of sensitivity and specificity were highly variable with sensitivity estimates ranging from 0% to 100% for RAMs that were applied to antepartum women to predict antepartum or postpartum VTE and 0% to 100% for RAMs applied postpartum to predict postpartum VTE. Specificity estimates were similarly diverse ranging from 28% to 98% and 5% to 100%, respectively. CONCLUSIONS: Available data suggest that external validation studies have weak designs and limited generalisability, so estimates of prognostic accuracy are very uncertain. PROSPERO REGISTRATION NUMBER: CRD42020221094.

The relationship between chronic kidney disease-associated pruritus and health-related quality of life: a systematic review.

BACKGROUND: Chronic kidney disease-associated pruritus (CKD-aP) is a common and burdensome condition for end-stage kidney disease (ESKD) patients, especially those receiving haemodialysis. High-quality evidence of the relationship between CKD-aP and health-related quality of life (HRQoL) can therefore inform clinicians and policymakers about treatment choice and reimbursement decisions. METHODS: A systematic literature review and narrative synthesis stratified by study design and HRQoL instrument was conducted to evaluate in adult ESKD patients receiving in-centre haemodialysis the relationship between CKD-aP and HRQoL assessed using multi dimensional generic or condition-specific preference- or non-preference-based measures. MEDLINE, Embase, Web of Science, BIOSIS Citation Index, Cochrane Library and PsycINFO from inception to March 2020 were searched, with two reviewers extracting data independently. RESULTS: Searches identified 2684 unique records, of which 20 papers relating to 18 unique studies [5 randomised controlled trials (RCTs) and 13 observational studies] were included. HRQoL was assessed using four generic and eight disease-specific measures. The impact of CKD-aP was assessed by comparison of means, linear regression and correlation. Observational studies employing comprehensively adjusted multivariable linear regression largely found associations between CKD-aP severities and HRQoL. Analyses suggest this relationship is partially mediated by the sleep disturbance caused by CKD-aP. RCTs showing improvements in CKD-aP severity were associated with clinically meaningful improvements in HRQoL. Compared with generic measures, disease-specific HRQoL instruments reported greater changes with reduced CKD-aP. Heterogeneity in study design and reporting precluded meta-analysis. CONCLUSIONS: CKD-aP severity was found to be associated with a worsening of HRQoL in the majority of observational and RCT studies. Parallel improvements in CKD-aP and HRQoL with interventions may support their use (PROSPERO registration 175035).

A systematic review to identify anxiety measures for use in populations undergoing abdominal aortic aneurysm screening.

OBJECTIVE: To identify the most appropriate patient reported outcome measure (PROM) to quantify anxiety of participants in the United Kingdom (UK) National Abdominal Aortic Aneurysm Screening Programme (NAAASP). METHODS: Comprehensive electronic searches were undertaken to identify studies reporting development or validation of PROMs used in the measurement of anxiety in screened populations. Study selection, data extraction and analysis were conducted independently by two reviewers; the "COnsensus-based Standards for the selection of health Measurement INstruments" (COSMIN) classification of measurement properties was used in the evaluation of included PROMs enabling a recommendation to be made for the most appropriate PROM for use in the NAAASP. RESULTS: The systematic review identified three PROMS that met the specified quality criteria and of these the Psychological Consequences of Screening questionnaire (PCQ) was judged to be the most appropriate PROM for use in populations undergoing screening for abdominal aortic aneurysm (AAA). Though the PCQ was developed for use in breast screening the individual items are appropriate to a population undergoing screening for AAA with minimal modification. DISCUSSION: The review was undertaken as part of a wider research initiative aiming to introduce routine measurement of anxiety alongside the UK NAAASP. A significant number of individuals participating in this screening programme will have an AAA that will never progress to a stage where it will directly cause ill health or require treatment. For these individuals the knowledge that they have an AAA could create anxiety that has a significant impact on quality of life, there is a potential for this to outweigh the benefits of screening and surveillance. CONCLUSION: In the absence of a PROM with proven validity and reliability in populations undergoing AAA screening the PCQ is a pragmatic choice as a measure of anxiety in this population and appropriate for the purposes of the NAAASP.