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. 2021 Mar 22;11(3):e046021.
doi: 10.1136/bmjopen-2020-046021.

Decision Analysis in SHared decision making for Thromboprophylaxis during Pregnancy (DASH-TOP): a sequential explanatory mixed methods pilot study protocol

Brittany Humphries  1 , Montserrat León-García  2   3 , Shannon Bates  4 , Gordon Guyatt  1   4 , Mark Eckman  5 , Rohan D'Souza  6   7   8 , Nadine Shehata  9 , Susan Jack  1   10 , Pablo Alonso-Coello  11   12 , Feng Xie  13   14
Affiliations

Decision Analysis in SHared decision making for Thromboprophylaxis during Pregnancy (DASH-TOP): a sequential explanatory mixed methods pilot study protocol

Brittany Humphries et al. BMJ Open. .

Abstract

Introduction: Decision analysis is a quantitative approach to decision making that could bridge the gap between decisions based solely on evidence and the unique values and preferences of individual patients, a feature especially important when existing evidence cannot support clear recommendations and there is a close balance between harms and benefits for the treatments options under consideration. Low molecular weight heparin (LMWH) for the prevention of venous thromboembolism (VTE) during pregnancy represents one such situation. The objective of this paper is to describe the rationale and methodology of a pilot study that will explore the application of decision analysis to a shared decision-making process involving prophylactic LMWH for pregnant women or those considering pregnancy who have experienced a VTE.

Methods and analysis: We will conduct an international, mixed methods, explanatory, sequential study, including quantitative data collection and analysis followed by qualitative data collection and analysis. In step I, we will ask women who are pregnant or considering pregnancy and have experienced VTE to participate in a shared decision-making intervention for prophylactic LMWH. The intervention consists of three components: a direct choice exercise, a values elicitation exercise and a personalised decision analysis. After administration of the intervention, we will ask women to make a treatment decision and measure decisional conflict, self-efficacy and satisfaction. In step II, which follows the analysis of quantitative data, we will use the results to inform the qualitative interview. Step III will be a qualitative descriptive study that explores participants' experiences and perceptions of the intervention. In step IV, we will integrate findings from the qualitative and quantitative analyses to obtain meta-inferences.

Ethics and dissemination: Site-specific ethics boards have approved the study. All participants will provide informed consent. The research team will take an integrated approach to knowledge translation.

Keywords: haematology; health economics; maternal medicine; thromboembolism.

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Conflict of interest statement

Competing interests: ME has received grant funding from the National Institutes of Health (Eunice Kennedy Shriver National Institute of Child Health and Human Development, and National Center for Advancing Translational Sciences) and funding for investigator-initiated research from Bristol-Myers Squibb. RD has received speaking honoraria and grant funding from Ferring Inc and an early career grant from the Canadian Institutes for Health Research for projects unrelated to this study. NS has received honoraria and an educational grant from Sanofi. ML-G receives doctoral support from the Spanish Public Research Institute – Health Institute Carlos III. SB has acted as a consultant for Leo Pharma Canada (manufacturer of low molecular weight heparin) and receives unencumbered salary support through the McMaster University Eli Lilly Canada-May Cohen Chair in Women’s Health.

Figures

Figure 1
Figure 1
Study flow diagram for the DASH-TOP study. DASH-TOP, Decision Analysis in SHared decision making for Thromboprophylaxis during Pregnancy.
Figure 2
Figure 2
Screenshot of decision aid. This screenshot presents women with their estimated risk of experiencing a deep vein thrombosis (DVT). Risks are presented in both numerical and graphical format. Numerically, the risk of DVT during pregnancy is 5.5%. This means that, out of 1000 women, approximately 55 will experience a DVT if they do not take low molecular weight heparin (LMWH) and 9 will experience a DVT if they do take LMWH. Overall, 46 fewer women will experience a blood clot when taking LMWH compared with not taking LMWH. The graphic represents a room of 1000 women. The 945 figures who are coloured in grey represent those women who were not destined to experience a DVT and would take daily injections of medication for the rest of their pregnancy with no benefit. The nine black figures represent women who will take the medication regularly and still experience a DVT during pregnancy because LMWH is not 100% effective. The orange figures represent the 46 women who would have experienced a DVT in their pregnancy and will avoid the blood clot because they took LMWH. The overall certainty of the evidence informing these estimates is low due to the types of studies that were conducted and the small sample sizes.
Figure 3
Figure 3
Screenshot of visual analogue scale. This screenshot demonstrates a visual analogue scale where participants are asked to place each health state along a ‘feeling thermometer’ that represents their preference on a scale of 0 (dead) to 100 (perfect health). In this hypothetical example, pulmonary embolism, deep vein thrombosis and major bleed are rated as 20, 30 and 50 out of 100, respectively.
Figure 4
Figure 4
Screenshot of decision analysis recommendation. This screenshot shows how the personalised decision analysis results are presented to participants. In this example, the decision analytic framework calculated that the average quality-adjusted life year (QALY) expected for treatment with low molecular weight heparin (LMWH) was −1 compared with expectant management without LMWH. In this case, no LMWH would be the recommended strategy because it has the greatest expected QALYs and represents the treatment option that maximises the woman’s quality of life based on available clinical evidence and the patient’s preferences.
Figure 5
Figure 5
Categorisation matrix based on quantitative results. LMWH, low molecular weight heparin.
See this image and copyright information in PMC

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