Economic Evaluation Seminar - Extending RCT evidence for decision making: A case study using Network Meta-Analysis and economic modelling in venous leg ulcers

Event details

Abstract 

Randomised controlled trials (RCTs), when well designed, provide robust internal validity and remain the gold standard for assessing the relative effectiveness of interventions. However, a single RCT is rarely sufficient to inform health care decisions where multiple treatment options must be compared simultaneously. Broader decision-making requires integration of external evidence, often through network meta-analysis (NMA).

In this study, we extended the evidence base from the VenUS 6 trial - a large, pragmatic RCT comparing three high-compression systems for venous leg ulcers - by incorporating all relevant external studies and treatment comparisons. We used a multilevel NMA to combine individual participant data (IPD) from VenUS 6 and other RCTs, where available, with aggregate-level data from the broader evidence base. The resulting relative treatment effects were then translated into lifetime health and cost outcomes using a decision-analytic model, with key inputs (e.g. utilities and resource use) primarily derived from VenUS 6.

Our approach aligns with NICE methodological preferences. However, expanding the evidence base can introduce bias, particularly when small studies of lower quality “manipulate” the evidence network (i.e., two evidence loops are linked by low quality RCTs). We will describe our approach to assess and mitigate this risk. We will also present our approaches for costing complex interventions (e.g. treatment switching; upfront vs. ongoing costs), as well as our approach to estimate the health state's utility.

Finally, we will discuss how the findings were used to inform a pilot NICE late-stage assessment (in which an independent model was developed by a separate External Assessment Group). We will discuss how differences in the use and interpretation of evidence can materially influence policy recommendations.

Bio: Thai Han Phung (Han) is a Research Fellow in Economic Evaluation (TEEHTA). He joined TEEHTA in November 2021 after completing the MSc in Health Economics at the University of York (with distinction). Previously, Han had worked in the pharmaceutical industry for 7 years (in Vietnam) in management roles. His research interests encompass the economic evaluation of health and care interventions. He currently works in the NIHR Technology Assessment Reviews (TAR) programmes. 

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