Going beyond Randomised Controlled Trials to assess treatment effect heterogeneity across target populations

Date and time:  Thursday 28 November 2024, 13:00 hours

Location: LG1 Seminar Room, Big Data Institute, Old Road Campus, Headington, OX3 7LF

To Join: This is a free event, which will be taking place both in-person and online via Microsoft Teams. Register

Abstract: Methods have been developed for transporting evidence from Randomised Controlled Trials (RCTs) to target populations. However, these approaches allow only for differences in characteristics observed in the RCT and real-world data (overt heterogeneity). These approaches do not recognise heterogeneity of treatment effects (HTE) according to unmeasured characteristics (essential heterogeneity). We use a target trial design and apply a local instrumental variable (LIV) approach to electronic health records from the Clinical Practice Research Datalink, and examine both forms of heterogeneity in assessing the comparative effectiveness of two second-line treatments for type 2 diabetes mellitus. We first estimate individualised estimates of HTE across the entire target population defined by applying eligibility criteria from national guidelines (n=13,240) within an overall target trial framework. We define a subpopulation who meet a published RCT’s eligibility criteria (‘RCT-eligible’, n=6,497), and a subpopulation who do not (‘RCT-ineligible’, n=6,743). We compare average treatment effects for pre-specified subgroups within the RCT-eligible subpopulation, the RCT-ineligible subpopulation, and within the overall target population. We find differences across these subpopulations in the magnitude of subgroup-level treatment effects, but that the direction of estimated effects is stable. Our results highlight that LIV methods can provide useful evidence about treatment effect heterogeneity including for those subpopulations excluded from RCTs.

Bio: David Lugo Palacios is a health economist with expertise in policy evaluation and applied microeconometrics. He joined the London School of Hygiene & Tropical Medicine (LSHTM) as Assistant Professor in Health Economics in November 2020, where he co-leads the Policy Evaluation theme within the Global Health ECOnomics (GHECO) centre at LSHTM. He is also an Honorary Research Fellow at Imperial College London and a Visiting Senior Fellow at LSE Health. David holds a BA in Economics from the Instituto Tecnologico Autonomo de Mexico (ITAM), an MSc in Health Economics and Policy from the Barcelona School of Economics and a PhD in Health Economics from LSHTM. Prior to re-joining LSHTM, David was a Research Fellow in Health Economics at Imperial College London and a Research Associate in Health Economics at the University of Manchester. He also has professional experience in both the public and private sectors in Mexico, including at the Ministry of Finance of the Mexico City Government, the Ministry of Social Development and a consultancy firm specialising in public finance.