Core Outcome Measurement Set for Clinical Trials in Dengue: An International Delphi Consensus Study ‘DEN-CORE’

Summary Dengue, caused by any one of four distinct virus serotypes, is the most rapidly spreading mosquito-borne viral disease worldwide. It is a primary arboviral infection with increasing global incidence, driven by climate change, urbanisation, and the expanding range of Aedes mosquito vectors. Despite growing research interest, outcome and measurement instrument heterogeneity in dengue clinical trials remains high, limiting comparability and evidence synthesis. This project aimed to develop a globally relevant Core Outcome Measurement Set (COMS) for use in dengue clinical trials through international consensus.This consensus study followed COMET and COS-STAD guidelines and was conducted in two phases. Phase I focused on developing a core outcome set (COS) through six steps: (1) a systematic literature review; (2) qualitative interviews with people with lived experience of dengue; (3) review by the management group and steering committee; (4) a two-round modified Delphi survey and structured online consensus meetings to finalise the COS for ‘hospitalised’ and ‘early’ stages of dengue. Input from critical care experts informed recommendations for the ‘ICU/HDU’ COS. Phase II involved: (5) targeted review of outcome measurement instruments; and (6) a hybrid international consensus workshop to finalise the COMS.The agreed COMS for ‘hospitalised’ dengue included seven outcomes; the ‘early’ COS includes these plus four more. For critical care trials, use of existing ICU-specific COS was recommended. Unified definitions were developed for nine clinician-reported outcomes.The DEN-CORE COMS provides a consensus-based framework for harmonising outcome selection and measurement in dengue trials, improving comparability and supporting policy and clinical decision-making.