Critical outcomes to be included in the Core Outcome Set for nutritional intervention studies in older adults with malnutrition or at risk of malnutrition: a modified Delphi Study

Introduction: As part of the development of an agreed minimum set of outcomes or Core Outcome Set (COS) for future nutritional intervention trials in older adults with malnutrition or at risk of malnutrition, this work reports on the Delphi surveys and final consensus. Methods: Outcomes from a scoping review were incorporated into a two-round Delphi survey. Researchers and healthcare professionals experienced in malnutrition in older adults were invited to take part in an online survey to rate 38 selected outcomes on a nine-point Likert scale ranging from 'not important' to 'critical' for their setting (community, hospital, or long-term care). Consensus for inclusion was reached when >= 75% (or >= 60% if a patient-reported outcome) of the participants scored the outcome as 'critical' and <15% as 'not important'. Resulting outcomes were voted for inclusion or exclusion in the COS in a final online consensus meeting. Results: Ninety-three and 72 participants from diverse professional backgrounds and countries participated in the 1st and 2nd Delphi round, respectively. After both rounds eleven outcomes met the inclusion criteria, largely irrespective of setting. Fifteen participants, representing academia, health care, health policy, industry, and PPI, voted in a final online consensus meeting resulting in ten outcomes: malnutrition status, dietary intake, appetite, body weight or BMI, muscle strength, muscle mass, functional performance, functional limitations, quality of life, and acceptability of the intervention. Conclusions: Ten outcomes will form the COS which is intended to be used by the scientific community in all future nutritional intervention studies for older adults with malnutrition or at risk of malnutrition. The subsequent phase will establish the appropriate methods to measure these outcomes.