Abstract
INTRODUCTION: Diabetes mellitus (DM) is an important health issue that affects the ageing population. China has the largest geriatric population and the largest number of diabetes cases in the world. This poses a significant challenge for healthcare providers and policymakers. Haemoglobin A1C (HbA1c), which is one of the diagnostic criteria for diabetes, is affected by many factors such as pregnancy, age, race and anaemia. Glycated albumin (GA) is not influenced by factors that affect HbA1c concentrations, although it has been used in the diagnosis of diabetes in a few people. The aim of this study protocol is to determine reference intervals (RIs) of HbA1c and GA for the diagnosis of older adults with diabetes in China and to assess the optimal cut-off values for these parameters from a health economic perspective. METHODS AND ANALYSIS: This cross-sectional survey study will recruit 1278 community-dwelling older adults aged 60-89 in Chengdu City. The data collection process will involve a questionnaire survey, a comprehensive physical examination and the collection of blood samples for laboratory testing. Data analyses will be conducted on the pooled sample and stratified by gender, age or other demographic features if necessary. Rates will be compared using the χ2 test or Fisher test and receiver operating characteristic (ROC) curves will be used to identify the most effective threshold values for HbA1c and GA for diagnosing diabetes among older adults in China. ETHICS AND DISSEMINATION: The study protocol was approved by the ethics review board of the Bioethics Subcommittee of West China Hospital, Sichuan University (Approval No. 1705 in 2022). The study's results will be disseminated through peer-reviewed journals and scientific conferences. TRIAL REGISTRATION NUMBER: ChiCTR2300070831.