The first prospective registry-based cohort study focused on type 2 diabetes mellitus patients from high-altitude regions: The HLA-DR study protocol

Abstract

Abstract Background: Diabetes is the leading cause of disease burden in many countries, owing to its microvascular and macrovascular complications. Tibetans who have lived on Qinghai-Tibet Plateau for thousands of years have genetically adapted to their hypoxic high-altitude environment through positive natural selection for a hyporesponsive hypoxia-inducible factor (HIF) pathway. Highlanders have lower prevalence of type 2 diabetes mellitus (T2DM). However, whether high altitude affects diabetic complications is unclear. The Highlander diabetes registry study (HLA-DR) will investigate whether high altitude and the unique positive selection for the HIF pathway among Tibetans influence diabetes-related complications in patients with T2DM. Methods: The HLA-DR is a longitudinal, hospital-based cohort study. A total of 3,840 patients (including indigenous Tibetans and Han Chinese) will be enrolled and followed up over 5 years, to assess diabetes-related vascular complications. Baseline medical data, laboratory test results, imageological examination, and blood samples will be collected. The primary endpoints of HLA-DR will be major adverse cardiovascular events, defined as a composite of nonfatal myocardial infarction, nonfatal stroke, and death from cardiovascular causes, and a composite of microvascular complications. Patients will be followed up every 3 months by telephone and at the hospital every 1–2 years. Discussion: This study will fill an important gap in our understanding of the contribution of long-term high-altitude exposure to diabetes and its complications and will promote the optimization of medical care and disease management in residents of higher altitudes. Trial Registration: Clinicaltrials.gov: ChiCTR2000040956