Opposite Associations of Aortic Aneurysm With Blood Glucose and With Diabetes Mellitus
Authors: Dylan R. Morris, Paul Sherliker, Rachel Clack, David Preiss, Kin Bong Hubert Lam, Jennifer Carter, Alison Halliday, Richard Peto, Sarah Lewington, Richard Bulbulia
Journal: Circulation (2019)

◼ blood glucose ◼ diabetes mellitus ◼ prediabetic state T he prevalence of aortic aneurysm is inversely associated with the prevalence of diabetes mellitus, but the reasons for this inverse relationship remain unclear. 1 The 2 main hypotheses to explain it are the following: (1) high blood glucose, or some other aspect of diabetes mellitus, has a direct fibrotic or other effect on the aortic wall that inhibits aneurysm development (in which case prediabetes could well have a protective effect); or (2) some common diabetes treatment protects against aneurysm development. 1These hypotheses predict different relationships of prediabetes to aneurysm development, yet no large studies have assessed the associations of blood glucose with subclinical aortic aneurysm among people without diabetes mellitus.The aim of this study was to assess the associations of blood glucose with screen-detected aortic aneurysm in a large population of otherwise healthy adults without diabetes mellitus.The population comprised self-referred adults who attended commercial vascular screening clinics in the United Kingdom/United States from 2008 to 2013.They underwent ultrasound screening for aortic aneurysm, carotid stenosis, and peripheral artery disease.Diabetes mellitus was defined by previous diagnosis or antihyperglycemic treatment.Blood glucose was measured in capillary blood samples at pointof-care (Cholestech LDX) by using the oxidase/peroxidase method, 2 of which >90% were fasting samples.The LDX method has a mean bias of -0.8 mmol/L (SD 0.6) and a percentage bias of -17.6% (SD 13.4) for the measurement of blood glucose in comparison with standard methods. 2Vascular screening was conducted using dedicated vascular ultrasound instruments (GE LOGIQ e).Aortic aneurysm was defined as a maximum infrarenal aortic diameter ≥3 cm.Analyses were restricted to findings at the first screening examination, and, to minimize the influence of reverse causation, excluded participants who reported a previous diagnosis of ischemic heart disease, stroke, transient cerebral ischemia, peripheral artery disease, or aortic aneurysm.Participants were not representative of the general population, but this should not materially bias any associations between screen-detected arterial lesions and either diabetes mellitus or blood glucose.Multivariable logistic regression was used to assess the associations of blood glucose (among people without diagnosed diabetes mellitus) and of diabetes mellitus itself (in the entire population) with screen-detected vascular disease.Analyses were adjusted for age, sex, body mass index group, systolic blood pressure, smoking, and region, and for the use of aspirin, antihypertensive therapy, and low-density lipoprotein cholesterol-lowering therapy.Odds ratios in 4 categories defined by blood glucose measurements at the first screening invitation were plotted against the usual blood glucose levels in those categories (ie, the mean glucose values including the first resurvey measurement, to correct for regression dilution). 3The results are therefore referred to in terms of usual blood glucose differences, as opposed to differences in baseline blood glucose levels that may underestimate the magnitude of risk factor