INTRODUCTION: Abdominal Aortic Aneurysm (AAA) is a common progressive disease and a significant cause of morbidity and mortality. Prior investigations have shown that diabetes mellitus (DM) may be relatively protective of AAA incidence and growth. The Non-invasive Treatment of Aortic Aneurysm Clinical Trial (N-TA3CT) is a contemporary study of small AAA growth which provides a unique opportunity to validate and explore the effect of DM on AAA. Confirming the effect of DM on AAA growth in this study may present opportunities to explore for clues to potential biologic mechanisms as well as inform current patient management.METHODS: This is a secondary analysis examining the association of diabetes and aneurysm growth within N-TA3CT: a placebo-controlled multicenter trial of doxycycline in 261 patients with AAA maximum transverse diameters (MTD) between 3.5cm and 5cm. The primary outcome is the change in the MTD from baseline as determined by CT scans obtained during the trial. Secondary outcome is the growth pattern of the AAA. Baseline characteristics and growth patterns were assessed with t-tests (continuous) or chi-square tests (categorical). Unadjusted and adjusted longitudinal analyses were performed with a repeated measures linear mixed model to compare AAA growth rates between diabetic patients and non-diabetic patients.RESULTS: Of 261 patients, 250 subjects had sufficient imaging and were included in this study. There were 56 (22.4%) with diabetes and 194 (77.6%) without. Diabetes was associated with higher BMI and increased rates of hypercholesterolemia and coronary artery disease (p< 0.05). Diabetes was also associated with increased frequency of treatment for atherosclerosis and hypertension including treatment with statin, angiotensin-converting enzyme inhibitor, ARB, anti-platelet, and diuretic therapy (p< 0.05). Baseline MTD was not significantly different between those with (4.32 cm) and without diabetes (4.30 cm). Median growth rate for diabetic patients was 0.12 cm/year (IQR 0.07-0.22) and 0.19 cm/year (IQR 0.12-0.27) in patients without diabetes, which was significantly different on unadjusted analysis (p<0.0001). Diabetes remained significantly associated with AAA growth after adjustment for other relevant clinical factors (coef -0.057; p<0.0001).CONCLUSIONS: Patients with diabetes have more than a 35% reduction in the median growth rates of AAA despite more severe concomitant vascular co-morbidities and similar initial sizes of aneurysms. This effect persists and remains robust after adjusted analysis; and slower growth rates may delay the time to reach repair threshold. Rapid growth (>0.5 cm/year) is infrequent in diabetic patients.
View details for DOI 10.1016/j.jvs.2021.10.019
View details for PubMedID 34695550