Diabetes and Abdominal Aortic Aneurysms

Abstract

Epidemiologic evidence suggests that patients with diabetes may have a lower incidence of abdominal aortic aneurysm (AAA); however, the link between diabetes and AAA development and expansion is unclear. The aim of this review is to analyze updated evidence to better understand the impact of diabetes on prevalence, incidence, clinical outcome, and expansion rate of AAA. A systematic review of literature published in the last 20 years using the PubMed and Cochrane databases was undertaken. Studies reporting appropriate data were identified and a meta-analysis performed using the generic inverse variance method. Sixty-four studies were identified. Methodological quality was "fair" in 16 and "good" in 44 studies according to a formal assessment checklist (Newcastle-Ottawa). In 17 large population prevalence studies there was a significant inverse association between diabetes and AAA: pooled odds ratio (OR) 0.80; 95% confidence intervals (CI) 0.70-0.90 (p = .0009). An inverse association was also confirmed by pooled analysis of data from smaller prevalence studies on selected populations (OR 0.59; 95% CI 0.35-0.99; p = .05), while no significant results were provided by case-control studies. A significant lower pooled incidence of new AAA in diabetics was found over six prospective studies: OR 0.54; 95% CI 0.31-0.91; p = .03. Diabetic patients showed increased operative (30-day/in-hospital) mortality after AAA repair: pooled OR 1.26; 95% CI 1.10-1.44; p = .0008. The increased operative risk was more evident in studies with 30-day assessment. In the long-term, diabetics showed lower survival rates at 2-5 years, while there was general evidence of lower growth rates of small AAA in patients with diabetes compared to non-diabetics. There is currently evidence to support an inverse relationship between diabetes and AAA development and enlargement, even though fair methodological quality or unclear risk of bias in many available studies decreases the strength of the finding. At the same time, operative and long-term survival is lower in diabetic patients, suggesting increased cardiovascular burden. The higher mortality in diabetics raises the question as to whether AAA repair should be individualized in selected diabetic populations at higher AAA rupture risk.

The association between body mass index and abdominal aortic aneurysm growth: a systematic review

“…Our most recent meta-analysis [6] of 19 studies demonstrated a statistically signifi cant slower growth rate in diabetic patients than in non-diabetic patients (unadjusted standardized MD (SMD), -0.32; 95% CI, -0.40 to -0.24; P < 0.00001; adjusted SMD, -0.29; 95% CI, -0.417 to -0.18; P < 0.00001). Taken together, diabetes is independently and negatively associated with both AAA presence [3,4] and growth [5,6], which suggests that decelerated mechanisms regarding the expansion of an existing AAA may be the same as those regarding the initial formation of an AAA. Further investigations are required to elucidate why BMI is not associated with AAA growth despite its trend toward a positive association with AAA presence.…”

“…An inverse association was also confi rmed by a pooled analysis of the data from smaller prevalence studies on selected populations (OR, 0.59; 95% CI, 0.35 to 0.99; P = 0.05), while no signifi cant results were provided by case-control studies. A significantly lower pooled incidence of new AAA in diabetics was found in six prospective studies (OR, 0.54; 95% CI, 0.31 to 0.91; P = 0.03) [3]. Our more recent meta-analysis [4] of exclusive adjusted estimates from 13 studies also demonstrated that diabetes was independently and signifi cantly associated with a lower prevalence of AAA (OR, 0.59; 95% CI, 0.52 to 0.67; P < 0.00001).…”

“…In a recent meta-analysis by De Rango et al [3] of 17 large population prevalence studies, which used data adjusted for local confounders at each study level and combined the adjusted data, there was a signifi cant inverse association between diabetes and AAA (OR, 0.80; 95% CI, 0.70 to 0.90: P = 0.0009). An inverse association was also confi rmed by a pooled analysis of the data from smaller prevalence studies on selected populations (OR, 0.59; 95% CI, 0.35 to 0.99; P = 0.05), while no signifi cant results were provided by case-control studies.…”

“…Interestingly, diabetes (a major risk factor of CAD and PAD) is independently and negatively associated with AAA presence [3,4]. In a recent meta-analysis by De Rango et al [3] of 17 large population prevalence studies, which used data adjusted for local confounders at each study level and combined the adjusted data, there was a signifi cant inverse association between diabetes and AAA (OR, 0.80; 95% CI, 0.70 to 0.90: P = 0.0009).…”

“…Although abdominal aortic aneurysms (AAA) share many risk factors with occlusive vascular disease, there are some distinct features of both diseases, such as the disparate association between diabetes with atherothrombosis and AAA [1,2]. Type 2 diabetes, a state of relative insulin resistance, is negatively associated with both AAA presence [3,4] and growth [5,6]. These fi ndings suggest a protective role of obesity against AAA presence or growth [1], because one of the main mechanisms by which obesity has been implicated in vascular disease is insulin resistance [7].…”