An association between chronic obstructive pulmonary disease and abdominal aortic aneurysm beyond smoking: results from a case-control study

Abstract

Objectives: It is currently unclear whether the parallels between abdominal aortic aneurysms (AAAs) and chronic obstructive pulmonary disease (COPD) are explained by common risk factors alone, such as cigarette smoking, or by a predetermined cause. Given the persistent controversy with regard to the association between AAA and COPD, we studied this association in depth.

Methods: We conducted a case-control study comparing patients with a small AAA (maximum infrarenal diameter 35-50 mm, n = 221) with controls diagnosed with peripheral artery disease (PAD, n = 87). The controls were matched to the cases for lifetime cigarette smoking. Pulmonary function was measured by spirometry, and all subjects completed a questionnaire on medical history and smoking habits (current, former and never smokers).

Results: Aneurysm patients were similar to controls with respect to gender (p = 0.71), lifetime cigarette smoking (39 vs. 34 pack years, p = 0.23) and history of cardiovascular disease (45% vs. 55%, p = 0.12). Aneurysm patients had more airway obstruction (forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) (0.69 ± 0.12 vs. 0.78 ± 0.11, p < 0.001)), which was most pronounced in never smokers (0.73 ± 0.07 vs. 0.86 ± 0.07, p < 0.001). COPD was more prevalent in aneurysm patients (44%; 98/221) than in controls (20%; 17/87) (adjusted odds ratio (OR) 3.0; 95% confidence interval (95%CI) 1.6-5.5, p < 0.001). In particular, a major proportion of AAA patients was newly diagnosed with COPD; only 40 of 98 patients (41%) with COPD (mild, moderate or severe/very severe) were known before with obstructive pulmonary defects and received treatment.

Conclusions: This study confirms an association between AAA and COPD and shows that this association is independent from smoking. Findings also demonstrate that COPD is under-diagnosed in AAA patients.