Association of statin prescription with small abdominal aortic aneurysm progression

Abstract

Background: Statins have been suggested to reduce expansion of abdominal aortic aneurysms (AAAs) independent of lipid-lowering effects.

Methods: We assessed the association of statin treatment and serum low-density lipoprotein (LDL) concentrations with small AAA expansion. Six hundred fifty-two patients undergoing surveillance of small AAAs were entered into the study from 5 vascular centers. In a subset, fasting lipids (n = 451) and other biomarkers (n = 216) were measured. The AAA diameter was followed by ultrasound surveillance for a median of 5 years.

Results: Three hundred forty-nine (54%) of the patients were prescribed statins. Adjusting for other risk factors, statin prescription was not associated with AAA growth (odds ratio [OR] 1.23, 95% CI 0.86-1.76). Above-median AAA growth was positively associated with initial diameter (OR 1.78 per 4.35-mm-larger initial aortic diameter, 95% CI 1.49-2.14) and negatively associated with diabetes (OR 0.37, 95% CI 0.22-0.62). Above-median serum LDL concentration was not associated with AAA growth. Patients receiving statins had lower serum C-reactive protein concentrations but similar matrix metalloproteinase-9 and interleukin-6 concentrations to those not prescribed these medications.

Conclusions: We found no association between statin prescription or LDL concentration with AAA expansion. The results do not support the findings of smaller studies and suggest that statins may have no benefit in reducing AAA progression.

Figure 1

Median maximum infrarenal abdominal aortic diameter (mm) of patients treated with and without statins during six years of ultrasound surveillance. Vertical error bars represent interquartile range.

Figure 2

Association of statin prescription and AAA growth. Shown are adjusted odds ratios and 95% confidence intervals (CI) for different centers. AAA growth was defined as < or >= median. The New South Wales (NSW, n=30), Victoria (VIC, n=21) and New Zealand (NZ, n=34) cohorts were grouped since the cohorts were small. Western Australia (WA, n=458) and Queensland (QLD, n=109) cohorts were larger.