[Reduction of the expansion rate of small abdominal aortic aneurysms with roxithromycin. Results from a randomized controlled trial].

Introduction: Macrolide treatment has been reported to reduce the risk of recurrent ischaemic heart disease. The influence of a macrolide on the expansion rate of small abdominal aortic aneurysms (AAA) is unknown at present. The aim of this study was to investigate the effect of roxithromycin on the expansion rate of small AAA.

Materials And Methods: A total of 92 patients with a small AAA were recruited from two populations. One population consisted of 6.339 men aged 65-73 years who were offered participation in a mass screening programme for AAA at the local hospital. From this population 66 subjects were recruited. The remaining 26 were recruited from among 49 subjects diagnosed at interval screening for an initial aortic diameter between 25 mm and 29 mm. The patients were randomized to receive either oral roxithromycin 300 mg once daily for 28 days or matching placebo, and followed for a mean of 1.5 years.

Results: During the first year the mean annual expansion rate of AAA was reduced by 44% in the macrolid group (1.56 mm/year) compared to 2.80 mm/year after placebo (p = 0.02). During the second year the difference was only 5%. Multiple linear regression analysis showed that roxithromycin treatment and initial AAA size were significantly related to AAA expansion when adjusted for smoking, diastolic blood pressure, and IgA level > or = 20. The logistic regression analysis confirmed a significant difference in expansion rates above 2 mm annually between the intervention and placebo groups, OR = 0.09 (95% CI: 0.01-0.83).

Discussion: In comparison to placebo, roxithromycin 300 mg daily for four weeks reduced the expansion rate of AAA.