Reduction of iron stores and clinical outcomes in peripheral arterial disease: outcome comparisons in smokers and non-smokers

Abstract

A prospective randomized trial suggested that iron (ferritin) reduction improved outcomes in smokers. The present study reanalyzed the trial results in smokers compared with non-smokers. Randomization of 1262 men with peripheral arterial disease (540 smokers and 722 non-smokers) to iron reduction (phlebotomy) or control groups permitted analysis of the effects of iron reduction and smoking on primary (all-cause mortality) and secondary (death plus non-fatal myocardial infarction or stroke) endpoints. Iron reduction resulted in significant improvement in the primary (hazard ratio [HR] 0.661, 95% confidence interval [CI] 0.45, 0.97; P = 0.036) and secondary (HR 0.64, 95% CI 0.46, 0.88; P = 0.006) endpoints compared with controls in smokers but not in non-smokers. Smokers required removal of a greater volume of blood to attain targeted ferritin reduction as compared with non-smokers (P = 0.003) and also exhibited differing characteristics from non-smokers, including significantly less statin use. Phlebotomy-related outcomes favored smokers over non-smokers. Biological linkages responsible for this unique effect offer promising lines for future iron reduction studies (ClinicalTrial.Gov Identifier: NCT00032357).