Prevalence, characterisation, and clinical impact of anaemia in patients with intermittent claudication: a retrospective analysis

Introduction: Anaemia prevalence and clinical significance in intermittent claudication patients remain poorly characterised, limiting evidence-based treatment strategies. This study investigated anaemia characteristics and clinical outcomes in patients with intermittent claudication. Methods: A retrospective analysis of 403 consecutive patients with intermittent claudication attending a tertiary vascular clinic over three months in 2023 was conducted. Primary outcomes included anaemia prevalence, characterisation, treatment patterns, and 24-month clinical outcomes: chronic limb-threatening ischaemia (CLTI) progression, major amputation, mortality, and symptom improvement following anaemia treatment. Results: Among 403 patients, 307 (76.2%) underwent anaemia investigation, revealing anaemia in 54 patients (17.6% of investigated; 13.4% of total cohort). Male predominance was evident (77.8% vs 68.4% in non-anaemic, p=0.187), with peak prevalence in males aged 70-79 years (32.3% vs 12.5% in <50 years, p<0.001). Normocytic normochromic anaemia predominated (79.6%), while iron deficiency was identified in only 11.1%, though limited iron studies (33.3% of anaemic patients tested). Treatment gaps were substantial: 77.8% received no anaemia treatment despite potential benefits. Oral iron therapy demonstrated trends towards symptom improvement (70.0% vs 37.9% in untreated, OR=3.82, 95% CI: 0.65-22.4, p=0.141; NNT=3.1). Anaemia correlated weakly by significantly with bilateral claudication (66.7% vs 52.2%, p=0.003). Survival analysis revealed significant composite endpoint differences (log-rank p=0.045), with trends toward increased amputation risk (5.6% vs 2.4%, RR=2.33, 95% CI: 0.52-10.4) and mortality (11.1% vs 6.3%, RR=1.79, 95% CI: 0.68-4.71) in anaemic patients. Conclusion: Anaemia affects one in five intermittent claudication patients and represents a significant treatment gap with 77.8% receiving no therapy. Iron therapy shows promise for symptom improvement (NNT=3.1), while anaemia associates with worse clinical outcomes. Systematic screening and treatment protocols warrant implementation in vascular practice.