Anaemia prevalence, characterisation, and clinical impact in intermittent claudication.

INTRODUCTION: The prevalence and clinical impact of anaemia in patients with intermittent claudication is unclear and consequently evidence-based treatment strategies are ambiguous. 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: symptom improvement following anaemia treatment, progression to chronic limb-threatening ischaemia (CLTI), major amputation, major adverse cardiovascular events (MACE), and all-cause mortality. RESULTS: Among 403 patients, 307 (76.2%) underwent anaemia investigation, which identified anaemia in 54 cases (17.6%), of whom 77.8% were male. Most patients had mild anaemia (n=48, 88.9%), with the remainder having moderate anaemia (n=6, 11.1%). Severe anaemia was not observed in this cohort. Normocytic normochromic anaemia predominated (79.6%, n=43), and 14.8% (n=8) had microcytic hypochromic anaemia (p < 0.001), while iron deficiency was identified in only 11.1%, though limited iron studies (33.3% of anaemic patients tested). Treatment gaps were substantial with 77.8% did not receive any anaemia treatment. After adjustment for interval revascularisation, anaemia treatment showed a non-significant trend toward higher claudication improvement among anaemic patients (adjusted OR 4.82, 95% CI 0.96-24.22; p=0.056). Bilateral claudication was more frequent in anaemic than non-anaemic patients (66.7% vs 52.2%, p=0.052), but this did not reach statistical significance. Adjusted Cox models showed that anaemia was associated with MACE (adjusted HR=2.96, 95% CI 1.23-7.08; p=0.015) and all-cause mortality (adjusted HR=4.59, 95% CI 1.33-15.81; p=0.016), but not limb loss related outcomes. CONCLUSION: Anaemia affects approximately one in five patients with intermittent claudication and represents a significant treatment gap, with 77.8% receiving no therapy, despite anaemia was associated with higher MACE and mortality risk. A prospective randomised controlled trial evaluating the efficacy of anaemia treatment strategies in this cohort may help to improve understanding and guide clinical management.