Comments on: Two-year clinical outcomes following lower limb endovascular revascularisation for chronic limb-threatening ischaemia at a tertiary Asian vascular centre in Singapore

Dear Sir, We read the article ‘Two-year clinical outcomes following lower limb endovascular revascularisation for chronic limb-threatening ischaemia at a tertiary Asian vascular centre in Singapore’ by Tay et al.[1] with great interest. The study assessed mortality and functional outcomes following lower limb endovascular revascularisation in patients with chronic limb-threatening ischaemia who predominantly had diabetes mellitus.[1] The main limitation identified was the lack of consideration for pulmonary function in measuring patient mortality post-operatively. Therefore, we would like to provide our perspective on this potential confounding variable. The study accounted for body mass index (BMI), ethnicity, employment, mobility, smoking and pre-operative functional status. Comorbidities accounted for included hypertension, type 2 diabetes mellitus, hyperlipidaemia, cardiac conditions and kidney disease. While these are undoubtedly important factors, we believe that pulmonary function and, therefore, conditions such as chronic obstructive pulmonary disease (COPD) should be further investigated. Individuals with COPD are at an increased risk of developing peripheral arterial disease (PAD).[2] Furthermore, patients with COPD are more likely to experience increased morbidity and mortality post-operatively.[3] This is supported by a study which demonstrated that mortality rates per 100,000 person-years were 30.1 in individuals with both COPD and PAD, but only 16.1 in patients with PAD only.[2] Although the study accounted for certain comorbidities associated with PAD, it did not account for respiratory conditions such as COPD. We, therefore, propose that given the increased risk of mortality in COPD, respiratory diseases should be included in patient demographics for further research. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.