Interplay Between Complete Blood Count Parameters and Atherosclerosis: The Omitted Details

To the editor,

Feng et al. reported that blood cell counts and inflammatory indexes estimated by using neutrophil, lymphocyte and platelets were related to the prevalence of femoral artery plaques. ¹ The neutrophil-to-lymphocyte ratio (NLR) was associated with atherosclerosis. However, several factors can affect the NLR (e.g. inflammation and renin angiotensin system activity). ²

There are several causes of secondary thrombocytosis. Inflammation and iron deficiency anemia are the major drivers of reactive thrombocytosis. ³ Iron deficiency was recognized as the most common nutritional disorder worldwide, and its prevalence was reported as 30%. ⁴ Therefore, it would be useful to evaluate iron deficiency in the study population to avoid a confounding impact on the platelet count.

Several drugs can affect the white blood cell count. Glucocorticoids increase the number of neutrophils while decreasing lymphocyte and eosinophil counts. ⁵ SGLT2 (sodium glucose co-transporter 2) inhibitors have become a cornerstone treatment option in patients with diabetes mellitus. ⁶ A study demonstrated that dapagliflozin led to elevated neutrophil counts, whereas lymphocyte counts remained unchanged. ⁷ Thus, possible use of these medications might have affected the results of the study.

Patients with acute infection were excluded, and the definition of acute infection was a leukocyte count >14 × 10⁹/L. ¹ Viral infections might cause both leukopenia (due to suppression of the bone marrow) and lymphocytosis. ⁸ Therefore, infection exclusion only based on increased leukocyte count is arbitrary and may not represent most viral infections.

To conclude, several factors can affect blood cell counts; they should be taken into consideration while interpreting the association between blood cell count-based parameters and atherosclerosis.