Association between red cell distribution width and markers of inflammation and blood pressure in a tertiary care center in Chennai, India

Background: Red cell distribution width (RDW) is a recently found marker of inflammation in acute and chronic conditions such as heart attack (myocardial infarction), heart failure, angina-pectoris, peripheral vascular disease, inflammatory conditions, and metabolic disorders such as diabetes. The literature suggests that both C-reactive protein (CRP) and RDW are elevated in hypertensive patients almost simultaneously. Hypertension is a state of chronic inflammation. Several studies have shown increased levels of inflammation markers such as CRP, high-sensitive CRP (hs-CRP), Interleukin, and IL-1β in hypertension. hs-CRP was found to predict the changes in inflammation quite earlier. Aim: A few studies have been conducted on RDW in secondary hypertensives, but none in recent hypertensives or patients with hypertension for 2 years. Hence, this study aimed to explore whether cost-efficient RDW can be considered as an alternative to CRP to assess the inflammation levels in hypertensive, pre-hypertensive, and normotensive subjects. Methods: Ethical clearance was obtained from Chettinad Medical College and Research Institute, Chennai, India, and consent was obtained from both patients and controls. This is a case-control study that included 120 individuals, who were subdivided into three groups: normotensive, 40; pre-hypertensive, 40; and hypertensive, 40. Hypertensive patients were categorized into two groups based on the duration of hypertension: recently diagnosed hypertensive patients (who were diagnosed with hypertension for less than 6 months) and those on antihypertensive medication for less than or equal to 2 years. CRP, hs-CRP analysis, was performed based on the enzyme-linked immunosorbent assay principle. Results: Pearson’s χ2 test gave a p value of 0.002, suggesting a strong association between RDW and CRP. Conclusion: Further study is required to establish cost-effective parameters, such as RDW, for the early assessment of inflammatory changes in the pre-hypertensive stage and to understand the correlation between RDW and blood pressure.