Red cell distribution width and inflammation in patients with non-dipper hypertension

Red cell distribution width (RDW) is independently associated with morbidity and mortality in cardiovascular diseases. RDW is elevated in hypertensive patients compared with normotensives. Based on the nocturnal course, hypertension classified as dipper and non-dipper. Non-dipper hypertension is associated with higher inflammation and worse prognosis. We aimed to investigate whether RDW and high-sensitive C-reactive protein (hsCRP) are elevated in non-dipper hypertensive patients compared with dippers. The study included total 247 essential hypertensive patients. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) was performed for each patient. Thereafter patients were divided into the two groups on the basis of the results of 24-h ABPM: 127 dipper hypertensives and 120 non-dipper hypertensives. Complete blood count and biochemistry were measured by standard methods and hsCRP was assessed by using BN2 model nephelometer. Non-dippers had significantly higher RDW levels than dippers [14.6 (13.8-17.0) vs 13.0 (12.5-13.4), p < 0.001, respectively]. After adjustment for hemoglobin, low-density lipoprotein-cholesterol, sex, age and hs-CRP, mean RDW values were for dipper and non-dippers 13.4 (12.4-13.2) and 14.5 (13.7-16.8), respectively (p < 0.001). RDW was negatively correlated with the percentage decline of systolic and diastolic BP from day to night (r = - 0.392, p < 0.001 and r = - 0.294, p < 0.001, respectively). Serum hsCRP levels were also significantly higher in the non-dippers (p < 0.001) and it was significantly positively correlated with RDW (r = 0.403, p < 0.001). In receiver-operating characteristic curve analysis, the optimal cut-off value of RDW to predict non-dipping pattern was > 13.8%, with 80% sensitivity and 75% specificity. RDW is significantly increased in patients with non-dipper hypertension compared with the dipper hypertension. Inflammatory activity was closely related to RDW in non-dipper hypertensives. RDW, as easy and quick measurable tool, can predict non-dipping pattern in essential hypertension.