Prevalence and correlates of anaemia in essential hypertension.

1. Anaemia is an independent predictor of mortality in pro-atherosclerotic conditions with impaired endothelial function, such as diabetes and chronic kidney disease. However, the prevalence of anaemia in hypertension, a condition characterized by endothelial dysfunction, is unclear. 2. Haemoglobin concentration, renal function and echocardiographic parameters of 187 consecutive patients (M : F 83 : 104; mean (+/-SD) age 58 +/- 15 years) who underwent ambulatory blood pressure monitoring between 2005 and 2006 were assessed in a tertiary level university hospital. 3. The prevalence of normocytic anaemia in our cohort of hypertensive patients was 16% and was higher in patients with uncontrolled hypertension (20%) than among those with well-controlled hypertension (4%; P = 0.03). Red cell indices (mean corpuscular volume, mean cell haemoglobin and mean cell haemoglobin concentration) did not differ between the groups. However, the haemoglobin concentration was progressively lower between patients with well-controlled hypertension and uncontrolled hypertension (P = 0.007). Haematological parameters did not correlate to echocardiographic indices of left ventricular size and function. 4. Normocytic anaemia was highly prevalent in hypertensive patients. Poor blood pressure control was associated with lower haemoglobin concentration. This may indicate a higher cardiovascular risk in uncontrolled hypertension, as in other pro-atherosclerotic conditions. Additional studies are needed to evaluate the effect of anaemia on morbidity and mortality in hypertensive patients.