Glucose intolerance: the hidden danger in hypertensives!

Both systemic hypertension and abnormalities of glucose metabolism are independent recognised risk factors for the development of cardiovascular morbidity and mortality, but their effects become additive when they coexist. Hypertension and glucose intolerance increase arterial stiffness and lead to cardiac structural and functional changes such as left ventricular hypertrophy and diastolic dysfunction of the left ventricle. Oral glucose tolerance tests have shown that 58% of patients with systemic hypertension who have no cardiac history and who are not known to have diabetes, suffer from unrecognised abnormalities of glucose metabolism i.e. either diabetes or impaired glucose tolerance. Using the fasting plasma glucose level and/or glycated haemoglobin concentration to diagnose glucose intolerance in patients with systemic hypertension is insufficient because of their low sensitivity for the diagnosis of diabetes and their inability to identify impaired glucose tolerance. It is important to recognise abnormalities of glucose metabolism early in patients with systemic hypertension in order to implement appropriate management and avoid further complications. Failure to identify glucose intolerance results in serious underestimation of the cardiovascular risk of these patients and denies patients primary preventative measures, which are based on risk assessment. All patients referred to Hypertension Clinics for the management of raised blood pressure should therefore be investigated by glucose tolerance test.