ARE INSULIN METABOLISM AND NIGHTTIME BLOOD-PRESSURE RELATED TO LEFT-VENTRICULAR HYPERTROPHY

Essential hypertensives in whom blood pressure does not fall during sl eep (non-dippers) are thought to be at greater risk of cardiovascular morbidity. Insulin resistance is also suggested to be a risk factor fo r cardiovascular morbidity. The purpose of the present study was to ev aluate the relationship of insulin metabolism to left ventricular hype rtrophy in dippers and non-dippers. Thirty male, non-diabetic out-pati ents with newly diagnosed arterial hypertension were included in the s tudy: 21 dippers (mean age 45 +/- 13 years; body mass index 28.2+/-4.0 kg/m(2)) and nine non-dippers (mean age 48+/-10 years, body mass inde x 28.6+/-3.9 kg/m(2)). Patients were subdivided into dippers and non-d ippers on the basis of 24-h ambulatory blood pressure monitoring. Insu lin and glucose responses to an oral glucose load have been evaluated. C-peptide levels were determined. Left ventricular mass was assessed by echocardiography. Non-dippers had significantly higher mean night-t ime systolic (non-dippers: 148+/-9; dippers: 123+/-16 mmHg; P<0.001), diastolic blood pressure (non-dippers: 90+/-8; dippers: 77+/-8 mmHg; P <0.001) and non-significantly higher left ventricular mass (279+/-92 g ) and left ventricular mass index (135+/-46 g/m(2)). No significant di fference was found between C-peptide, insulin, glucose levels and incr emental areas between the two groups. Night-time blood pressure, insul in, C-peptide and glucose did not correlate with left ventricular mass in non-dippers. Dippers showed a positive correlation between fasting C-peptide and left ventricular mass (r=0.48, P=0.02) and between gluc ose and left ventricular mass (r=0.42, P=0.05). Our data indicate that night-time blood pressure and insulin are not related to left ventric ular hypertrophy in patients with essential hypertension. (C) 1998 Els evier Science Ireland Ltd.