Relationship between insulin resistance and end-organ damage in white coat hypertension

End-organ damage is seen in some patients suffering from white coat hypertension (WCH). It remains unclear which patients elude the risk of end-organ damage. A relationship between end-organ damage and insulin resistance was hypothesized.

This hypothesis was tested by comparing two groups of patients with WCH: those presenting with end-organ damage and those without end-organ damage. Both groups were tested for the presence of insulin resistance. The study was conducted in the outpatient clinics of the Internal and Family Medicine Departments of Cerrahpasa Medical School, Istanbul University. In this study 290 patients were screened for WCH, of which 75 were included in the study. The WCH was defined as an office blood pressure (BP) >/=140/90 mm Hg and mean daytime BP <135/85 mm Hg. The patients were divided into two groups according to the presence of end-organ damage. All patients received 24-h ambulatory BP monitoring. End-organ damage was diagnosed by revealing left ventricular hypertrophy on echocardiographic examination or retinopathy with fundoscopic examination. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance.

Among 75 patients with WCH, hypertensive retinopathy was detected in 25 patients, left ventricular hypertrophy in 15 patients, and both retinopathy and left ventricular hypertrophy simultanously in 6 patients. There were no significant differences between the groups regarding age, sex, lipid profile, and glucose levels. The HOMA-IR values in the patients with WCH and end-organ damage (4.2 +/- 1.7) were significantly higher (P < .0001) than those determined in patients with WCH but without end-organ damage (2.6 +/- 1.8). In patients with WCH with HOMA-IR values above 3 the risk of end-organ damage was found to be higher.

A possible relationship between end-organ damage and insulin resistance in patients with WCH exists.