White coat hypertension - 10 years follow-up

This PhD dissertation is based on research performed at the Department of Internal Medicine, Storstrommens Sygehus Naestved, in 1999-2003. The aim of this study was to evaluate the cardiovascular risk of white coat hypertension (WCH). White coat hypertension is defined by a permanently elevated BP when measured in the doctor's office (OBP), whereas average daytime BP is normal. The study is designed as a 10-year follow-up of 420 patients with newly diagnosed mild to moderate hypertension consecutively referred by their general practitioner and 146 normal controls randomly selected from the national registry. At baseline OBP and ambulatory blood pressure (ABP) was measured. With a cut-off for daytime ABP <135/90 mmHg, 76 (19%) of the hypertensives were WCH and 344 were established hypertensives (EH). At follow-up all hospital records and general practitioner files were collected concerning identification of the predefined cardiovascular endpoints. The 500 individuals still alive were invited for the 10-year follow-up examination, 412 of these accepted to participate giving a follow-up rate of 82,4%. The examination included OBP, ABP monitoring, analysis of lipids, fasting blood glucose, s-uric acid, fibrinogen and c-reactive protein and questionnaires regarding cardiovascular risk profile, health related quality of life (SF-36) and psychological profile (SCL-92). It was found that: – WCH is a cardiovascular risk factor. Cardiovascular morbidity and mortality in the WCH group was significantly higher than in the normal controls (NT) and not dissimilar from the group of treated established hypertensives. – An unfavourable metabolic risk profile was found in the WCH group regarding high trigycerides, VLDL and s-uric acid as compared to the NT group. Furthermore, the EH group had a significantly higher fasting blood glucose and tendency toward a higher fibrinogen and c-reactive protein compared to the NT group. – WCH is a prehypertensive state since 43 (70,5%) of 61 in the WCH group developed established hypertension during followup compared to 31 (43,1%) of 72 in the NT group. – In the group of EH treated and checked by their general practitioner only 28,2% had a daytime ABP <135/90 mmHg 10 years after the diagnosis of hypertension was made. – The WCH patients do not differ in health-related quality of life and psychological profile compared to the NT group whereas the EH patients as measured by two different psychometric questionnaires had significantly less psychological well-being and more psychological symptoms than the WCH group and the NT group.