Prevalence of isolated systolic hypertension in the population over 55 years old. Results from a national study

INTRODUCTION Isolated systolic hypertension (ISH) is an important risk factor for cardiovascular events (myocardial infarction and stroke) and premature mortality, particularly in the elderly population. Among this population, it is an even better predictor of morbidity and mortality than diastolic blood pressure (BP). This cooperative survey was promoted by the World Hypertension League, Associação Portuguesa de Hipertensão, Instituto Nacional de Cardiologia Preventiva, Sociedade Portuguesa de Cardiologia, Sociedade Portuguesa de Geriatria, Sociedade Portuguesa de Medicina Intema, and Direcção Geral de Saúde, with the collaboration of Servier Portugal. OBJECTIVES The aim of this survey was to evaluate the prevalence of ISH within the Portuguese elderly population (aged 55+) during the year 2000, compared and together with other countries, in order to estimate its worldwide prevalence. Secondary objectives were to investigate demographic factors related to ISH (age, gender and other cardiovascular risk factors) and to analyze the effects of repeated blood pressure measurements on prevalence and on postural variations in blood pressure. METHODS We performed a survey including 108 primary care centers. General practitioners were invited to include the first consecutive 15 patients aged over 55 years. Subjects were be selected over a period of one week and had to agree to attend three visits. All blood pressure measurements were to be performed in accordance with the standards of the 7th Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). 1031 subjects were included in this survey. CONCLUSIONS We concluded that ISH prevalence ranges between 20.3% in primary" care patients and 35% in the community, using mean values of both systolic and diastolic BP. ISH prevalence is higher among women; it increases with age, decreasing slightly after the age of 70. Risk factors include gender, age and family history of hypertension. The predictive value for ISH diagnosis is 100% and 65% with methods ISH-1 and ISH-2 respectively, with positive predictive value of 51.05% and 63% for ISH-1 and ISH-2 respectively. Orthostatic hypotension prevalence is higher at 5 minutes than at 2 minutes and is higher among elderly subjects. The prevalence of untreated hypertension in the Portuguese population aged over 55 years, according to the WHO/ISH criteria, was 44.92%.