Blood pressure and cardiovascular morbidity and mortality rates in the elderly.

The influence of blood pressure on the development of cardiovascular disease and mortality rate beyond 75 years of age has been uncertain. A reported inverse relation to mortality rate noted in the very old could reflect poor cardiovascular health. This report examines the impact of blood pressure on cardiovascular morbidity and mortality rates and all-cause mortality rate in those aged 75 to 94 years. For this analysis the data were the Framingham study subjects found free of cardiovascular disease and a second sample of those with cardiovascular disease present on the biennial examinations. Investigation of the relation of systolic and diastolic blood pressures to all causes and cardiovascular morbidity and mortality rates within each 2-year interval for those aged 75 to 94 years was carried out. Over the period of 38 years of follow-up there were increasing cardiovascular morbidity and mortality rates with increasing blood pressure levels for both men and women in the sample free of cardiovascular disease. In those with cardiovascular disease at the biennial examination there was a distinct U-shaped curve of cardiovascular mortality rate in relation to systolic blood pressure in men with a substantial increase in mortality rate below systolic pressures of 120 mm Hg for both men and women. Excess mortality rate reported in elderly persons with low blood pressure appears to be a result of poor cardiovascular health and not from the low pressure itself. The excess mortality rate reported for low blood pressure levels in persons older than 75 years derives from the inclusion of the substantial proportion of this age group who have cardiovascular disease.