Hypertension as a risk factor for cardiovascular morbidity and mortality in an elderly German population

Aim To prospectively study the relationship between blood pressure levels and subsequent cardiovascular morbidity and mortality in a population aged 65 years and older. Methods Participants of the 1992 baseline survey of the population-based Starnberg Study on Epidemiology of Parkinsonism and Hypertension in the Elderly (STEPHY, 394 men and 588 women above age 65) were followed up for 3 years. Total mortality was assessed by official death data. Cardiovascular morbidity, that is, the occurrence of non-fatal events (new cases of acute myocardial infarction, angina pectoris, stroke, and heart failure) could be assessed in 681 of the 863 survivors by a second interview and analysis of general practitioners' records. The mortality and morbidity risks were compared for hypertensives (baseline blood pressure ≥160/95mmHg or antihypertensive treatment) and non-hypertensives. Results During follow-up a total of 55 men and 64 women died resulting in a 2·7-year cumulative mortality in this population of 12%. Mortality was higher in men (14%) than in women (11%). Hypertensives had no increased risk of death compared to non-hypertensives (adjusted relative risk (RR)=0·92; 95% CI: 0·48–1·76 for men and RR=1·36; 95% CI 0·67–2·78 for women). This was confirmed in age-stratified analyses. However, among survivors hypertension was associated with a significantly higher occurrence of non-fatal cardiovascular events. After controlling for potentially confounding baseline conditions, the relative risk for any event (RR=1·44; 95% CI: 1·04–2·0) and, in particular, of acute myocardial infarction (RR=5·5; 95% CI: 1·6–18·7) was raised among hypertensives. Higher rates for angina pectoris (RR=1·4; 95% CI: 0·9–2·4) and heart failure (RR 1·7; 95% CI: 0·9–2·9) were of borderline significance. Positive risk associations were confined to the age group 65 to 75 years and not detected at higher ages. Conclusion This study demonstrates for a Central European population older than 65 years the impact of hypertension as a risk factor for cardiovascular and cerebrovascular morbidity. To address the issue that risk of death showed no significant relationship to blood pressure, a longer follow-up period might be necessary.