PREVALENCE, PREDISPOSING FACTORS, AND PROGNOSTIC IMPORTANCE OF POSTURAL HYPOTENSION

Objectives: To determine the prevalence and predisposing factors of po stural hypotension and to evaluate the effect of postural hypotension on 10-year vascular mortality in an elderly population. Methods: A ran dom sample of 480 subjects aged 65 years or older was obtained in 1982 . The participation rate of the subjects in the study was 72%, for a t otal of 347 subjects. Orthostatic testing and continuous ambulatory el ectrocardiographic recording, as well as comprehensive clinical evalua tion, including medical history, physical examination, standard electr ocardiography, chest radiography, blood pressure measurement, routine biochemical analysis, and determination of body mass index, were perfo rmed. In 1992, the 10-year mortality of subjects and causes of death w ere recorded from the mortality statistics. Of the participants, 184 ( 53%) had died and 163 were still alive. To determine the effect of pos tural hypotension on the 10-year mortality, the subjects who were aliv e and those who had died of vascular or nonvascular causes were compar ed. All of the examinations had been completed in 156 subjects who wer e still alive, in 109 subjects who had since died of vascular causes, and in 64 subjects who had died of nonvascular causes. Results: An abn ormal postural systolic blood pressure drop (-20 mm Hg or less) after standing for 3 minutes was demonstrated in 28.0% of subjects. There we re no sex or age differences between the subjects with and without pos tural hypotension. No predisposing factors for postural hypotension ot her than elevated blood pressure were found. Chronic cardiovascular di seases, disability, body mass index, medication, and abnormal findings in ambulatory electrocardiographic monitoring were not associated wit h postural hypotension. In the univariate analysis, the extent of syst olic or mean blood pressure change predicted neither vascular nor nonv ascular death during the 10-year follow-up. On the other hand, diastol ic blood pressure drop, in particular after standing for 1 minute, was associated with increased vascular mortality (odds ratio, 2.7; 95% co nfidence interval, 1.3 to 5.6). In the multivariate analysis, however, this association disappeared. Conclusions: Postural hypotension was c ommon in an unselected elderly population. No predisposing factors for postural hypotension other than elevated blood pressure were found. T he 10-year follow-up showed that postural diastolic, but: not systolic , blood pressure drop predicted excess vascular mortality. However, th is association disappeared in the multivariate analysis, thus being re lated to background factors such as cardiovascular diseases.