Prevalence of orthostatic hypotension in Parkinson's disease

OBJECTIVES: To investigate the prevalence of orthostatic hypotension and the nature of the postural events related to a fall in blood pressure in patients with Parkinson's disease. METHODS: Blood pressure was measured first in a supine position after a rest of at least 15 minutes and every minute during 10 minutes of an active standing up procedure. Orthostatic hypotension was considered as present when a fall of at least 20 mm Hg of systolic blood pressure was recorded. Postural events which occurred during the standing test were identified from a questionnaire and self reporting. Statistical analysis was performed to determine the relation between orthostatic hypotension and disease characteristics (duration, severity) and the use of antiparkinsonian drugs. Ninety one consecutive patients with Parkinson's disease (48 women, 43 men, mean age 66 (SD 9) years) participated to the study. RESULTS: A fall of at least 20 mm Hg of systolic blood pressure was found in 58.2% of the patients. Orthostatic hypotension was asymptomatic in 38.5% and associated with postural events in 19.8% of the patients. Symptomatic (but not asymptomatic) orthostatic hypotension was related to duration and severity of the disease and with the use of higher daily levodopa and bromocriptine doses. The analysis of the relation between the postural symptoms (and the need for standing test abortion) with the fall in systolic blood pressure allowed the identification of six clinical criteria specific of orthostatic hypotension. A direct relation between the postural changes in systolic blood pressure and the number of clinical events in this clinical scale was found. CONCLUSION: The frequency of orthostatic hypotension in Parkinson's disease is high and it is possible to establish a clinical rating scale which could be used to assess the effects of drugs employed in the management of orthostatic hypotension.