Orthostatic hypotension and subjective symptomatic orthostasis in Parkinson's disease: Associations and correlations

Both measured orthostatic hypotension and symptomatic orthostasis are common in PD but their relationship is unclear.

We aim to determine clinical predictors of both measured orthostatic hypotension and reported symptomatic orthostasis in PD, including the impact of "on"/"off" status and seasons, and to determine the correlation between measured OH and subjective orthostasis.

We analyzed BP readings, demographic and disease state predictors for both 1. Measured blood pressure OH criteria and 2. The subjective report of orthostatic symptoms, using logistic regression analyses from an initial "on" motor state clinical visit in all PD patient visits. We then correlated subjective orthostasis symptoms with BP measurements. We also compared intra-subject BP measures in PD patients seen in both "on" and "off" states, and when seen "on" in both summer and winter.

723 consecutive visits over 2 years identified 250 unique PD individuals. Subjective orthostasis was reported by 44 % and "on" measured OH (>20 drop in SBP or 10 DBP upon standing) was seen in 30 %. Measured OH did not significantly correlate with any assessed clinical feature or specific medicine. Subjective orthostasis correlated most with older age, dementia, and L-dopa use. Subjective orthostasis correlated equally with absolute lower measured standing SBP and the drop in SBP from sitting to standing. Compared to the "off" state, "on" state showed lower sitting and standing SBP, more than DBP, but no significant change in BP drop upon standing. Seasons did not impact measured BP.

Both OH and symptomatic orthostasis are common. Dopaminergic medications did not cause traditionally defined OH but lowered all SBP (sitting and standing) and thus reduced pulse pressure, possibly by increasing arteriole compliance simply by reducing motor tone, as this BP-lowering effect may be specific to Parkinsonism.