Objective: Delayed orthostatic hypotension (dOH) is defined by a sustained blood pressure (BP) fall ≥20/10 mmHg occurring beyond 3 minutes in the upright position, whose clinical relevance is yet undetermined. We investigated frequency, associated features and treatment strategies of dOH in Parkinson's Disease (PD) and ageing individuals with history of syncope or orthostatic intolerance.

Methods: We retrospectively studied 213 individuals with PD and 213 age-matched individuals without parkinsonism referred for tilt-table testing to the Innsbruck and Florence Dysautonomia centres. In both cohorts, we reviewed the medical records of the 6 months before testing for history of syncope and falls, and of the 6 months afterwards for the recommended dOH treatment and clinical outcome.

Results: dOH was twice as frequent in PD than in ageing individuals [18% versus 9%; OR = 2.9 (95 CI.: 1.3-6.5), P = .007]. Upon prolonged head-up tilt, PD individuals showed a more severe systolic BP fall (P < .001). PD individuals with history of syncope also exhibited a sustained systolic BP fall from the 3rd minute of head-up tilt onward compared to those without (P = .014). Both non-pharmacological and pharmacological OH treatment strategies were associated with symptomatic improvement at follow-up.

Conclusions: In PD individuals referred to tertiary settings, tilt-table testing more frequently disclosed dOH compared to age-matched individuals without parkinsonism. In PD, dOH is mainly driven by a progressive orthostatic systolic BP fall, increasing the risk of syncope. Given its prevalence and the potential for effective treatment, dOH should be actively screened for in clinical practice.