Prospective, single-center study of 114 idiopathic PD patients found orthostatic hypotension in 28% (detected by head-up tilt testing), with prevalence rising sharply with disease duration and Hoehn & Yahr stage and including asymptomatic cases.

The paper has moderate translational value: it supports routine HUTT screening to prevent falls and to stratify or monitor patients for symptomatic autonomic therapies and clinical trials, but offers limited mechanistic or novel therapeutic-target insights for disease-modifying drug discovery.

INTRODUCTION: Parkinson's disease (PD) is a neurodegenerative disorder, affecting individuals aged 60 and older, with rapidly increasing prevalence in aging populations, particularly in India. Apart from classical motor symptoms, nonmotor symptoms, particularly orthostatic hypotension (OH), significantly affect the quality of life, increasing the fall risk that contributes to increasing morbidity and mortality. This single-center, prospective, cross-sectional observational study evaluates OH, a key cardiovascular autonomic dysfunction, in idiopathic PD patients using the head-up tilt test (HUTT) to assess its prevalence and correlation with disease duration and severity. Conducted from July 2023 to June 2024 at the Department of Neurology, Indira Gandhi Government General Hospital and Post Graduate Institute, Puducherry, India, the study enrolled 114 patients diagnosed according to UK Brain Bank criteria, excluding confounders such as diabetic neuropathy or cardiovascular comorbidities. METHODS: Patients underwent detailed clinical evaluation, demographics, PD duration, autonomic symptom history, and Modified Hoehn and Yahr staging, and the HUTT was commenced at 60° after 30 minutes of supine rest. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure, and heart rate were obtained every five minutes before tilt; one, three, and five minutes during tilt; and one minute after tilt, as indicated for patient safety. OH was defined as a drop in SBP ≥20 mmHg and/or DBP ≥10 mmHg within three to five minutes. Data analysis used Statistical Package for the Social Sciences version 20 (IBM Corp., Armonk, NY) with chi-square test, analysis of variance, t tests, and Pearson correlation (p < 0.05 significant). Ethical approval was obtained from the institution's ethics committee, and informed consent was obtained to ensure confidentiality. RESULTS: The mean age was 65 ± 11.19 years, 62.28% were male, and the mean disease duration was 2.75 ± 1.93 years. OH prevalence was 28% (32/114 patients). No gender association was observed (p = 0.180), but strong links with duration (p < 0.00001; 0% in less than one year, 100% in greater than five years) and H&Y stage (p < 0.00001; 7.4% stage 1, 100% stage 3) were noticed. Disease duration positively correlated with H&Y stage (r = 0.459, p = 0.0001). DISCUSSION: OH increases progressively with PD duration and motor severity, reflecting autonomic neurodegeneration independent of dopaminergic loss, consistent with prior studies. The HUTT's sensitivity detected asymptomatic cases, which are vital for fall mitigation. HUTT proved superior to static measures for early detection. Limitations of the study include a single-center design and the absence of a control group. Routine screening via HUTT is recommended for advanced PD to prevent falls/syncope via interventions (e.g., hydration and midodrine). CONCLUSION: OH affects 28% of idiopathic PD patients, strongly tied to duration and H&Y stage; HUTT enables proactive management to enhance the quality of life.