Validation of orthostatic hypotension in MDS diagnostic criteria for multiple system atrophy

Purpose: In 2022, the Movement Disorder Society (MDS) proposed revised diagnostic criteria for multiple system atrophy (MSA), defining neurogenic orthostatic hypotension (OH) as a reduction in systolic/diastolic blood pressure exceeding 20/10 mmHg. This study aimed to validate the sensitivity of the MDS OH criteria and to compare the extent and pattern of OH across synucleinopathies, including Parkinson disease (PD), dementia with Lewy bodies (DLB), and pure autonomic failure (PAF). Methods: The medical records of 451 patients were retrospectively reviewed, including those with clinically probable MSA (n=107), PD (n=223), DLB (n=89), and PAF (n=32). OH was assessed using both the MDS and Gilman criteria for probable MSA. Systolic blood pressure overshoot following head-up tilting was also evaluated. Results: Among patients with MSA, neurogenic OH was identified in 39.3% using the Gilman criteria and in 64.5% using the MDS criteria (p<0.001). OH based on the MDS criteria was also detected in PD (39.0%), DLB (67.4%), and PAF (87.5%). Systolic blood pressure overshoot was observed in patients with MSA (6.5%), PD (12.6%; p=0.097 versus MSA), DLB (21.3%; p=0.002), and PAF (28.1%; p<0.001). Conclusions: The MDS criteria more sensitively detect neurogenic OH in MSA compared with the Gilman criteria. Although OH is common across synucleinopathies, the lower frequency of systolic blood pressure overshoot in MSA may assist in its differentiation, potentially reflecting less prominent postganglionic autonomic impairment.