Supine orthostatic hypotension better predicts falls and orthostatic symptoms compared to seated orthostatic hypotension, suggests a new research presented at the recent American Heart Association (AHA) Hypertension Scientific Sessions 2021.

The study included 522 participants, mean age 76 years, from the STURDY (Study to Understand Fall Reduction and Vitamin D) trial, which examined the effects of vitamin D3 dose on falls in older adults aged 70 years and above at higher risk of falls.

Orthostatic hypotension was assessed from seated to standing position and from supine to standing position. A fall in systolic BP of at least 20 mm Hg or diastolic BP of at least 10 mm Hg was taken as orthostatic hypotension.

The mean BP at baseline was 129/68 mmHg, which increased 3.4/2.6 mm Hg after sitting, but decreased -3.7/-0.7 mm Hg in the lying down position. Out of the total 953 OH assessments, OH was detected in 14.8% measured in the supine position, but in only 2.2% when measured in the seated position.

Compared to seated orthostatic hypotension, supine measurements were found to better predict falls;  HR 1.60 (95% CI: 0.98, 2.61; P=0.06) vs seated OH HR 0.70 (95% CI: 0.30, 1.60; P=0.39). A greater association with orthostatic symptoms (such as  fainting, blacking out, seeing spots, room spinning, and headache) was also observed for supine orthostatic hypotension.

The study found no association of vitamin D supplementation with orthostatic hypotension or falls as has been hypothesized.

Orthostatic hypotension is generally measured by assessing change in BP from seated to standing position. However, this study has demonstrated that supine orthostatic hypotension predicted the risk of falls better. Hence, older adults at risk for falls undergoing assessment for OH should lie supine AND  change from supine to standing, suggest the study authors.

References

1. Juraschek SP, et al. Hypertension Scientific Sessions 2021: Oral abstract 49. Presented September 29, 2021.
2. Supine tops seated for orthostatic hypotension assessment - Medscape - Oct 04, 2021.