Is baseline orthostatic hypotension associated with a decline in global cognitive performance at 4-year follow-up? Data from TILDA (the irish longitudinal study on ageing)

Abstract

Background-It is postulated that orthostatic hypotension (OH), a reduction in blood pressure (≥20/10 mm Hg) within 3 minutes of standing, may increase cognitive decline because of cerebral hypoperfusion. This study assesses the impact of OH on global cognition at 4-year follow-up, and the impact of age and hypertension on this association. Methods and Results-Data from waves 1 and 3 of TILDA (The Irish Longitudinal Study on Ageing) were used. Baseline blood pressure response to active stand was assessed using beat-to-beat blood pressure monitoring. Two measures of OH were used— at 40 seconds (OH40) and 110 seconds (OH110). Global cognition was measured using the Montreal Cognitive Assessment. Mixed-effects Poisson regression assessed whether baseline OH was associated with a decline in global cognition at 4-year followup. The analysis was repeated, stratifying by age (age 50–64 years and age ≥65 years), and including an interaction between OH and hypertension. Baseline OH110 was associated with an increased error rate in Montreal Cognitive Assessment at follow-up (incident rate ratio 1.17, P=0.028). On stratification by age, the association persists in ages 50 to 64 years (incident rate ratio 1.25, P=0.048), but not ages ≥65 years. Including an interaction with hypertension found those with co-existent OH110 and hypertension (incident rate ratio 1.27, P=0.011), or OH40 and hypertension (incident rate ratio 1.18, P=0.017), showed an increased error rate; however, those with isolated OH110, OH40, or isolated hypertension did not. Conclusions-OH is associated with a decline in global cognition at 4-year follow-up, and this association is dependent on age and co-existent hypertension.