Relation between blood pressure and mortality risk in an older population: role of chronological and biological age

Background: The relation between high blood pressure (BP) and mortality risk in older individuals (above 65 years of age) is still debated. Some data suggest that this relation is inverted in certain subgroups of (biologically) older individuals. We therefore investigated whether the association between BP and mortality is dependent on chronological age and on physical and cognitive function as indicators of biological age.

Methods: The relationship between BP and all-cause mortality was investigated in 1466 older participants (aged 65 years and older; mean age 75.8 years) of the Longitudinal Ageing Study Amsterdam using multiple adjusted Cox proportional hazard models. Analyses were stratified for age, gait speed and mini mental state examination score.

Results: A total of 1008 participants died after a median (range) follow-up of 10.6 (0.2; 15.9) years. Low diastolic blood pressure (DBP) was associated with an increased all-cause mortality risk: hazard ratio (HR) of low DBP (≤70 mmHg) compared to normal DBP (71-90 mmHg) was 1.36 [95% confidence interval (CI) 1.15; 1.61]. This relation was particularly strong in the oldest old (individuals aged >80 years) and in those who had lower levels of both physical and cognitive functioning: HRs (95% CIs) of low versus normal DBP were 1.58 (1.26; 1.98) and 1.45 (1.18; 1.77), respectively.

Conclusion: In a large population-based cohort of older adults, low DBP was associated with an increased all-cause mortality risk, especially in the oldest old and in biologically old individuals.