Blood Pressure and Survival in the Oldest Old

Abstract

OBJECTIVES: To determine the relationship between blood pressure (BP) and all‐cause mortality in subjects aged 80 and older with hypertension. DESIGN: Retrospective cohort study with 5 years of follow‐up. SETTING: Ten Veterans AFFAIRS (VA) sites. PARTICIPANTS: Four thousand seventy‐one ambulatory patients aged 80 and older with hypertension. MEASUREMENTS: The outcome measure was likelihood of survival during the follow‐up period. Vital status was obtained from VA and Social Security files. Variables collected for adjustment in Cox regression models were baseline BP, medications, demographics, diagnoses, and health‐related quality of life (HRQoL); HRQoL information was available on 1,289 subjects based on Veterans Health Study Short From‐36 (SF‐36) questionnaire scores. RESULTS: Subjects with higher BP (up to a systolic BP (SBP) of 139 mmHg and a diastolic BP (DBP) of 89 mmHg) were less likely to die during follow‐up than subjects with lower BP. After baseline adjustments, the hazard ratio for a 10‐point increase in SBP was 0.82 (95% confidence interval (CI)=0.74–0.91), up to a SBP of 139 mmHg, and for DBP was 0.85 (95% CI=0.78–0.92), up to a DBP of 89 mmHg. There was no significant association between survival and BP levels in subjects with uncontrolled hypertension. CONCLUSION: In a cohort of very old, hypertensive veterans, in subjects with controlled BPs, subjects with lower BP levels had a lower 5‐year survival than those with higher BPs. This suggests that clinicians should use caution in their approach to BP lowering in this age group.