In patients aged ≥80 years, a decline of systolic blood pressure (SBP) in the final 2 years of life suggests that non-randomized epidemiological associations of low SBP with higher mortality may be accounted for by reverse causation, if participants with lower SBP are closer on average to the end of life. This according to a population-based cohort study of 144,403 participants aged ≥80 years in family practices from 2001 to 2014 and followed for up to 5 years. The study aimed to evaluate associations of SBP with all-cause mortality by frailty category over 80 years of age and to evaluate SBP trajectories before death. Researchers found:
- There were 51,808 deaths during follow-up.
- Mortality rates increased with frailty level and were greatest at SBP <110 mmHg.
- SBP trajectories showed an accelerated decline in the last 2 years of life.
- Relative odds of SBP <120 mmHg were higher in the last 3 months of life than 5 years previously both in treated (OR, 6.06) and untreated patients (OR, 6.31).
- There was no evidence of intensification of antihypertensive therapy in the final 2 years of life.
Ravindrarajah R, Hazra NC, Hamada S, et al. Systolic blood pressure trajectory, frailty and all-cause mortality over 80 years of age. Cohort study using electronic health records. [Published online ahead of print April 21, 2017]. Circulation. doi:10.1161/CIRCULATIONAHA.116.026687.
Most of us are familiar with the “J-curve” for hypertension, which was derived from epidemiologic studies demonstrating that mortality is high with high levels of systolic blood pressure, then decreases until a systolic of about 110-120 mmHg, and then increases again at lower levels of systolic BP, particularly in the elderly. This population-based observation has led to controversy around trying to achieve low levels of systolic BP in the elderly. Randomized trials in the elderly, including HYVET and SPRINT, have shown benefit to lowering BP in the elderly, with SPRINT showing that a target systolic BP of less than 120 mmHg in persons >75 years of age achieved a 34% lowering in cardiovascular mortality and a 33% reduction in all-cause mortality.1,2 The current study suggests that the lower end of the J-curve demonstrating increased mortality with decreasing blood pressure may not be related so much to the blood pressure, but rather to the expected decrease in systolic BP as patients become more weak and frail in the last 2 years of their lives. —Neil Skolnik, MD
- Beckett NS, Peters R, Fletcher AE, et al. Treatment of hypertension in patients 80 years of age or older. N Engl J Med. 2008;358:1887-1898. doi:10.1056/NEJMoa0801369.
- Williamson JD, Supiano MA, Applegate WB, et al. Intensive vs standard blood pressure control and cardiovascular disease outcomes. JAMA. 2016;315:2673-2682. doi:10.1001/jama.2016.7050.