Re: Revisiting the association of blood pressure with mortality in oldest old people in China: community based, longitudinal prospective study
Lv et al. (1) revisit the U-shaped association between blood pressure and mortality in very old people. While previously established in cohort studies (2), Lv et al. (1) confirm this association in Chinese participants using an impressively large and representative sample.
We caution that observational data have important limitations when drawing conclusions concerning clinical policy and decision-making. Reverse causation may apply if proximity to death influences blood pressure level, as observational studies lack a consistent start time for observation and may include, in different groups, fit individuals and frailer people closer to the end-of-life. We previously reported a terminal decline in blood pressure at the end-of-life, which might contribute to the reported association between lower SBP levels and higher mortality (3).
In contrast to observational data, the SPRINT trial reported substantial benefits from using more intensive SBP treatment targets (< 120 mmHg) in older people (4). Nevertheless, questions remain concerning the generalisability of these findings, especially in frail patients. Treatment for hypertension may increase the incidence of falls in older adults (5).
While we agree with Lv et al. (1) that better evidence is needed for blood pressure management at advanced age, this should be drawn from randomised studies where possible.
1. Lv Yue-Bin, Gao Xiang, Yin Zhao-Xue, Chen Hua-Shuai, Luo Jie-Si, Brasher Melanie Sereny et al. Revisiting the association of blood pressure with mortality in oldest old people in China: community based, longitudinal prospective study BMJ 2018;361 :k2158.
2. Molander L, Lövheim H, Norman T, Nordström P, Gustafson Y. Lower systolic blood pressure is associated with greater mortality in people aged 85 and older. J Am Geriatr Soc. 2008;56:1853–1859.
3. Ravindrarajah R, Hazra NC, Hamada S, Charlton J, Jackson SH, Dregan A, et al. Systolic blood pressure trajectory, frailty and all-cause mortality over 80 years of age. Cohort study using electronic health records. Circulation. 2017 Jun 13;135(24):2357-2368
4. Williamson JD, Supiano MA, Applegate WB, et al. Intensive vs Standard Blood Pressure Control and Cardiovascular Disease Outcomes in Adults Aged ≥75 YearsA Randomized Clinical Trial. JAMA.2016;315(24):2673–2682. doi:10.1001/jama.2016.7050
5. Tinetti ME, Han L, Lee DSH, et al. Antihypertensive Medications and Serious Fall Injuries in a Nationally Representative Sample of Older Adults. JAMA internal medicine. 2014;174(4):588-595. doi:10.1001/jamainternmed.2013.14764.
Competing interests: No competing interests