Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
Lancet Healthy Longev. 2021 Feb;2(2):e78-e86. doi: 10.1016/s2666-7568(20)30050-7. Epub 2021 Jan 18.
Improving hypertension control is an important global health priority yet, to our knowledge, there is no direct evidence on the blood pressure (BP)-mortality relationship in sub-Saharan Africa. We investigate the BP-mortality relationship in South Africa and assess the comparative effectiveness of different care targets for clinical care and population-wide hypertension management efforts.
We use country-wide population-based longitudinal data from five waves (2008 - 2017) of the South African National Income Dynamics Study (N = 4,993). We estimate the relationship between systolic BP (SBP) and six-year all-cause mortality and compare the mortality reductions associated with lowering SBP to different targets. We then estimate the number needed to treat to avert one death (NNT) under different hypothetical population-wide scale up scenarios.
We found a weak, nonlinear, SBP-mortality relationship with larger incremental mortality benefits at higher SBP values: reducing SBP from 160 to 150 mmHg was associated with a mortality risk ratio of 0.95 (95% CI: 0.90, 0.99, p = 0.033), incrementally reducing SBP from 150 to 140 mmHg a risk ratio of 0.96 (95% CI: 0.91, 1.01, p = 0.12), with no evidence of incremental benefits of reducing BP below 140 mmHg. At the population level, reducing SBP to 150 mmHg among all those with an SBP > 150 mmHg had the lowest NNT (50) at 3.3 deaths averted (95% CI: -0.6, 0.3) per 1,000 population while requiring BP management for 16% (95% CI: 15.2, 17.3) of individuals.
The SBP-mortality association is weaker in South Africa than in high-income and many low- and middle-income countries. As such, we do not find compelling evidence in support of targets below 140 mmHg and find that scaling up management based on a 150 mmHg target is more efficient in terms of the NNT compared to strategies to reduce SBP to lower values.
改善高血压控制是全球卫生的一个重要优先事项，但据我们所知，目前在撒哈拉以南非洲地区，尚无血压（BP）与死亡率之间关系的直接证据。我们调查了南非的 BP 与死亡率之间的关系，并评估了不同的临床护理和人群高血压管理目标在临床护理中的比较效果。
我们使用来自南非国家收入动态研究（NIDS）五次波（2008-2017 年）的全国性基于人群的纵向数据（N = 4993）。我们估计收缩压（SBP）与六年全因死亡率之间的关系，并比较将 SBP 降低到不同目标值所带来的死亡率降低。然后，我们根据不同的假设人群范围扩大情景估计了避免一人死亡所需的治疗人数（NNT）。
我们发现了一种较弱的、非线性的 SBP 与死亡率之间的关系，随着 SBP 值的升高，增量死亡率的益处更大：将 SBP 从 160mmHg 降低到 150mmHg 与死亡率风险比为 0.95（95%CI：0.90，0.99，p = 0.033），将 SBP 从 150mmHg 降低到 140mmHg 的风险比为 0.96（95%CI：0.91，1.01，p = 0.12），而 SBP 降低到 140mmHg 以下没有额外的获益证据。在人群层面上，将所有 SBP > 150mmHg 的人的 SBP 降低到 150mmHg 以下，需要血压管理的人数比例最低（占 16%）（95%CI：15.2，17.3），每 1000 人中有 50 人可以避免 3.3 人死亡（95%CI：-0.6，0.3）。
在南非，SBP 与死亡率的关系比高收入国家和许多低收入和中等收入国家都要弱。因此，我们没有发现支持低于 140mmHg 目标的令人信服的证据，并且发现与将 SBP 降低到更低值的策略相比，基于 150mmHg 目标的管理扩大更为有效，NNT 较低。
