Abstract Body: Background: Improving hypertension control is an important global health priority. We aimed to study the effects of hypothetical interventions on systolic blood pressure (SBP) on mortality risk at the population level.
Methods: We estimated the relationship between SBP and all-cause mortality in adults aged 45 years and older from the China Health and Retirement Longitudinal Study and compared the mortality reductions associated with lowering SBP to different hypothetical targets (120, 130, 140, 150 mm Hg). Using the parametric g-computation modeling technique, we estimated the mean blood pressure reduction required to achieve each target, the share of the population in need of management, and the number needed to treat (NNT) to avert one death under different hypothetical population-wide scale-up scenarios.
Results: Among 12355 participants, 1203 died over 7-year follow-up. We found a weak, non-linear relationship between SBP and mortality, with larger incremental mortality benefits at higher SBP values: reducing SBP from 160 mm Hg to 120 mm Hg was associated with a relative risk of mortality of 0.75 (95% CI 0.65 to 0.86). At the population level, reducing SBP to 120 mm Hg among all those with a starting SBP of more than 120 mm Hg (120 mm Hg scenario) was associated with 13.7 deaths averted per 1000 population (95% CI -19.3 to -8.1), compared with 3.8 deaths averted per 1000 population (95% CI -6.0 to -1.6) associated with reducing SBP to 150 mm Hg among all those with a starting SBP of more than 150 mm Hg (150 mm Hg scenario). However, there were large differences between scenarios in the proportion of the population that would require treatment, ranging from 64.3% (95% CI 63.4 to 65.1) in the 120 mm Hg scenario to 16.7% (6.0 to 17.3) in the 150 mm Hg scenario. To achieve the target, the 120 mm Hg scenario required a mean shift of -14.4 mm Hg in SBP (95% CI -14.7 to -14.1) compared with a -2.9 mm Hg mean change (-3.0 to -2.7) for the 150 mm Hg scenario. Based on the ratio of number of deaths averted to the proportion requiring treatment, the 150 mm Hg scenario had the smallest NNT (n=44), followed by the 120 mm Hg scenario (n=47), the 140 mm Hg scenario (n=49), and the 130 mm Hg scenario (n=51).
Conclusions: These findings highlight the possible substantial benefits of reducing blood pressure. We find that scaling up management based on a 150 mm Hg target is more efficient in terms of the NNT compared with strategies to reduce SBP to lower levels.