Background: Low systolic blood pressure (SBP) values are associated with an increased risk of cardiovascular events, giving rise to the so-called J-curve phenomenon. We assessed the association between on-treatment SBP levels, cardiovascular events, and all-cause mortality in patients randomized to different SBP targets.

Methods: Data from 2 large randomized trials that randomly allocated hypertensive patients at high risk for cardiovascular disease to intensive (SBP<120 mm Hg) or conventional (SBP<140 mm Hg) treatment were pooled and harmonized for outcomes and follow-up duration. Using natural cubic splines, we plotted the hazard ratio for all-cause mortality and cardiovascular events against the mean on-treatment SBP per treatment group.

Results: The pooled data consisted of 194 875 on-treatment SBP measurements in 13 946 patients (98.9%). During a median follow-up of 3.3 years, cardiovascular events occurred in 1014 patients (7.3%), and 502 patients died (3.7%). For both blood pressure targets, an identical shape of the J curve was present, with a nadir for cardiovascular events and all-cause mortality just below the SBP target. Patients in the lowest SBP stratum were older, had a higher body mass index, smoked more often, and had a higher frequency of diabetes mellitus and cardiovascular events.

Conclusions: Low on-treatment SBP levels are associated with increased cardiovascular events and all-cause mortality. This association is independent of the attained blood pressure level because the J curve aligns with the SBP target. Our results suggest that the benefit or risk associated with intensive blood pressure–lowering treatment can be established only via randomized clinical trials.

Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01206062 and NCT00000620.

中文翻译：

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随机分配给不同收缩压目标的患者的J曲线

背景：低收缩压（SBP）值会增加心血管事件的风险，从而引起所谓的J曲线现象。我们评估了随机分配到不同SBP目标患者的治疗中SBP水平，心血管事件和全因死亡率之间的关联。

方法：收集来自2个大型随机试验的数据，这些数据随机将高心血管病风险的高血压患者分配为强化治疗（SBP <120 mm Hg）或常规治疗（SBP <140 mm Hg），并针对结果和随访时间进行协调。使用天然三次样条，我们绘制了每个治疗组的全因死亡率和心血管事件的危险比与平均治疗中SBP的关系。

结果：汇总的数据包括对13 946例患者进行治疗时194 875例SBP测量值（98.9％）。在3.3年的中位随访期间，有1014例患者发生了心血管事件（7.3％），有502例患者死亡（3.7％）。对于这两个血压目标，均呈现出相同的J曲线形状，其中心血管事件和所有原因的死亡率最低，刚好低于SBP目标。SBP层最低的患者年龄较大，体重指数较高，吸烟频率较高，糖尿病和心血管事件的发生频率较高。

结论：治疗中SBP水平低与心血管事件和全因死亡率增加有关。这种关联与获得的血压水平无关，因为J曲线与SBP目标对齐。我们的结果表明，只有通过随机临床试验才能确定与强化降压治疗有关的益处或风险。

临床试验注册： URL：https : //www.clinicaltrials.gov。唯一标识符：NCT01206062和NCT00000620。