Serum chloride level has clinical significance in the prognosis of heart failure. Little is known regarding the association between serum chloride levels and in-hospital mortality in patients with heart failure.

This retrospective study used clinical data obtained from the Medical Information Mart for Intensive Care Database. The study cohort comprised patients who were categorized on the basis of their serum chloride levels, and the primary endpoint was in-hospital mortality. To assess the impact of serum chloride levels at the time of intensive care unit admission on in-hospital mortality, we used various statistical approaches, including multivariable logistic regression models, a generalized additive model, and a two-piecewise linear regression model. In addition, subgroup analysis was conducted to examine the robustness of the main findings.

This study comprised 15,983 participants. When compared with the reference group (Q5), the groups with the highest (Q7) and lowest (Q1) blood chloride levels exhibited increased in-hospital mortality, with fully adjusted odds ratios (ORs) of 1.36 [95% confidence interval (CI): 1.08-1.71] and 1.25 (95% CI: 1-1.56), respectively. A U-shaped relationship was observed between blood chloride levels and in-hospital mortality, with the lowest risk observed at a threshold of 105.017 mmol/L. The effect sizes and corresponding CIs below and above the threshold were 0.969 (95% CI: 0.957-0.982) and 1.039 (95% CI: 1.002-1.076), respectively. Stratified analyses demonstrated the robustness of this correlation.

The relationship between serum chloride levels and in-hospital mortality in patients with heart failure was U-shaped, with an inflection point of 105.017 mmol/L.

血清氯水平对心力衰竭的预后具有临床意义。关于心力衰竭患者血清氯水平与院内死亡率之间的关系知之甚少。

这项回顾性研究使用了从重症监护医疗信息市场数据库获得的临床数据。研究队列包括根据血清氯化物水平进行分类的患者，主要终点是院内死亡率。为了评估入住重症监护病房时血清氯化物水平对院内死亡率的影响，我们使用了各种统计方法，包括多变量逻辑回归模型、广义加性模型和两段线性回归模型。此外，还进行了亚组分析以检验主要研究结果的稳健性。

这项研究共有 15,983 名参与者。与参考组 (Q5) 相比，血氯水平最高 (Q7) 和最低 (Q1) 的组表现出院内死亡率增加，完全调整的比值比 (OR) 为 1.36 [95% 置信区间 (CI) ): 1.08-1.71] 和 1.25 (95% CI: 1-1.56)。血氯水平与院内死亡率之间存在 U 形关系，在阈值 105.017 mmol/L 时观察到的风险最低。低于和高于阈值的效应大小和相应的 CI 分别为 0.969 (95% CI: 0.957-0.982) 和 1.039 (95% CI: 1.002-1.076)。分层分析证明了这种相关性的稳健性。

心力衰竭患者血清氯水平与院内死亡率呈U型关系，拐点为105.017 mmol/L。