非外傷性くも膜下出血の集中治療室患者における赤血球分布幅と院内死亡率：コホート研究

Non-traumatic subarachnoid hemorrhage (SAH) is the predominant form of SAH and is associated with substantial in-hospital mortality. Red cell distribution width (RDW) is a novel prognostic indicator for numerous diseases. However, its association with outcomes after SAH remains uncertain. This study aimed to investigate the association between RDW and in-hospital mortality among patients with severe non-traumatic SAH and to determine the pivotal threshold for the impact of RDW on in-hospital mortality in these patients.

In total, 877 patients aged ≥ 18 years with non-traumatic SAH were identified in the MIMIC-IV (v2.2) database. The primary exposure factor was the initial RDW documented after admission. The outcome measure was the in-hospital mortality rate among patients in the intensive care unit (ICU). To evaluate the link between RDW and in-hospital mortality, a multivariate logistic regression analysis was conducted, considering possible confounding variables.

An elevated RDW was associated with increased in-hospital mortality among ICU patients with non-traumatic SAH (odds ratio [OR]: 1.36, 95 % confidence interval [CI]: 1.25-1.49). After adjustment for potential confounders, this association remained (OR = 1.22, 95 % CI: 1.09-1.37, P = 0.015). Furthermore, a nonlinear association was noted between RDW and in-hospital mortality, with no statistically significant link detected when RDW exceeded 16.12 %.

Elevated RDW was an independent risk factor for in-hospital mortality in ICU patients with non-traumatic SAH, showing a "J"-shape nonlinear association. RDW is a readily available, low-cost biomarker for clinical intervention and identification of high-risk patients with non-traumatic SAH in the ICU.