Red cell distribution width and in-hospital mortality in intensive care unit patients with non-traumatic subarachnoid hemorrhage: A cohort study.

OBJECTIVE 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.

METHODS 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.

RESULTS 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 %.

CONCLUSIONS 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.