The relationship between red cell distribution width, serum calcium ratio, and in-hospital mortality among patients with acute respiratory failure: A retrospective cohort study of the MIMIC-IV database

To investigate the impact of RDW/CA (the ratio of red cell distribution width to calcium) on in-hospital mortality in patients with acute respiratory failure (ARF). This retrospective cohort study analyzed the data of 6981 ARF patients from the Medical Information Mart for Intensive Care (MIMIC-IV) database 2.0. Critically ill participants between 2008 and 2019 at the Beth Israel Deaconess Medical Center in Boston. The primary outcome of interest was in-hospital mortality. A Cox proportional hazards regression model was used to determine whether the RDW/CA ratio independently correlated with in-hospital mortality. The Kaplan-Meier method was used to plot the survival curves of the RDW/CA. Subgroup analyses were performed to measure the mortality across various subgroups. After adjusting for potential covariates, we found that a higher RDW/CA was associated with an increased risk of in-hospital mortality (HR = 1.17, 95% CI: 1.01-1.35, P = .0365) in ARF patients. A nonlinear relationship was observed between RDW/CA and in-hospital mortality, with an inflection point of 1.97. When RDW/CA ≥ 1.97 was positively correlated with in-hospital mortality in patients with ARF (HR = 1.554, 95% CI: 1.183-2.042, P = .0015). The Kaplan-Meier curve indicated the higher survival rates for RDW/CA < 1.97 and the lower for RDW/CA ≥ 1.97 after adjustment for age, gender, body mass index, and ethnicity. RDW/CA is an independent predictor of in-hospital mortality in patients with ARF. Furthermore, a nonlinear relationship was observed between RDW/CA and in-hospital mortality in patients with ARF.

ANALYSIS OF THE RELATIONSHIP BETWEEN EARLY SERUM PHOSPHATE LEVELS AND SHORT-TERM MORTALITY IN SEPTIC PATIENTS: A RETROSPECTIVE STUDY BASED ON MIMIC-IV

ABSTRACT

Objective: The aim of the study is to explore the impact of early serum phosphate levels on the prognosis of critically ill patients with sepsis. Methods: In this retrospective large cohort study, data of patients with sepsis were obtained from the Medical Information Mart for Intensive Care IV database. Patients were retrospectively divided into a control group and three study groups according to their daily serum phosphate levels within 2 days of intensive care unit (ICU) admission. A Cox regression model was used to evaluate the association between serum phosphate levels and 28-day morbidity. Results: This study included 9,691 patients diagnosed with sepsis. During the first 2 days of ICU admission, patients with hyperphosphatemia in either of the 2 days had higher 28-day mortality, while patients in the hypophosphatemia group had lower 28-day mortality (first day, 32.9% vs. 16.3%; second day, 36.3% vs. 14.7%). After adjusting for potential confounders, hyperphosphatemia was significantly associated with 28-day mortality; however, only hypophosphatemia on the second day was independently associated with reduced 28-day mortality. After stratification in the hypophosphatemia group, subgroup analysis showed that only the association between the mild hypophosphatemia group and 28-day mortality reached statistical significance (hazard ratio = 0.76, 95% CI = 0.65-0.89, P = 0.001). Conclusions: Mild hypophosphatemia might improve the short-term prognosis of patients with sepsis, and hyperphosphatemia is an independent risk factor for the outcomes of septic patients. After ICU admission, the serum phosphate levels on the second day had a better independent correlation with 28-day mortality, which prompted us to reconsider the optimal timing of phosphate evaluation.