Red cell distribution width is associated with short-term mortality in critically ill patients with heart failure

Abstract

Aims: There is limited evidence for the correlation between short-term mortality and red cell distribution width (RDW) in critical patients with heart failure. Herein, a retrospective cohort study was conducted to investigate whether RDW was independently associated with short-term mortality in critically ill patients with heart failure.

Methods and results: As a retrospective cohort study, it involved a total of 9465 patients with heart failure from the MIMIC-IV database. The target-dependent and independent variables were in-hospital mortality, 90 day mortality and RDW measured at baseline, respectively. The relationship between all-cause death and baseline RDW in hospital and after 90 days of admission to ICU was evaluated by using the Kaplan-Meier plot and Cox proportional hazard analysis. The average age of participants was 74.4 (64.2, 83.5) years old, among whom about 54.6% were male. Results of the adjusted Cox proportional hazard model revealed that RDW had a positive association with both in-hospital and 90 day mortality risk after the adjustment of confounders (HR = 1.09, 95% CI: 1.04-1.15, P < 0.001; HR = 1.11, 95% CI: 1.08-1.14, P < 0.001, respectively). A non-linear relationship was found between RDW and 90 day mortality, which had a threshold of 14.96%. The effect sizes and confidence intervals below and above the threshold were 1.36 (1.14 to 1.62) and 1.09 (1.04 to 1.15), respectively. It was also found by subgroup analysis that there were stronger correlations in male and patients with normal renal function.

Conclusions: Our data suggest that the short-term mortality of critically ill patients with HF is independently predicted by RDW. At the same time, large prospective research and longer follow-up time are required to further validate the findings of this study.

Keywords: Critically ill patients with heart failure; Prognosis; Red cell distribution width.

Figure 1

Flow chart of the screening and enrolment of study participants.

Figure 2

Red blood cell distribution width measures as a function of mortality. (A) In‐hospital mortality; (B) 90 day mortality.

Figure 3

Kaplan–Meier survival curves for in‐hospital mortality and 90 day mortality. (A) In‐hospital mortality; (B) 90 day mortality.

Figure 4

Nonlinear dose–response relationship between RDW and 90 day mortality. Adjusted for age, gender, medical history, disease severity score, BMI, HR, SBP, DBP, leucocyte, haemoglobin, MCV, eGFR, potassium, calcium, and length of stay. The solid line and dashed line represent the estimated values and their corresponding 95% confidence intervals.

Figure 5

Association between RDW and in‐hospital mortality, 90 day mortality according to baseline characteristics. Each stratification adjusted for all covariants in model 4. BMI, body mass index; eGFR, estimated glomerular filtration rate; MCV, mean corpuscular volume; HGB, haemoglobin.