Independent effects of the hemoglobin-to-red blood cell distribution width ratio on 180-day mortality in critically ill patients with Gastrointestinal bleeding: analysis from the MIMIC-IV database.

BACKGROUND

Gastrointestinal bleeding (GIB) is associated with high mortality rates among critically ill patients. The hemoglobin-to-red blood cell distribution width ratio (HRR) has recently emerged as a potential prognostic marker in various clinical settings. However, the association between HRR and prognosis in critically ill patients with GIB is unclear.

METHODS

We conducted a retrospective cohort study using the MIMIC-IV database (version 2.2). Patients diagnosed with GIB were included based on predefined criteria. The HRR was calculated as the ratio of hemoglobin to red blood cell distribution width. Kaplan-Meier curves and multivariate Cox regression models assessed the association between HRR and 180-day mortality. Restricted cubic spline curves were employed to evaluate the nonlinear relationship between HRR and mortality. Additionally, a segmented regression model was constructed to determine the threshold effect in nonlinearity. Subgroup analyses were performed to assess the consistency of the relationship between HRR and 180-day mortality across different patient populations.

RESULTS

A total of 2,346 patients met the inclusion criteria. Higher HRR was independently associated with reduced 180-day all-cause mortality (adjusted HR, 0.15; 95% CI, 0.07-0.31; P < 0.001). Non-linear associations were observed using restricted cubic splines (P for overall < 0.001, P for non-linearity = 0.002). When HRR was less than 0.81, each unit increase in HRR was associated with a 90% reduction in 180-day mortality among patients with GIB (HR, 0.10; 95% CI, 0.04-0.24; P < 0.001). Subgroup analyses demonstrated that the association between HRR and 180-day mortality was consistent across all subgroups.

CONCLUSION

HRR exhibits a significant nonlinear negative association with 180-day mortality in critically ill patients with GIB. This association was consistent across multiple subgroups, suggesting that HRR may serve as a simple and effective prognostic biomarker in patients with GIB.