High hemoglobin-to-red cell distribution width ratio reduces adverse events in patients with pacemaker implantation.

Background: The prognostic significance of the hemoglobin-to-red blood cell distribution width (Hb/RDW) ratio in patients undergoing pacemaker implantation (PMI) remains uncertain. Our study aimed to explore the prospective relationship between the Hb/RDW ratio and the risk of major cardiovascular events (MCEs) in Chinese patients with PMI.

Methods: A total of 595 patients with permanent PMI were enrolled. Patients were divided into the high-Hb/RDW (≥ 9.1 g/L per percent) and the low-Hb/RDW (< 9.1 g/L per percent) groups according to the levels of the Hb/RDW ratio using the receiver operating characteristic curve. The primary outcome was the composite MCEs including heart failure hospitalization, myocardial infarction, stroke, and all-cause death, presented as hazard ratios (HR) with 95% confidence intervals (CI) estimated by the Cox Proportional Hazards models, propensity score (PS) adjusted, and inverse probability weighting (IPW) analyses, respectively.

Results: During the median 2-year follow-up period, 95 (16%) MCEs were identified among the 595 patients with PMI Patients with a high Hb/RDW ratio exhibited a lower risk of MCEs compared to those with a low Hb/RDW ratio (adjusted HR: 0.456; 95% CI: 0.376-0.848). In additional analyses with different statistical models, the multivariate-adjusted HR was 0.592 (95% CI: 0.380-0.920) for the PS-adjusted analysis and 0.444 (95% CI: 0.271-0.729) for the IPW, respectively. There were no interactions between subgroups and Hb/RDW in our analysis.

Conclusion: High levels of the Hb/RDW ratio were linked to a lower risk of composite MCEs. The Hb/RDW ratio was a better predictor of MCEs than Hb or RDW alone.