Clinical Correlates of the Haemoglobin to Red Cell Distribution Width Ratio in Bacterial Bloodstream Infections and Concomitant Kidney Dysfunction

Background The Haemoglobin-to-Red Cell Distribution Width ratio (Hb/RDW) is an emerging marker of inflammation and clinical risk, but its correlates in patients with bacterial bloodstream infections and kidney dysfunction remain poorly defined in low-resource settings. This study aimed to determine the clinical and laboratory correlates of the Hb/RDW ratio in patients with bacterial bloodstream infections and concomitant kidney dysfunction at Ndola Teaching Hospital. Methods We conducted a retrospective laboratory-based study of 136 patients with confirmed bacterial bloodstream infections and kidney dysfunction at a Ndola Teaching Hospital in Zambia. Multivariable linear regression was used to identify factors independently associated with the Hb/RDW ratio. Results A total of 136 patients with bloodstream infections and kidney dysfunction were included, with a median age in the older adult range; 44.9% were ≥ 60 years. Females comprised 52.9% of the cohort. Gram-negative bacteria predominated, particularly Enterobacter agglomerans (19.8%) and Escherichia coli (10.2%), while Staphylococcus aureus (18.3%) was the most common Gram-positive isolate. Multidrug-resistant organisms accounted for 61.8% of infections. In multivariable analysis, male sex was associated with lower Hb/RDW (β = −0.092, p  = 0.020), and higher eGFR was associated with higher Hb/RDW (β = 0.003, p  = 0.049). Other hematological and biochemical parameters showed no independent association. Conclusion Hb/RDW is independently associated with sex and renal function in patients with bloodstream infections and kidney dysfunction, suggesting its potential as a simple biomarker. Future studies should evaluate its prognostic value and utility in guiding early clinical interventions.