Clinical correlates of the Haemoglobin to Red Cell Distribution Width ratio in bacterial bloodstream infections and concomitant kidney dysfunction

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, Ndola Zambia.

A total of 136 patients 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, as determined by antimicrobial susceptibility testing and classified according to the standard consensus definition. 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. Hb/RDW was independently associated with sex and renal function, suggesting its potential as a simple biomarker. Further studies are needed to confirm its prognostic and clinical utility.