Chronic use of oral iron supplements is associated with poor clinical outcomes in patients with gram-negative bacteremia.

An unabsorbed dietary iron supplementation can modify the colonic microbiota equilibrium and favor the growth of pathogenic strains over barrier strains. Nevertheless, the impact of oral iron supplements (OIS) use on the clinical outcomes of patients with gram-negative bacteremia (GNB) has not been evaluated. To explore the impact of OIS on the outcomes of patients with GNB. A retrospective study conducted in a tertiary hospital including patients with GNB during 2011-2016. The entire cohort was divided into chronic OIS users (study group) and nonusers (control group). The two groups were compared for the study outcomes, septic shock at presentation, length of hospital stay (LOS), and short-term mortality. The study cohort included 232 patients; 44 patients in the study group and 188 in the control one. There was no any significant difference in demographic and comorbidities characteristics between the two groups. Escherichia coli comprised the majority of bacteria (69%), while the urinary tract was the main source of the bacteremia. OIS alone and after adjustment was significantly associated with septic shock at presentation (OR = 2, CI95% [1.03-5], p = 0.04 and OR = 5, CI95% [1.4-15], p = 0.01, respectively). By multivariate analysis, OIS was significantly associated with 30-day mortality (OR = 3, CI95% [1.05-7], p = 0.04), but had no impact on LOS (16 + 23 vs. 12 + 15, p = 0.9). There is a significant association between chronic OIS exposure and increased adverse outcomes in patients with GNB. These findings might have important clinical implications.