Iron Deficiency in the Presence of Anemia and Inflammation-A Sex-Specific Cross-Sectional Study

Despite frequent diagnosis of anemia of inflammation in hospitalized patients, little is known about patients' sex-specific differences in iron deficiency (ID) and its biomarkers. We aimed to study sex-specific differences in anemic patients with inflammation and their influence on iron biomarkers.

This retrospective cross-sectional study included anemic patients with inflammation (CRP > 5 mg/L) hospitalized at a Swiss tertiary referral center (01.01.2020-31.12.2023). ID was defined as ferritin-index (sTfR/log(ferritin)) ≥ 1.5. Patient characteristics were reported as medians for continuous variables and frequencies for categorical variables. Age, laboratory parameters, treatment, comorbidities, illness severity, and in-hospital mortality were analyzed. Sex-specific effects on ID biomarkers (ferritin-index, sTfR) were assessed using linear regression models.

Of 439 participants, 41.2% were female. 44.2% had ID (women: 49.7%, men: 40.3%, p = 0.052). Regression models showed no association between log(ferritin-index) and sex (coefficient 0.02, 95% CI -0.13 to 0.18, p = 0.76). Ferritin levels were lower in women (221.0 vs. 373 μg/L, p = 0.014). No sex differences in in-hospital mortality were observed (women 7.2%, men 4.3%, p = 0.21).

Despite no significant sex differences regarding ID biomarkers, treatment, illness severity, and mortality, we hypothesize that factors beyond sex, for example underlying diseases and inflammation itself, play a more prominent role in these patients' outcomes.