Abstract Body (Do not enter title and authors here): Introduction
Iron deficiency is a well-established comorbidity for heart failure (HF), but its role in subclinical stages of HF remains unclear. This study aimed to examine the association between iron deficiency and pre-HF in a diverse Hispanic/Latino cohort in the United States.

Methods
Iron deficiency was assessed at baseline in the Hispanic Community Health Study (HCHS/SOL, 2008-2011) using a composite definition: ferritin <30 ng/dl and transferrin saturation <30% if the estimated glomerular filtration rate (eGFR) >60ml/min/1.73m²; or ferritin <300ng/dl and transferrin saturation <30% if eGFR <60ml/min/1.73m², for both sexes. Echocardiographic outcomes were measured at two visits in the Echocardiographic Study of Latinos (ECHO-SOL) ancillary study (N=1643). Prevalent pre-HF at Visit 1 (2011–2014) was defined as ≥1 abnormal echocardiographic parameter: LVEF <50%, global longitudinal strain > -15%, diastolic dysfunction ≥ grade 1, left ventricular mass index >115 in men/>95 in women, relative wall thickness >0.42. Incident pre-HF was defined at Visit 2 (2015–2018) among participants without pre-HF at baseline (n=588). Multivariable logistic regression models adjusted for sociodemographic and clinical covariates. Stratified analyses of iron deficiency and prevalent pre-HF were conducted by CKD categories defined using eGFR (MDRD equation). All analyses accounted for complex survey design.

Results
Iron deficiency was present in n = 198 participants (mean age 56.1, female 82.1%). Participants with iron deficiency had higher proportions of prevalent pre-HF compared to those without (75.0% vs. 66.2%, p = 0.03) but no significant differences were seen among proportions of incident pre-HF (56.5% vs. 55.0%, p = 0.84). Iron deficiency increased the odds for prevalent pre-HF by 64% after full adjustments (OR 1.64, 95% CI 1.05–2.55, p = 0.03). In stratified models, iron deficiency was associated with almost a threefold increase in the odds of prevalent pre-HF among participants with mild CKD (OR 2.79, 95% CI 1.27–6.16) even after full adjustments, but not in those with normal or ≥ moderate CKD, Table 1. No significant association was found between iron deficiency and incident pre-HF (p = 0.84), Table 2.

Conclusions
Iron deficiency is independently associated with prevalent but not incident pre-HF in Hispanic/Latino adults, particularly in those with mild CKD. These findings highlight the importance of early iron status assessment in HF prevention strategies.