Serum iron levels predict mortality risk in hypertensive patients: A prospective cohort study

Background and aim

This study aimed to investigate the relationship between serum iron levels and mortality risk in hypertensive patients.

Methods and results

A total of 15,181 hypertensive patients were included and stratified into four groups based on serum iron levels (Quartile 1 to Quartile 4). Patients were followed for an average of 85.24 ± 1.16 months. The proportions of all-cause mortality across Quartiles 1 through 4 were 16.96 %, 14.65 %, 13.47 %, and 12.15 %, respectively (p < 0.001), while the cardiovascular mortality rates were 5.06 %, 3.67 %, 3.46 %, and 2.84 %, respectively (p < 0.001). After adjusting for confounders, the risks of all-cause and cardiovascular mortality were significantly lower in Quartile 2 (hazard ratio [HR] = 0.80, p = 0.060; HR = 0.57, p = 0.004), Quartile 3 (HR = 0.76, p = 0.050; HR = 0.58, p = 0.010), and Quartile 4 (HR = 0.64, p < 0.001; HR = 0.45, p < 0.001) compared to Quartile 1. Restricted cubic spline regression revealed a significant negative association between serum iron levels and the risks of all-cause and cardiovascular mortality. Additionally, mediation analysis showed that body mass index (BMI), serum creatinine, and lipid profile partially mediated the effect of serum iron on mortality risk.

Conclusions

Elevated serum iron levels were related to lower risks of mortality in hypertensive patients. BMI, serum creatinine, and lipid profile mediated this relationship, suggesting a potential interplay between metabolic and renal factors in modulating the effect of serum iron on mortality.