Predictors of Plasma Selenium Levels and Association with Prognosis in Outpatients with Heart Failure: a 36-Month Prospective Cohort Study.

Selenium plays a role in the context of heart failure (HF), but still, there are gaps regarding the factors associated with selenium status, as well as its association with the prognosis of HF. We aimed to investigate predictors of plasma selenium and its association with hospitalization and all-cause mortality. This prospective cohort study included 80 outpatients with HF. Non-elective hospitalization and all-cause mortality were assessed during 36 months of follow-up. The associations between plasma selenium, dietary selenium intake, and sociodemographic, clinical, and biochemical parameters were evaluated by a multiple linear regression model. The risk of these clinical outcomes was assessed with multivariate Cox regression and cubic splines analysis. Albumin (β = 0.113, p < 0.001; R = 0.291) and triacylglycerol levels (β = 0.0002, p < 0.021, R = 0.376) were predictors of plasma selenium levels. No significant associations were found between dietary selenium intake and plasma selenium tertiles with hospitalization and all-cause mortality (all p > 0.05). The cubic splines analysis revealed that both low and high selenium concentrations influence these outcomes. The predictors of plasma selenium were related to the clinical conditions of HF. Selenium in plasma should be interpreted cautiously, considering that low and high levels may be associated with risks of adverse outcomes in HF.