Selenium status and heart failure: associations with clinical and nutritional parameters and impact on clinical outcomes
Heart failure; selenium; biomarkers; survival analysis
Selenium deficiency have been a frequent finding in individuals with heart failure (HF), but there are gaps in the literature on the factors associated with this condition. Additionally, the impact of selenium status on mortality and hospitalization outcomes in this population has been investigated. This study aimed to evaluate the selenium status and its associations with clinical and nutritional parameters, as well as the impact on clinical outcomes of individuals with HF followed up on an outpatient basis with up to 36 months of follow-up. We studied 80 patients diagnosed with HF, adults and older people of both sexes, followed at the Interprofessional Outpatient Clinic for Heart Failure at the Hospital Universitário Onofre Lopes. Plasma selenium concentrations, dietary selenium intake, sociodemographic, anthropometric, clinical, biochemical parameters, and clinical outcomes (hospitalization and mortality) were evaluated. Plasma selenium was measured by inductively coupled plasma mass spectrometry (ICP-MS). Independent variables were analyzed according to tertiles of plasma selenium concentrations. Multiple linear regression models were run using the stepwise method to determine associations between plasma selenium and other variables. Analysis of the ROC curve was performed to define a cut-off point for plasma selenium values with greater sensitivity and specificity for clinical trials of mortality and hospitalization. Relationships between selenium status and clinical analyzes were observed using Cox Regression. Outpatients with HF were predominantly male (61.3%), and overweight (52.5%). The most frequent type of HF was reduced ejection fraction (HFrEF) (53.8%), non-ischemic etiology (55.0%), and functional class I (71.2%). A significant percentage of patients had plasma selenium concentrations within the reference range (91.2%) and the prevalence of inadequate consumption of the element was 29.12%. In plasma selenium T1, lower concentrations of the following variables were observed, compared to the other tertiles: aspartate aminotransferase (T1<T2 and T3, p=0.003 and p=0.015, respectively), alanine aminotransferase (T1<T2 and T3, p =0.026 and p=0.027, respectively) and albumin (T1<T3, p=0.01). A significant increase in ferritin was observed at T2 to T3 (p=0.001). Urea values were higher at T3 compared to T2 and T1 (p=0.047 and p=0.024). Regression analysis indicated associations between albumin (β=0.113, p<0.001; R²=0.291) and triglycerides (β=0.0002, p<0.021, R²=0.376) with plasma selenium. Plasma selenium cutoff ≥ 83.80 μg/L obtained for subjects was associated with increased risk of all-cause mortality (HR 20.40; p=0.018) and hospitalizations (HR=3.62; p=0.049). In conclusion, it was observed that most outpatients with HF had plasma selenium values within the normal range, highlighting albumin and triglycerides as independent predictors of this variable. In addition, the plasma selenium cut-off point of 83.80μg/L was related to an increased risk of unfavorable clinical outcomes in this population.