ABSTRACT
INTRODUCTION: Heart failure (HF) is a growing public health issue; its risk factors include inappropriate dietary intake of microelements such as iodine, selenium, zinc and iron, which may lead to thyroid dysfunction. OBJECTIVE: This study aimed to assess the correlation among the functional class stages of patients with HF, iodine, selenium, iron and zinc levels with the presence of thyroid dysfunction. METHODOLOGY: One hundred nine patients from the HF outpatient clinic of the Clinics Hospital of Ribeirão Preto whose blood and urine were collected for micronutrient analysis and laboratory tests were selected. The subjects' weight and height were also measured to calculate their BMI. First, a descriptive analysis of the data was made into tables, and then statistical analyses were done at a 5% significance level (p < 0.05). RESULTS: Most patients whose data was analysed were elderly and overweight. Excess ioduria, serum selenium and zinc, erythrocyte zinc and deficiency in serum iron and erythrocyte selenium were observed. The prevalence of thyroid dysfunction was 8.3%. Multivariate logistic regression verified that thyroid dysfunction increases the chance of classification in functional class III or IV (p = 0.015; OR = 8.72) by 8.7 times; each year of age increases the chance by 4.6% of classification in functional class III or IV (p = 0.008; odds ratio [OR] = 1.05), and each unit of BMI increases the chance of classification in functional class III or IV by 9.2% (p = 0.028; OR = 1.09). CONCLUSION: Patients with HF were deficient in serum iron and erythrocyte selenium. No connection was found between hypothyroidism and mineral deficiency, which seems to be related more to the severity of the disease than to the micronutrient nutritional profile.