Status nutricional de selênio, biomarcadores clínicos e inflamatórios de pacientes hospitalizados com Covid-19 moderada e grave

Abstract

COVID-19 has become one of the most serious pandemics in world history. It is a disease that triggers an exacerbated inflammatory cascade, which demonstrates the relevance of specific micronutrients in attenuating clinical picture. Selenium has gained prominence due to its association with reduction in the incidence of infections, immune and antioxidant improvement, in addition to its contribution to the proper functioning of the thyroid. In Brazil, there are no studies that evaluated the relationship between selenium status in COVID-19 in hospitalized patients and its association with markers of clinical severity, inflammation and thyroid function. Based on this, the study aimed to evaluate inflammatory and clinical biomarkers as well as thyroid complications that are related to urinary selenium status in hospitalized patients with moderate and severe COVID-19. It is a cross-sectional study that is aligned with another cohort, descriptive, observational and prospective study. The sample consisted of 121 patients with COVID-19 that were admitted to the nursing units. Critical patients with a history of thyroid disease, pregnant women and those who used medications that interfere with thyroid metabolism or the ones that have been using iodinated contrast in the last 6 months were excluded from the study. All of the patients in the study had a confirmed diagnosis of SARS-CoV-2 through quantitative reverse transcriptase polymerase chain reaction of respiratory tract samples. Patients underwent measurement of hormonal and immunological biomarkers (thyroid thyroid-stimulating hormone, free triiodothyronine, free thyroxine, reverse triiodothyronine, thyroglobulin, Interleukin 6, D-dimer, C-reactive protein, lactic dehydrogenase). Urine samples were collected within the first 48 hours for selenium analysis. For clinical severity, NEWS2 and qSOFA scores were used, and body mass index was used for nutritional assessment. Patients were divided into tertiles. Mean total urinary selenium was 33.8 (SD=18.8 μg/L), median 31.0 μg/L. 94.2% of the patients had normal urinary selenium, considering the normal range for healthy individuals. Most patients who presented urinary selenium in the lowest tertile were elderly (N=22; 55%). Obese patients, on the other hand, had higher levels of selenium in tertile 3 (N=28; 78.6%). Regarding the Non Thyroid Disease Syndrome, 5.7% of the patients presented alteration (p=0.008). Other comorbidities and severity scores were indifferent in the population and between groups. A negative correlation was observed between urinary selenium and all inflammation marker proteins interleukin 6, d-dimer and C-reactive protein (ρ <0; p>0.05), except with lactic dehydrogenase, though without statistical significance (ρ=0.085; p>0.05). Patients, in general, had urinary selenium excretion levels, considering the normal range for a healthy population. In obese population, the result was controversial, given the alterations in Se metabolism in situations of adiposopathy, hepatic and renal dysfunction. A high prevalence of elderly people with lower levels of Se was found, which reveals the vulnerability of this population. No statistically significant differences wereobserved between clinical severity scores, inflammatory biomarkers and urinary selenium, despite studies showing lower levels of selenium in other serious diseases. Non-Thyroid Disease Syndrome was the most significant thyroid complication in the study.