The Relationship Between Vitamin D and Euthyroid Sick Syndrome in Hospitalized Solid Cancer Patients: A Retrospective Study.

Background: Euthyroid sick syndrome (ESS) is associated with cancer staging and influences prognosis in patients with lung and various other solid tumors. Although previous studies have examined the association between ESS and factors such as age, body mass index, Eastern Cooperative Oncology Group performance status (ECOG PS), hemoglobin (Hb), and acute-phase reactants in patients with solid cancers, its relationship with 25-hydroxyvitamin D [25(OH)D] remains unclear. In this study, we investigated the factors associated with ESS and explored the relationship between 25(OH)D levels and ESS in hospitalized patients with solid cancers (HSC). Methods: This retrospective study included 105 patients with HSC. Laboratory parameters were assessed using the initial blood samples collected upon hospitalization. Patients with low fT3, normal or low fT4, and normal thyrotropin (TSH) levels were classified as having ESS. Results: The overall prevalence of ESS was 37.1%. Among HSC receiving supportive care, the ESS rate was 40.3%, whereas it was lower-28.6%-in those hospitalized for chemotherapy. A statistically significant association was observed between ESS and ECOG PS, C-reactive protein (CRP), and Hb levels. Specifically, a poor ECOG PS ( Conclusion: Euthyroid sick syndrome may be relatively common among patients with HSC and is more frequently observed in those hospitalized for supportive care. In this patient population, ESS was significantly associated with ECOG PS, Hb, and CRP; however, no significant association was identified between ESS and 25(OH)D.