Euthyroid sick syndrome in hip fractures: Valuation of vitamin D and parathyroid hormone axis

Abstract

Introduction: Femur fracture is an acute event with a high incidence and mortality worldwide. Euthyroid sick syndrome (ESS) is a disease characterized by an alteration of fT3 in the absence of a primary thyroid pathology. The aim of the study is evaluating the association between femur fracture and ESS and post-operative fluctuations of the parathyroid hormone (PTH) and vitamin D and their physio-pathological implications.

Materials and methods: All patients older than 65 years, admitted in our emergency care unit with a diagnosis of proximal femur fracture were recruited. Exclusion criteria were acute cardio-pulmonary events, neoplastic diseases, any thyroid or endocrine pathology and use of drugs with thyroidal interactions. All patients underwent surgery within 48 h from the injury. The outcome of the study is the presence of ESS, moreover, post-operative fluctuations of the PTH and vitamin D are also evaluated.

Result: 45 patients (13 men and 32 females) were enrolled. 20 patients had a normal thyroidal function, while 23 had a diagnosis of ESS. Mean age was 81.9. BMI was lower in the ESS group than the controls (25,3 vs 22,7; p < 0.02). In the ESS group a significantly higher decrease in Vitamin D levels was observed, compared to controls (3.96 ng/ml, p<0.001). Values of PTH were significantly different between the two groups, with a level 44.29 pg/ml lower among the ESS group compared to controls (p = 0.002). In the ESS group a significant decrease of serum calcium on the first post-surgery day was observed, compared to controls (8,7 vs 8,3; p < 0,01). There were no differences in the CCI, serum electrolytes and other variables collected between the two groups.

Conclusion: Part of the geriatric population suffering from fractures of the proximal femur are affected by ESS. This population displays anomalies of the Vitamin d-PTH axis and a lower BMI.

Keywords: Calcium metabolism; Euthyroid sick syndrome; Hip fractures; Non thyroidal illness syndrome; Parathyroid hormone; Vitamin D.