Irisin levels in patients with severe hypothyroidism may be a potential biomarker for predicting myocardial injury. This cross-sectional study finding was published in the International Journal of Endocrinology.
Study participants (n=25) with newly diagnosed, untreated, severe primary hypothyroidism and a group of age- and gender-matched healthy controls (n=17) were recruited between 2014 and 2015 at the Beijing Chaoyang Hospital in China.
Researchers assessed participants using anthropometric indicators, medial history, and biochemical tests. Blood samples were collected after an overnight fast.
The hypothyroid and control cohorts were aged mean 37.40±1.92 and 33.41±1.96 years and BMI was 25.74±0.70 and 22.25±0.86 kg/m2, respectively. The hypothyroidism group differed significantly from the control group for triglycerides (P = 001), total cholesterol (P = 001), creatine kinase (P = 001), free triiodothyroinine (P = 001), free throxine (P = 001), thyroid stimulating hormone (P = 001), BMI (P =.003), low-density lipoprotein cholesterol (P =.004), and irisin (P =.014).
During cardiac assessment, 10 patients in the hypothyroidism cohort had pericardial effusions and the hypothyroidism group as a whole exhibited reduced peak filling rates (P <.05) and increased myocardial T1 (P <.01). These observations indicated diastolic dysfunction and the presence of early diffuse myocardial lesions.
Among the subgroup of patients with severe hypothyroidism who had pericardial effusion, irisin levels were lower than those without pericardial effusion (mean, 13.16±3.93 vs 51.85±6.38 ng/mL; P <.01), respectively.
Serum irisin had a diagnostic sensitivity for pericardial effusion of 73.3% and specificity of 100.0%, with an area under the curve (AUC) of 0.920 (P <.001). The cutoff value of serum irisin for diagnosing pericardial effusion in people with severe hypothyroidism was 36.94 ng/mL.
Circulating irisin concentrations were found to be negatively correlated with left ventricular T1 value levels (r, -0.494; P <.05) and native T1 values (b, 1.568; P <.05). After adjusting for potential confounders, native T1 levels remained significantly associated among patients with severe hypothyroidism (b, -1.473; P <.05).
This study was cross-sectional with a small sample size and could not demonstrate causality, the investigators acknowledged. They also noted exercise is considered a primary inducement of irisin secretion and its potential influence on results could not be eliminated.
“Low serum irisin levels may indicate diffuse myocardial injuries for patients with severe hypothyroidism,” the study authors said, acknowledging that a larger sample size and multicenter studies are needed to confirm this correlation.
Yao Z, Ding X, Gao X, et al. Irisin as a Potential Biomarker Associated with Myocardial Injuries in Patients with Severe Hypothyroidism. Int J Endocrinol. 2021;2021:3116068. doi:10.1155/2021/3116068