SAT-312 - Inflammatory Biomarkers as Predictors for 90-Day Mortality in Hospitalized Patients with Amiodarone-Induced Thyrotoxicosis - A Historical Cohort Study

Background: Amiodarone-induced thyrotoxicosis (AIT) is associated with high mortality rates, especially in patients with underlying severe cardiac disease. The prognostic value of inflammatory biomarkers for predicting 90-day mortality remains uncertain. This study evaluates their potential utility as predictive markers.

Methods: This historical-prospective cohort study was conducted at a large tertiary medical center and included all consecutive patients aged ≥18 years hospitalized with AIT between January 2015 and December 2023. Data on demographics, clinical characteristics, admission laboratory results, AIT-specific therapy, and 90-day all-cause mortality were collected. Inflammatory biomarkers were calculated using laboratory test results obtained at admission. The discriminative ability of each biomarker was evaluated using a receiver operating characteristic curve, and DeLong’s test was used to compare the areas under the curve (AUCs). A classification and regression tree (CART) model was employed to identify patient subgroups at increased mortality risk. A sensitivity analysis was performed in patients with severe biochemical thyrotoxicosis.

Results: The study included 209 patients (mean age 71 ± 13 years; 42.6% female), of whom 96 (45.9%) died within 90 days. Patients who died exhibited significantly higher inflammatory burden at admission. All inflammatory biomarkers (neutrophil-to-lymphocyte ratio [NLR], C-reactive protein-to-lymphocyte ratio [CLR], and multi-inflammatory index [MII]) were significantly elevated in non-survivors. Among these, CLR demonstrated the highest discriminatory ability for 90-day mortality in the overall cohort (AUC = 0.705), while all three biomarkers showed strong performance in the sensitivity analysis (AUCs 0.709–0.744). CART analysis identified distinct mortality risk groups based on MII and CLR thresholds, with mortality rates ranging from 12% to over 70%. Traditional demographic factors and comorbidities were not independently associated with short-term mortality.

Conclusions: This study identified a significant association between the inflammatory biomarkers CLR, NLR, and MII assessed at hospital admission and 90-day mortality in patients hospitalized with AIT. These biomarkers are readily accessible through routine blood tests, and they may facilitate early risk stratification and inform clinical decisions regarding targeted interventions and close clinical follow-up.

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