Purpose: The purpose of the study was to explore the predictive value of free triiodothyronine to free thyroxine ratio (FT3/FT4) on contrast-associated acute kidney injury (CA-AKI) and poor prognosis in euthyroid patients after percutaneous coronary intervention (PCI).
Methods: The present study included 3,116 euthyroid patients who underwent elective PCI. The main outcome was CA-AKI, and the secondary outcome was long-term mortality. All patients were divided into three groups according to the tertiles of FT3/FT4 levels.
Results: During hospitalization, a total of 160 cases (5.1%) of CA-AKI occurred. Restricted cubic spline (RCS) analysis indicated a linear and negative relationship between FT3/FT4 and CA-AKI risk (P for nonlinearity = 0.2621). Besides, the fully-adjusted logistic regression model revealed that patients in tertile 3 (low FT3/FT4 group) had 1.82 times [odds ratio (OR): 1.82, 95% confidence interval (CI): 1.13-3.02, P = 0.016] as high as the risk of CA-AKI than those in tertile 1 (high FT3/FT4 group). Similarly, patients in tertile 3 were observed to have a higher incidence of long-term mortality [fully-adjusted hazard ratio (HR): 1.58, 95% CI: 1.07-2.32, P = 0.021]. Similarly, the Kaplan-Meier curves displayed significant differences in long-term mortality among the three groups (log-rank test, P < 0.001).
Conclusion: In euthyroid patients undergoing elective PCI, low levels of FT3/FT4 were independently associated with an increased risk of CA-AKI and long-term mortality. Routine evaluation of FT3/FT4 may aid in risk stratification and guide treatment decisions within this particular patient group.
Keywords: Contrast-associated acute kidney injury; Free triiodothyronine to free thyroxine ratio; Mortality; Percutaneous coronary intervention.
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