Relation of subclinical hypothyroidism to acute kidney injury among st-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention

Background: Data suggest that subclinical hypothyroidism (SCH) is associated with progression of chronic renal disease; however, no study to date has assessed the possible relation between SCH and acute deterioration of renal function. Objectives: To investigate the possible relation between SCH and acute kidney injury (AKI) in a large cohort of patients with ST-elevation myocardial infarction (STEMI) treated with primary coronary intervention (PCI). Methods: We evaluated thyroid stimulating hormone (TSH) and free T4 levels of 1591 STEMI patients with no known history of hypothyroidism or thyroid replacement treatment who were admitted to the coronary care unit (October 2007-August 2017). The presence of SCH was defined as TSH levels ≥ 5 mU/ml in the presence of normal free T4 levels. Patients were assessed for development of AKI (0.3 mg/dl increase in serum creatinine, according to the KDIGO criteria). Results: The presence of SCH was demonstrated in 68/1593 (4.2%) STEMI patients. Patients presenting with SCH had more AKI complications during the course of STEMI (20.6% vs. 9.6%, P = 0.003) and had significantly higher serum creatinine change throughout hospitalization (0.19 mg/dl vs. 0.08 mg/dl, P = 0.04). No significant difference was present in groups regarding baseline renal function and the amount of contrast volume delivered during coronary angiography. In multivariate logistic regression model, SCH was independently associated with AKI (odds ratio = 2.19, 95% confidence interval 1.05-4.54, P = 0.04). Conclusions: Among STEMI patients treated with PCI, the presence of SCH is common and may serve as a significant marker for AKI.