BACKGROUND: Circulating microRNAs (miRNAs) are emerging as novel biomarkers for detecting cardiovascular diseases. Here, circulating miR-133a and miR-221 were investigated as potential diagnostic biomarkers for heart failure (HF) patients, particularly in elderly patients.

MATERIAL AND METHODS: A total of 94 elderly HF patients (mean age=77.4 years old) and 31 healthy controls (age- and sex-matched) participated in this study. Plasma NT-proBNP levels were measured using an electrochemiluminescence immunoassay, and circulating miR-133a and miR-221 levels were examined using real-time quantitative PCR, with diagnostic efficacies determined for each independently and in combination.

RESULTS: MiR-133a expression increased by 4.6-fold (P<0.001) and miR-221 expression increased by 2.0-fold (P<0.001) in the elderly HF patients relative to the healthy controls. ROC curves were generated and AUC values of 0.863 for miR-133a (CI95%: 0.800–0.927), 0.718 for miR-221 (CI95%: 0.622–0.813), and 0.895 for NT-proBNP (CI95%: 0.841–0.948) were obtained. Unlike NT-proBNP, miR-133a and miR-221 were found to be unaffected by age, BMI, renal function, albumin, or Hb levels. More importantly, the diagnostic value of NT-proBNP was found to be improved when combined with any of the examined miRNA biomarkers alone or in a panel. When combining miR-133a with NT-proBNP, an AUC value of 0.975 (CI95%: 0.950–0.999) was obtained, which was significantly higher than for NT-proBNP alone (z=2.395, P=0.016).

CONCLUSIONS: miR-133a and miR-221 can serve as potential HF diagnostic biomarkers in elderly patients. Moreover, the diagnostic accuracy of NT-proBNP can be improved by the addition of miR-133a.

Keywords: Biological Markers