The objectives of the current study were (i) to compare the clinical and paraclinical features between patients with advanced HF and those with mild HF (by NYHA classification); (ii) to compare the distributions of NT-proBNP, FGF21, Galectin-3 and Copeptin between the studied groups; (iii) to assess the performance of NT-proBNP, FGF21, Galectin-3 and Copeptin to discriminate between advanced and mild HF; and (iv) to evaluate the potential correlations between the studied biomarkers, echocardiographic and clinical parameters in T2DM patients stratified by the severity of HF. The gene discussed is FGF21; the disease is hydrops fetalis.