When the biomarker combination was defined according to the previously defined cut-off points [4], the frequency of patients exhibiting the combination of high PICP (≥111 ng/mL) and low CITP:MMP-1 ratio (≤1.97) was higher (p < 0.001) in the HFpEF group (10.5%) as compared with the non-HF group (0.4%). The gene discussed is MMP1; the disease is hydrops fetalis.