NPPB and bronchopulmonary dysplasia: Preterm infants with the above complications had significantly higher NT-proBNP levels compared to the reference group (BPD: n = 26, median: 1186 ng/l, IQR: 813–2634 ng/l, p < 0.001; BPD-related PH: n = 13, median: 1686, IQR: 823–3117, p < 0.001; late infection: n = 17, median: 805, IQR: 538–1462, p < 0.001; intestinal complications: n = 8, median: 1953, IQR: 959–3368, p < 0.001; IVH: n = 7, median: 2,446, IQR: 1089–3335, p < 0.001 vs. comparison group: n = 26, median: 463, IQR: 364–704).