In the previous Kosiborod et al. study, oedema was reported more frequently with SZC 15 g than other doses or placebo; however, more patients in this dose group had HF, an estimated glomerular filtration rate <60 mL/min/1.73 m2, or high levels of brain natriuretic peptide at baseline.15 Because SZC contains sodium, whether these SMQ oedema events were related to some degree of sodium retention is unknown. Here, NPPB is linked to hydrops fetalis.