However, a similar finding has been reported in coronavirus disease 2019 patients.17 Urea is elevated in patients with decreased glomerular filtration rate (suggestive of kidney failure), congestive heart failure, and dehydration.18 In our study, BNP (a marker of heart failure) was also significantly higher in patients who developed NOAF; therefore, urea and BNP may have been elevated together in patients with heart failure. Here, NPPB is linked to heart failure.