Of the 81 610 HF patients, 670 (<1%) patients were less than 18 years old, 15 949 (19.5%) did not have any follow up medical encounter either in the year before or after BNP test was done, and 636 (<1%) had missing information on medical encounter type and hence were excluded from the analysis (Figure S1). This evidence concerns the gene NPPB and hydrops fetalis.