NPPB and heart failure: Increasing age is known to cause elevated BNP and NT pro-BNP levels, although the mechanisms remain under investigation.(100,101) Women generally have higher levels of BNP and NT pro-BNP due to higher estrogen levels.(101) Cutoffs based on age and sex have been suggested in primary care patients and heart failure populations but have not been validated in sepsis populations at the current time.(102)