NT-proBNP is a marker of both left and right heart disease and is released by cardiac myocytes in response to increased wall stress.[14–16] Elevated NT-proBNP levels have been associated with worse outcomes, including mortality, in populations with congestive heart failure (CHF), pulmonary hypertension, sickle cell disease, and COPD.[17–22] Prior work has shown that brain natriuretic peptide is elevated in HIV-infected persons with right and left heart dysfunction.[23–26] Elevated NT-proBNP was also associated with increased risk for cardiovascular events in HIV-infected persons[27]. Here, NPPB is linked to sickle cell disease.