Background: Rising NT-proBNP are associated with reduced survival patients with HFrEF. However, it remains to be conclusively and formally demonstrated that the temporal trend in NT-proBNP level carries prognostic significance in HFpEF. Objective: To determine whether there is an association between rising NT-proBNP levels and 6-month survival in patients with HFpEF and HFrEF. Methods: We examined a cohort of 5203 patients to 5 hospitals in a regional health care system — who had at least one admission to the hospital with diagnoses of heart failure over a 3-year period. Kaplan-Meier survival curves were constructed for patients with downtrending (>25% net decrease), stable or uptrending (>25% net increase) NT-proBNP levels in HF, HFpEF and HFrEF patients. The log-rank test was used to test for differences in 6-month survival amongst the groups. Multivariate extended Cox regression models were constructed for 6-month survival with NT-proBNP as a time-varying covariate. Age, albumin, sex, race, serum creatinine, systolic and diastolic blood pressures and Charlson comorbidity scores at baseline were used as covariates in the model. Separate analyses were done for HFpEF and HFrEF patients. Results: HFpEF and HFrEF patients with up-trending levels had significantly lower 6-month survival rates than patients with downtrending or stable NT-proBNP levels. A doubling of the NT-proBNP level in patients was significantly associated with reduced 6-month survival in patients with in both subgroups of HF, HFpEF and HFrEF (HFpEF-HR: 1.53(1.49-2.57), HFrEF HR: 1.45(1.43-1.48) after adjusting for covariates.