Hospitalization for heart failure (HHF) is associated with poor postdischarge outcomes but the role of time since most recent HHF and potential treatment interactions are unknown. We aimed to assess history of and time since previous HHF, associations with composite of cardiovascular (CV) death and total HHF, first HHF and interactions with randomization to spironolactone, in heart failure with preserved ejection fraction.

We assessed these objectives using uni- and multivariable regressions and spline analyses in TOPCAT-Americas. Among 1,765 patients, 66% had a previous HHF. Over a median of 2.9 years, 1,064 composite events of CV death or total HHFs occurred. Previous HHF was associated with more severe HF, and was independently associated with the composite outcome (HR 1.26, 95%CI 1.05-1.52, P = .014), and all secondary outcomes. A shorter time since most recent HHF appeared to be associated with subsequent first HHF, but not the composite of CV death or total HHF.

Spironolactone had a significant interaction with previous HHF (interaction-P .046). Patients without a previous HHF had a larger effect of spironolactone on the composite outcome (HR 0.63, 95%CI 0.46-0.87, P = .005) than patients with a previous HHF (HR 0.91, 95%CI 0.78-1.06, P = .224).

In TOPCAT-Americas, previous HHF was associated with CV death and first and total HHF. Duration since most recent HHF seemed to be associated with time to first HHF only. Spironolactone was associated with better outcomes in patients without a previous HHF. This interaction is hypothesis-generating and requires validation in future trials.