Incident heart failure hospitalization and subsequent mortality in chronic heart failure: a propensity-matched study

Abstract

Objective: Hospitalization for worsening heart failure (HF) is common and associated with high mortality. However, the effect of incident HF hospitalization (compared with no HF hospitalization) on subsequent mortality has not been studied in a propensity-matched population of chronic HF patients.

Methods: In the Digitalis Investigation Group trial, 5501 patients had no HF hospitalizations (4512 alive at 2 years after randomization) and 1732 patients had HF hospitalizations during the first 2 years (1091 alive at 2 years). Propensity scores for incident HF hospitalization during the first 2 years after randomization were calculated for each patient and used to match 1057 patients (97%) who had 2-year HF hospitalization with 1057 patients who had no HF hospitalization. We used matched Cox regression analysis to estimate the effect of incident HF hospitalization during the first 2 years after randomization on post-2-year mortality.

Results: Compared with 153 deaths (rate, 420/10,000 person-years) in the no HF hospitalization group, 334 deaths (rate, 964/10,000 person-years) occurred in the HF hospitalization group (hazard ratio 2.49; 95% confidence interval 1.97-3.13; P < .0001). The hazard ratios (95% confidence intervals) for cardiovascular and HF mortality were 2.88 (2.23-3.74; P < .0001) and 5.22 (3.34-8.15; P < .0001), respectively.

Conclusions: Hospitalization for worsening HF was associated with increased risk of subsequent mortality in ambulatory patients with chronic HF. These results highlight the importance of HF hospitalization as a marker of disease progression and poor outcomes in chronic HF, reinforcing the need for prevention of HF hospitalizations and strategies to improve postdischarge outcomes.

Figure 1

Flow chart for the assembly of matched cohort

Figure 2

Absolute standardized differences of baseline covariates between patients with and without hospitalization for heart failure, before and after propensity score matching

Figure 3

Kaplan-Meier plots for cumulative risk of death due to (a) all causes, (b) cardiovascular causes, and (c) progressive heart failure (HF). HFH, heart failure hospitalization; HR, hazard ratio; CI, confidence interval.

Figure 4

Hazard ratios (HR) and 95% confidence intervals (CI) for post two-year all-cause mortality when heart failure hospitalization (HFH) during the first two years was compared with no HFH in subgroups of patients with chronic heart failure (ACE, angiotensin-converting enzyme; HFH, heart failure hospitalization; NYHA, New York Heart Association)