Readmission and death in patients admitted with new-onset versus worsening of chronic heart failure: insights from a nationwide cohort.

<bold>Aims: </bold>To examine the rates of all-cause mortality and heart failure (HF) readmission in patients hospitalized with decompensated HF according to HF duration - new-onset HF and worsening of chronic HF.<bold>Methods and Results: </bold>In this nationwide observational cohort study, 17 176 patients were included at first hospital admission for HF in the period 2013-2015 using data from Danish nationwide registries. In total, 8860 (51.6%) patients were admitted with new-onset HF and 8316 (48.4%) with worsening of chronic HF. Patients with worsening of chronic HF were characterized by a greater comorbidity burden compared with patients with new-onset HF. The rates of outcomes were examined by multivariable Cox regression models, adjusted for age, sex, and comorbidity. Worsening of chronic HF was associated with a higher rate of the composite endpoint of all-cause mortality or HF readmission [hazard ratio (HR) 1.37, 95% confidence interval (CI) 1.31-1.43], all-cause mortality (HR 1.22, 95% CI 1.16-1.28), and HF readmission (HR 1.81, 95% CI 1.69-1.93) compared with new-onset HF. There was an interaction between atrial fibrillation (AF), HF duration, and outcome: in worsening of chronic HF, the rate of the composite endpoint was higher in patients with AF compared with those without (HR 1.12, 95% CI 1.07-1.19), whereas in new-onset HF, the rate of the composite endpoint was lower in patients with AF compared with those without (HR 0.91, 95% CI 0.85-0.96) (P-value for interaction <0.001).<bold>Conclusions: </bold>Among patients hospitalized with decompensated HF, worsening of chronic HF was associated with poorer outcomes compared with new-onset HF. [ABSTRACT FROM AUTHOR]