Frequency, trends and institutional variation in 30-day all-cause mortality and unplanned readmissions following hospitalisation for heart failure in Australia and New Zealand

Aims: National 30-day mortality and readmission rates after heart failure (HF) hospitalisations are a focus of US policy intervention and yet have rarely been assessed in other comparable countries. We examined the frequency, trends and institutional variation in 30-day mortality and unplanned readmission rates after HF hospitalisations in Australia and New Zealand.

Methods and results: We included patients >18 years hospitalised with HF at all public and most private hospitals from 2010-15. The primary outcomes were the frequencies of 30-day mortality and unplanned readmissions, and the institutional risk-standardised mortality rate (RSMR) and readmission rate (RSRR) evaluated using separate cohorts. The mortality cohort included 153 592 patients (mean age 78.9 ± 11.8 years, 51.5% male) with 16 442 (10.7%) deaths within 30 days. The readmission cohort included 148 704 patients (mean age 78.6 ± 11.9 years, 51.7% male) with 33 158 (22.3%) unplanned readmission within 30 days. In 392 hospitals with at least 25 HF hospitalisations, the median RSMR was 10.7% (range 6.1-17.3%) with 59 hospitals significantly different from the national average. Similarly, in 391 hospitals with at least 25 HF hospitalisations, the median RSRR was 22.3% (range 17.7-27.1%) with 24 hospitals significantly different from the average. From 2010-15, the adjusted 30-day mortality [odds ratio (OR) 0.991/month, 95% confidence interval (CI) 0.990-0.992, P < 0.01] and unplanned readmission (OR 0.998/month, 95% CI 0.998-0.999, P < 0.01) rates declined.

Conclusion: Within 30 days of a HF hospitalisation, one in 10 patients died and almost a quarter of those surviving experienced an unplanned readmission. The risk of these outcomes varied widely among hospitals suggesting disparities in HF care quality. Nevertheless, a substantial decline in 30-day mortality and a modest decline in readmissions occurred over the study period.