Population analysis of temporal trends and between-hospital variation in mortality, readmission and prolonged length-of-stay between 2008 and 2018: improving integrated care by knowledge sharing of hospitals’ care progress

Background: Despite the benefits of studying multiple patient outcomes together, research on between-hospital variation has often focused on single outcomes or disease-specific study populations. In the study we would like to present, we examined nationwide temporal trends and between-hospital variation in three important patient outcomes: (1) in-hospital mortality as a pinnacle measure of patient safety; (2) 30-day readmissions as an accountability measure for hospitals; and (3) prolonged length-of-stay, i.e. a length-of-stay above the All-Patient-Refined Diagnoses-Related-Group (APR-DRG)-specific 90th percentile (pLOS) because of its correlations with complications and costs of care. Who is it for: This study is highly relevant for both clinicians and policymakers on hospital and governmental level. Methods: In this observational study, we made use of a large administrative dataset that is today primarily used for financial purposes (Minimum Hospital Data). We modelled 13,660,187 admissions between 2008 and 2018 in 90 (89%) Belgian acute-care hospitals using APR-DRG-specific logistic regression. We studied temporal trends in outcomes, hospital-level associations between outcomes, associations of outcomes with hospitals characteristics, and evaluated how many and which APR-DRGs explained between-hospital variation. Findings: Between 2008 and 2018, average standardised mortality decreased from 3.4% to 3.1% and pLOS from 10.6% to 8.1%, with significant decreases observed for 181 (out of 243) and 216 (out of 247) APR-DRGs respectively. Readmissions, however, increased from 4.8% to 5.2%. Pearson correlations between rates in 2008 and 2018 were 0.53, 0.49, and 0.74 for mortality, readmission, and pLOS, respectively. Apart from the positive correlation between mortality and pLOS (ρ=0.46), no associations between outcomes were observed in 2018. For many APR-DRGs, the odds of mortality and pLOS were higher in Brussels and Wallonia than in Flanders and higher for general than for academic hospitals, whereas the opposite ...