Background: Hospital volume is frequently used as a structural metric for assessing quality of care, but its utility in patients admitted with acute heart failure (HF) is not well characterized. Accordingly, we sought to determine the relationship between admission volume, process-of-care metrics, and short- and long-term outcomes in patients admitted with acute HF.
Methods: Patients enrolled in the Get With The Guidelines-HF registry with linked Medicare inpatient data at 342 hospitals were assessed. Volume was assessed both as a continuous variable, and quartiles based on the admitting hospital annual HF case volume, as well: 5 to 38 (quartile 1), 39 to 77 (quartile 2), 78 to 122 (quartile 3), 123 to 457 (quartile 4). The main outcome measures were (1) process measures at discharge (achievement of HF achievement, quality, reporting, and composite metrics); (2) 30-day mortality and hospital readmission; and (3) 6-month mortality and hospital readmission. Adjusted logistic and Cox proportional hazards models were used to study these associations with hospital volume.
Results: A total of 125 595 patients with HF were included. Patients admitted to high-volume hospitals had a higher burden of comorbidities. On multivariable modeling, lower-volume hospitals were significantly less likely to be adherent to HF process measures than higher-volume hospitals. Higher hospital volume was not associated with a difference in in-hospital (odds ratio, 0.99; 95% confidence interval [CI], 0.94-1.05; P=0.78) or 30-day mortality (hazard ratio, 0.99; 95% CI, 0.97-1.01; P=0.26), or 30-day readmissions (hazard ratio, 0.99; 95% CI, 0.97-1.00; P=0.10). There was a weak association of higher volumes with lower 6-month mortality (hazard ratio, 0.98; 95% CI, 0.97-0.99; P=0.001) and lower 6-month all-cause readmissions (hazard ratio, 0.98; 95%, CI 0.97-1.00; P=0.025).
Conclusions: Our analysis of a large contemporary prospective national quality improvement registry of older patients with HF indicates that hospital volume as a structural metric correlates with process measures, but not with 30-day outcomes, and only marginally with outcomes up to 6 months of follow-up. Hospital profiling should focus on participation in systems of care, adherence to process metrics, and risk-standardized outcomes rather than on hospital volume itself.
Keywords: heart failure; hospitals, high volume; hospitals, low volume; mortality; patient readmission; quality of health care.
© 2018 American Heart Association, Inc.