(HealthDay)—Hospital quality contributes to readmission rates independent of factors involving patients, according to a study published in the Sept. 14 issue of the New England Journal of Medicine.

Harlan M. Krumholz, M.D., from the Yale-New Haven Hospital in Connecticut, and colleagues divided the Centers for Medicare & Medicaid Services hospital-wide measure cohort into two random samples. The first was used to calculate the risk-standardized readmission rate within 30 days for each hospital, with hospitals classified into performance quartiles. The study sample identified from the second sample included patients with two admissions for similar diagnoses at different hospitals. Readmission rates were compared among patients who had been admitted to hospitals in different performance quartiles.

The researchers found that the median risk-standardized readmission rate was 15.5 percent in the performance-classification sample. In the study sample (37,508 patients with two admissions for similar diagnoses at 4,272 different hospitals), the observed readmission rate was higher for patients admitted to hospitals in a worse-performing versus a better-performing quartile. The only significant difference was seen when patients were admitted to hospitals in which one was in the best-performing and one in the worst-performing quartile (absolute difference in readmission rate, 2.0 percentage points).

"The findings suggest that quality contributes in part to independent of factors involving ," the authors write.