Objective: Determine patient and hospital-level variation in proportions of low-severity admissions.
Design: Retrospective cohort study.
Setting: Thirty hospitals in a large metropolitan region.
Patients: A total of 43,209 consecutive eligible patients discharged in 1991 through 1993 with congestive heart failure (n = 25,213) or pneumonia (n = 17,995).
Measurements and main results: Admission severity of illness was measured from validated multivariable models that estimated the risk of in-hospital death; models were based on clinical data abstracted from patients' medical records. Admissions were categorized as "low severity" if the predicted risk of death was less than 1%. Nearly 15% of patients (n = 6,382) were categorized as low-severity admissions. Compared with other patients, low-severity admissions were more likely (p < .001) to be nonwhite and to have Medicaid or be uninsured. Low-severity admissions had shorter median length of stay (4 vs 7 days; p < .001), but accounted for 10% of the total number of hospital days. For congestive heart failure, proportions of low-severity admissions across hospitals ranged from 10% to 25%; 12 hospitals had rates that were significantly different (p < .01) than the overall rate of 17%. For pneumonia, proportions ranged from 3% to 22%; 12 hospitals had rates different from the overall rate of 12%. Variation across hospitals remained after adjusting for patient sociodemographic factors.
Conclusions: Rates of low-severity admissions for congestive heart failure and pneumonia varied across hospitals and were higher among nonwhite and poorly insured patients. Although the current study does not identify causes of this variability, possible explanations include differences in access to ambulatory services, decisions to admit patients for clinical indications unrelated to the risk of hospital mortality, and variability in admission practices of individual physicians and hospitals. The development of protocols for ambulatory management of low-severity patients and improvement of access to outpatient care would most likely decrease the utilization of more costly hospital services.