Coincident with the decline in SMRs, declines were observed in total hospital LOS (13.0, 12.4, 11.6, and 11.1 days in years 1, 2, 3, and 4, respectively; p < 0.001) and ICU LOS (4.0, 3.9, 3.8, and 3.8 days in years 1 to 4, respectively; p < 0.001), while the proportion of patients discharged to skilled nursing rehabilitation facilities and nursing homes increased (9.5%, 11.2%, 12.3%, and 15.8%, in years 1 to 4, respectively; p < 0.001). Further analysis indicated that patients discharged to these facilities had higher admission severity of illness than patients discharged to home, as measured by mean APACHE III scores (57.3 vs 38.9; p < 0.001) and predicted risk of death (15.9% vs 5.7%; p < 0.001), suggesting that such patients may have been more likely to die after discharge than patients who were discharged to home.
To examine the potential impact of these changes in discharge triage on mortality performance, a further multivariable model was developed using 102,148 patients that excluded the 14,192 patients discharged to skilled nursing rehabilitation facilities and nursing homes. The ROC curve area of this model was 0.925, and the Hosmer-Lemeshow statistic was not significant (x2 = 9.2, 8 df, p = 0.33). The aggregate in-hospital mortality for this population was 12.9% review inhalers for asthma. Applying risk predictions from this model, overall SMRs remained relatively stable over the 4 years of data collection (1.02, 1.01, 0.98, and 1.00 in years 1, 2, 3, and 4), suggesting that the decline in standardized mortality may have reflected changes in hospital discharge practices. However, variability in hospital SMRs did not decline. For example, hospital SMRs ranged from 0.80 to 1.25; eight hospitals had SMRs that were lower (p < 0.01) than 1.0, and three hospitals had SMRs that were greater (p < 0.01) than 1.0. Moreover, the difference in mean SMRs between major teaching and other hospitals remained (mean SMRs 0.94 ± 0.06 vs 1.06 ± 0.13, respectively; p = .04).