Table 4.

Negative Binomial Regression Results for PICU Length of Stay

VariableRegression CoefficientStandard ErrorProbabilityAdjusted IRR (95% CI)
Volume−.0002.0001.030.980 (.975–.985)
PRISM.106.007<.0011.58 (1.55–1.62)
PRISM2 −.002.0002<.001
Patient age (mo)−.001.0002<.001.99 (.98–.99)
Trauma patient.145.063.0221.16 (1.02–1.31)
Endocrine disease−.447.062<.001.64 (.57–.72)
Oncologic disease.291.064<.0011.34 (1.04–1.52)
Circulatory disease.258.048<.0011.29 (1.18–1.42)
Congenital anomaly.140.035<.0011.15 (1.07–1.23)
Ill-defined condition.234.041<.0011.26 (1.17–1.37)
Infection.185.070.0081.20 (1.05–1.38)
Respiratory condition.154.050.0021.17 (1.06–1.29)
Nervous system disease.088.038.0221.09 (1.01–1.18)
Constant.891.104<.001
  • * IRR based on change in volume of 100 patients.

  • IRR based on a PRISM score of 20 compared with a score of 10.

  • IRR based on change in patient age of 12 months.