Estimates of variation (v) in severe ROP rates among 25 ANZNN NICUs (1998-9), based on adjustment for 0, 2, and 3 predictor variables (gestational age (GA), weight for gestational age, sex)
| Predictor variables adjusted for | v | 20th centilerate (%) | Centile gain | Outlier gain | |
|---|---|---|---|---|---|
| Variation is expressed as: (a) v, the standard deviation of the true incidence ratios (O/E) for all study NICUs; (b) 20th centile of the rates of severe ROP adjusted for sampling variability and predictors; (c) “centile gain’” the number of cases that might be prevented in 2 years if the overall rate of severe ROP was reduced to the 20th centile rate; (d) “outlier gain,” the number of cases that might be prevented in 2 years if NICUs with excess rates improved to the average. | |||||
| None | 0.4747 | 6.46 | 67 | 25 | |
| GA, sex | 0.4986 | 6.09 | 75 | 26 | |
| GA, sex, weight for GA | 0.5247 | 5.88 | 79 | 26 | |