Model of prediction of outcome according to count of four risk factors (bronchopulmonary dysplasia, major brain injury, retinopathy of prematurity stage 3 or higher, and necrotizing enterocolitis and/or proven sepsis). The proportion of adverse outcome (A) and of favourable outcome (B) with 95%-confidence intervals and the number of infants per group are shown. The dotted horizontal line indicates the average proportion of the respective outcome. The dashed diagonal line represents the regression line. ND, neurodevelopmental disability. The figure shows data from 670 children because information on risk factor ROP (stage 3 or higher) was not available in 14 of 684 patients.