Predicting the long-term prognosis of children with symptoms suggestive of asthma at preschool age

Predicted risk of asthma development at 7 to 8 years of age by prediction score.

Predicted and observed risk of asthma development at 7 to 8 years of age per prediction score category. The number of children observed per category is shown in brackets. Expected risk is estimated by using the average score per 5-point category. ∗Estimate for the merged category (≥35 points) is weighed by the number of children actually observed at each 5-point subcategory between 35 and 55 points.

Receiver operating characteristic curve of categorized prediction score on the outcome of asthma at 7 to 8 years of age. Cutoff values of prediction scores are reported in the curve (dots). The area under the receiver operating characteristic curve (C-index) for the categorized score is 0.736 (before validation). Also, the sensitivity and specificity for a doctor's diagnosis of asthma at the age when symptoms were first reported (between 0 and 4 years) are displayed (square).

Proportion of children with asthma at 7 to 8 years of age explained by the proportion of children at highest risk according to the prediction score. Cutoff values of prediction scores are reported in the curve (dots). Also, data for a doctor's diagnosis of asthma at the age when symptoms were first reported (between 0-4 years) are displayed (square).

The PIAMA birth cohort recruitment scheme.

Flowchart of the study population. ∗Two thousand seven hundred seventy-nine allergic and 5,083 nonallergic mothers were invited, as determined before initiation of the study based on a power calculation. Of the 4,146 women included in the study, the proportion of allergic women (31%) was very similar to that in the general Dutch population. †Symptoms were defined as a positive response to the following questions: “Has your child had wheezing or whistling in the chest in the last 12 months?,” “Has your child had cough during the night, when he/she did not have a cold or a chest infection, in the last 12 months?,” or both. Reasons for loss to follow-up included lack of motivation, illness of child, repeated nonresponse, moved, and personal reasons.