APPLICATION OF THE NON-PROPORTIONAL RATES MODEL TO RECURRENT EVENT DATA: ANALYSIS OF RISK FACTORS FOR PRE-SCHOOL ASTHMA - Quantitative Medical Data Analysis Using Mathematical Tools and Statistical Techniques - page 197

Unexposed children Exposed children

0 1 2 3 4 0 1 2 3 4

t (years) t (years)

Unexposed children Exposed children

0 1 2 3 4 0 1 2 3 4

t (years) t (years)

Fig. 5. Fitted (solid lines) versus observed (dots) number of asthma-attributable hospi-
talizations (top two panels) and days hospitalized (bottom panels) among \unexposed"
(i.e., LBW i +: : :+T T N i = 0) (left panels) and \exposed" (i.e., LBW i +: : :+T T N i > 0)
children (right panels) for t2(0; 5] yrs.

of hospitalizations and mean days hospitalized. The increase associated with
male gender was found to decrease steadily and monotonically during the
0 to 4 age interval.
We then tted semi-parametric marginal rates models with time-
dependent covariates to data from a retrospective birth cohort study.
Among all simulation trials, the last of line of Table 1 is most relevant in