Asthma and allergy trajectories in children based on combined parental report and register data.

Background: Trajectories of asthma and allergy in children are heterogeneous and commonly derived from parental report of disease or clinical records. This study combined parental-reported and register-based dispensed medication data to characterize childhood trajectories of co-existing asthma, allergic rhinitis, and eczema.

Methods: From a Swedish population-based birth cohort (N = 5654), survey responses collected at the age of 1, 4.5, 8, and 12 years were linked to dispensed medication register data for the period of 2-13 years. Trajectories were identified with latent class analysis. Statistical metrics and clinical interpretability guided the model selection.

Results: Nine distinct trajectories were identified: three asthma-dominated (early-onset remitting [n = 189, 3.3%], late-onset [n = 117, 2.1%], and persistent [n = 149, 2.6%]), two eczema-dominated (persistent [n = 190, 3.4%] and remitting [n = 432, 7.6%]), one allergic rhinitis-dominated (late-onset [n = 259, 4.6%]), two multimorbidity (mid-childhood asthma and late-onset allergic rhinitis [n = 144, 2.5%], and persistent eczema and late-onset allergic rhinitis [n = 90, 1.6%]), and one low-disease burden trajectory (n = 4084, 72.2%). Differences were seen across the trajectories in the proportion of parental report of disease and dispensed medication as well as by class and quantity of medication dispensed.

Conclusion: Combined parental-reported and dispensed medication data enriches characterization of longitudinal trajectories of asthma and allergy in children by merging subjective experience of disease with healthcare utilization. The identified trajectories were characterized by distinct disease development and prescription patterns suggesting clinically differential morbidity burden.