Preterm birth and risk of hospitalisation for complex chronic conditions during childhood and adolescence

Aim: To examine the relationship between preterm birth and hospitalisation for paediatric complex chronic conditions. Methods: We conducted a cohort study of 1 269 745 children born between 2006 and 2022 in Quebec, Canada. We classified preterm birth as extreme (<28 weeks), very (28-31 weeks), and moderate (32-36 weeks). The outcome was hospitalisation for complex chronic conditions, including neurologic, neuromuscular, cardiovascular, respiratory, renal, gastrointestinal, haematologic, immunologic, endocrine, and neoplastic disorders up to 16 years of age. We computed adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the association between preterm birth and complex chronic conditions during 9 948 734 person-years of follow-up. Results: Hospitalisation rates for complex chronic conditions were higher for children born preterm than at term (6.88 vs. 2.24 per 1000 person-years). Preterm birth was associated with all complex chronic conditions, especially respiratory (HR 4.64, 95% CI 4.01-5.37), cardiovascular (HR 3.68, 95% CI 3.47-3.90), and neurologic disorders (HR 3.48, 95% CI 3.21-3.77). Associations were present at all ages and for all degrees of prematurity, but were strongest with extreme prematurity. Conclusion: Preterm birth increases the risk of hospitalisation for complex chronic conditions up to age 16 years. Preterm children may benefit from enhanced care throughout childhood and adolescence.