Preterm Birth and Risk of Health Service Use, Morbidity, and Medication Needs at 5 Years.

Importance: Neonatal intensive care has advanced over recent decades, yet premature birth remains associated with increased neonatal mortality and morbidity. Objective: To describe health service use, morbidity, and medication needs up to age 5 years in a contemporary cohort of children born preterm. Design, Setting, and Participants: This population-based cohort study was conducted in British Columbia (BC), Canada, using health service and pharmacy data linked using provincial administrative databases. Data for a sample of 465 338 children born at 22 to 44 weeks' gestational age (GA) in BC from April 2004 to December 2014 were available. After exclusions for missing information on GA or birth weight, incomplete linkage, or loss of registration, the cohort included 448 819 children (96.5%), with 420 309 (93.6%) having complete 5-year follow-up until 2019. Data were analyzed from May 2023 to April 2025. Exposures: GA at birth, grouped into 8 categories: 22 to 24, 25 to 27, 28 to 30, 31 to 33, 34 to 36, 37 to 38, 39 to 41 weeks (reference), and 42 to 44 weeks. Main Outcomes and Measures: Health service use (hospitalizations and outpatient visits), morbidity (combined inpatient and outpatient diagnoses), and medication needs (outpatient prescriptions). Results: Of 448 819 children (mean [SD] age at follow-up, 4.8 [0.69]; 230 351 [51.3%] male), 42 080 (9.4%) were born before 37 weeks. Hospitalization rates within 5 years were higher for children born earlier compared to 39 to 41 weeks: 22 to 24 weeks (risk ratio [RR], 6.37; 95% CI, 5.62-7.22; risk difference [RD], 464.35 per 1000 patients; 95% CI, 395.62-533.08), 25 to 27 weeks (RR, 4.52; 95% CI, 4.15-4.92; RD, 304.21; 95% CI, 271.42-336.99), 28 to 30 weeks (RR, 2.70; 95% CI, 2.49-2.93; RD, 146.9; 95% CI, 128.01-165.78), 31 to 33 weeks (RR, 1.91; 95% CI, 1.81-2.03; RD, 79.08; 95% CI, 69.56-88.61), 34 to 36 weeks (RR, 1.53; 95% CI, 1.49-1.58; RD, 46.03; 95% CI, 42.13-49.92), and 37-38 weeks (RR, 1.16; 95% CI, 1.14-1.18; RD, 13.84; 95% CI, 11.9-15.78). Earlier GA was associated with increased outpatient visits by age 5 years. Children born preterm exhibited higher rates of respiratory (RR, 1.33; 95% CI, 1.30-1.37 to RR, 3.96; 95% CI, 3.30-4.70), endocrine (RR, 1.13; 95% CI, 1.09-1.18 to RR, 2.37; 95% CI, 1.65-3.27), gastrointestinal (RR, 1.26; 95% CI, 1.11-1.43 to RR, 6.36; 95% CI, 3.05-11.49), kidney (RR, 1.17; 95% CI, 1.08-1.26 to RR, 3.39; 95% CI, 1.86-5.59), neurodevelopmental (RR, 1.60; 95% CI, 1.55-1.66 to RR, 8.04; 95% CI, 6.78-9.44), and sleep (RR, 1.35; 95% CI, 1.21-1.51 to RR, 3.39; 95% CI, 1.34-6.87) disorders. Children born preterm were more likely to receive outpatient antibiotics, bronchodilators, corticosteroids, diuretics, and thyroid hormones. Conclusions and Relevance: In this population-based cohort study, despite neonatal care advancements, children born preterm required more health care resources and faced greater health challenges in their first 5 years.