Factors associated with non-participation of preterm infants at two and five years in a large population-based French healthcare network

Although recommended for the early identification and intervention for developmental impairments, monitoring of preterm infants over several years is hampered by loss of follow-up that inevitably occurs. This study aimed to assess the non-participation of preterm infants in their two- and five-year visits as well as associated factors. Infants born before 33 weeks of gestational age, who were enrolled between 2016 and 2022 in a prospective, population-based cohort in Paris area, France, and were eligible for their two- and five-year visits were selected. Among factors reflecting parental socio-economic characteristics, medical characteristics of the mother and her pregnancy, perinatal characteristics of the child, and contextual variables, those associated with the likelihood of non-participation in the two- or five-year visit were investigated using univariate and multivariable logistic regression models and multiple imputations. Of the 12,685 and 6,661 preterm infants followed-up at two- and five-years, respectively, 4,871 (38.4%) and 4,069 (61.1%) did not participate in the two- and five-year visits. Factors associated with non-participation in the two-year visit were more recent year of birth, younger maternal age, several children at home, lower educational level, mother unemployed or on parental leave, father with an intermediate occupation, tobacco during pregnancy, appropriate or large birth weight for gestational age, and birth in maternity unit other than inclusion. Conversely, factors associated with participation in the two-year visit were a pregnancy achieved by assisted reproductive technology, lower gestational age, postnatal corticosteroid prescription, administration of monoclonal antibodies against respiratory syncytial virus, a bronchopulmonary dysplasia, breastfeeding at discharge, a private or nonhospital referring physician, and living more than 10 km from the referring physician. Factors associated with non-participation in the five-year visit were almost identical. Factors associated with non-participation of preterm infants within a healthcare network were found to be multidimensional. These findings are critical for the development of more intensive and individualized follow-up strategies for preterm infants. The SEV-IDF program is registered with the French data protection authority for clinical research (CNIL, No.1003270/1802983/1802601/1800966/1800657).