The Chinese adverse prognosis of very preterm infants (CARE-Preterm) cohort: study design and baseline characteristics for a prospective multicenter cohort study.

Background: As the increasing survival of preterm infants bearing lower gestational age (GA) and birth weight (BW), new challenges have emerged regarding their management and prognosis. In low- and middle-income countries, there is notable absence of prospective multicenter cohorts to accurately reflect their real treatment capacity for these preterm infants. This cohort study aims to fill this gap by investigating the impact of perinatal management on the prognosis of preterm infants in Northern China.

Methods: The Chinese Adverse Prognosis of Very Preterm infants (CARE-Preterm) cohort study is a prospective, multicenter, longitudinal, and open cohort study based on the Sino-northern Neonatal Network (SNN) since 2018, covering 60 neonatal intensive care units from 8 densely-populated provinces and autonomous regions in Northern China. All very preterm infants (VPIs) born with GA < 32 weeks or very low birth weight infants (VLBWI) born with BW < 1500 g admitted alive to the participating units are continuously enrolled from January 1, 2018. Baseline clinical data and biological samples are longitudinally collected from the perinatal period to discharge.

Results: From January 1, 2018, to December 31, 2022, approximately 10,447 infants were included and 9325 infants were discharged alive. Notably,1472 (14.09%) were born with GA < 28 weeks, and 1566 (14.99%) with BW < 1000 g. Among the 9325 survivors, the smallest GA and BW were 23^+ 3 weeks and 450 g, respectively. The main findings of this cohort study highlight substantial improvements in perinatal medicine treatment capabilities and current treatment bottlenecks.

Conclusion: This cohort study provides crucial insight into updated real-world data from low- and middle-income countries, helping to identify treatment bottlenecks and improve both the survival rate and life quality for preterm infants. Furthermore, it is expected to serve as a reference for establishing population-based cohort studies in other low and middle-income countries.

Trial registration: The current projects based on this cohort study have been registered in the Chinese Clinical Trial Registration Center (Registration number: ChiCTR1900025234, ChiCTR1900020861, ChiCTR2000037918, ChiCTR2000029162, ChiCTR2100053780 and ChiCTR2200066764).