Gestational age and hospital admissions during childhood, the TIGAR study: a population-based, record linkage study in England

Objectives:\r\nTo explore the association between gestation at birth and hospital admissions to age 10 years and how admission rates change throughout childhood. \r\n\r\nDesign:\r\nWe used a population-based record-linkage cohort study design. Birth registration, birth notification and Hospital Episode Statistics were linked using a deterministic algorithm. \r\n\r\nSetting: \r\nNational Health Service (NHS) hospitals in England, UK\r\n\r\nParticipants:\r\nAll live, singleton births in NHS hospitals occurring in England January 2005 to December 2006 (n=1,018,136). \r\n\r\nMain outcome measures:\r\nThe primary outcome was all inpatient hospital admissions from birth to age 10 years, death or study end (March 2015) and the secondary outcome was the main cause of admission, which was defined as the first International Classification of Disease-10 (ICD10) code within each hospital admission record. \r\n\r\nResults:\r\n525,039 (52%) children experienced at least one hospital admission during the study period. Hospital admissions during childhood were strongly associated with gestational age at birth (\u003c28, 28-29, 30-31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, and 42 weeks). Compared to children born full term (40 weeks’ gestation), those born extremely preterm (\u003c28 weeks) had the highest rate of hospital admission throughout childhood (adjusted RR, aRR=4·29, 95%CI: 4·58 to 5·30). Even children born at 38 weeks had a higher rate of hospital admission throughout childhood (aRR=1·19, 95%CI: 1·16 to 1·22). However, the association between gestational age and hospital admission decreased with increasing age (interaction p\u003c0·001). Children born \u003c28 weeks had an aRR of 6·38 (95%CI: 5.80 to 6.85) during infancy, declining to 3·28 (95%CI: 2.82 to 3.82) at ages 7-10, in comparison to those born full term; whilst in children born at 38 weeks, the aRRs were 1·29 (95%CI: 1.27 to 1.31) and 1·16 (95%CI: 1.13 to 1.19), during infancy and ages 7-10 respectively. Infection was the main cause of excess hospital admissions at all ages, but particularly during infancy. Respiratory and gastrointestinal conditions also accounted for a large proportion of admissions during the first two years of life. \r\n\r\nConclusions:\r\nWhilst the association between gestational age and hospital admission rates decreased with age, an excess risk remained throughout childhood, even among children born at 38 and 39 weeks of gestation. Strategies aimed at the prevention and management of childhood infections should target children born preterm and those born a few weeks early.