Frequency and risk factors for hospital readmission of very preterm infants to age one year

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The problem

The survival of infants born very preterm has greatly improved in recent years. However morbidity following neonatal unit discharge remains high. Previous studies of hospital readmissions have predominantly involved single centres. In this population study we aimed to investigate the frequency, reasons and predictors of hospital readmission of very preterm infant in England to age one year.

The approach

We analysed data on infants, with a completed gestational age from 23+0 and 32+6 weeks days, born in England and admitted to a neonatal unit between 1 January 2010 and 31 December 2010. We used information from a birth cohort we created by linking the National Neonatal Research Database (NNRD) with Hospital Episode Statistics (HES), which we have described elsewhere. We defined readmission as any hospital admission following initial neonatal unit discharge up to the age of one year. We used multivariate logistic regression to investigate the association between admission to hospital and maternal and infant characteristics (maternal age and ethnicity (White, Asian or Asian British, Black or Black British, Mixed and Other Ethnic Groups), smoking in pregnancy, social deprivation (Index of Multiple Deprivation quintile categories), infant sex, gestational age (weeks), birth weight (g), small for gestational age (SGA), multiple birth and any congenital anomalies of the nervous, circulatory, respiratory, digestive, urinary and musculoskeletal systems (as dentified by ICD10 codes).


We identified 7,463 live-born infants admitted to NHS neonatal units in England over the study period. Of these 528 died before reaching one year of age; thus, 6,935 were eligible for follow-up. A total of 3,621 (52.2%) infants were readmitted to hospital at least once up to the age of one year; 1,972 (28.4%) were readmitted more than once. Male sex (OR 1.51, 95% CI 1.36-1.69), SGA (OR 1.41, 95% CI 1.17-1.71), smoking in pregnancy (OR 1.23, 95% CI 1.07-1.41), and 4th social deprivation quintile in relation to 1st quintile (OR 1.24, 95% CI 1.03-1.48) were significantly associated with hospital readmission. We found that with each increasing week of gestational age there was a 17% reduction in readmissions (OR 0.83, 95% CI 0.81-0.85). The most common principal diagnoses during first readmission were respiratory infections (25.1%), gastrointestinal problems (7.7%), infections (other than respiratory or gastrointestinal) (7.5%) and (4) hernia (7.2%) (inguinal and unspecified abdominal).Conclusions Very preterm infants have a high risk of hospital readmission in the first year following neonatal unit discharge. Our results point to a strong association with measures of socioeconomic adversity. Important health service goals are the evaluation of potential methods, such as systematic follow-up in primary or secondary care and enhanced paediatric training for general practitioners, to reduce hospital admissions in this vulnerable group of infants.


  • Buthaina Ibrahim, University College London, London, UK
  • Yevgeniy Statnikov, University College London, London, UK
  • Daniel Gray, University College London, London, UK
  • Neena Modi, University College London, London, UK
  • Sonia Saxena, University College London, London, UK
  • Peter Brocklehurst, BLISS, London, UK
  • Zoe Chivers, Queen Mary University of London, London, UK
  • Kate Costeloe, University of Leicester, Leicester, UK
  • Elizabeth Draper, London Specialised Commissioning Group, London, UK
  • Azeem Majeed, University College London, London, UK
  • Jacquie Kemp, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
  • Deborah Ashby, University College London, London, UK
  • Alys Young, University of Warwick, Warwick, UK
  • Stavros Petrou