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Length of stay and readmission among late preterm infants: an instrumental variable approach
Neera Goyal1, José R Zubizarreta, Dylan S Small
1Division of Neonatology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Insights
Longer hospital stays for late preterm infants (34-36 weeks gestation) do not reduce 7-day readmission rates. This study found no evidence that extending length of stay (LOS) improves outcomes for these vulnerable newborns.
Area of Science:
- Neonatal Health
- Pediatric Outcomes
- Public Health
Background:
- Late preterm infants (34-36 weeks gestation) face higher readmission risks than term infants.
- Evidence guiding safe discharge practices for late preterm infants is limited.
- Neonatal readmission poses significant healthcare burdens.
Purpose of the Study:
- To determine if extending length of stay (LOS) impacts 7-day readmission rates in late preterm infants.
- To provide evidence-based guidance for optimizing discharge timing for this population.
- To address the lack of data on safe discharge for late preterm neonates.
Main Methods:
- Retrospective analysis of California hospital discharge and vital records (1993-2005).
- Instrumental variable analysis using birth hour to control for unmeasured confounding.
- Matching algorithm created pairs of infants with varying LOS but similar confounders.
Main Results:
- 80,600 matched pairs of infants with different lengths of stay were analyzed.
- No statistically significant association was found between longer LOS and reduced 7-day readmission.
- The study found no evidence that extending hospital stay benefits late preterm infants regarding readmission.
Conclusions:
- Extended length of stay is not associated with decreased 7-day readmission for late preterm infants.
- Current discharge practices may not require extended hospital stays for this population.
- Further research is needed to establish optimal discharge criteria for late preterm neonates.
Objective:
Evidence to guide safe discharge for late preterm infants (34-36 weeks' gestation) is lacking. Previous studies have demonstrated the increased risk of neonatal readmission for these infants compared with those born at term (> or =37 weeks' gestation). The purpose of this study was to estimate the effect of length of stay (LOS) on 7-day readmissions in this population.
Methods:
This was a retrospective study using hospital discharge data linked with vital records for late preterm infants delivered vaginally in California from 1993 to 2005. Exclusion criteria included complications likely requiring neonatal intensive care. The effect of LOS was assessed by using birth hour as an instrumental variable to account for unmeasured confounding. By using a matching algorithm, we created pairs of infants with different LOS based on birth hour but otherwise matched on known confounders for readmission risk, including birth year, hospital, and clinical and demographic covariates such as gestational age, birth weight, race, and insurance.
Results:
We produced 80600 matched pairs of infants with different LOS based on birth hour. In 122 pairs, both infants were readmitted within 7 days, and in 75362 pairs, neither infant was readmitted. Of the remaining 5116 matched pairs in which only 1 infant was readmitted, 2456 infants with long LOS and 2660 infants with short LOS were readmitted. We found no evidence that longer LOS reduces the odds of readmission (1-sided P value = .99).
Conclusions:
By using an instrumental variable approach and matching algorithm, longer LOS was not associated with decreased readmission within 7 days of discharge for these late preterm infants.
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