Correction to: Association of gastric residual volumes with necrotising enterocolitis in extremely preterm infants—a case–control study

Abstract Necrotising enterocolitis (NEC) is a potentially serious illness with significant mortality and morbidity in preterm infants. Previous studies have reported association of volume and colour (bile and blood stained) of gastric residuals (GR) with NEC. We aimed to study this association in our cohort of extremely preterm (EP) infants. In a case-control study using retrospective data (January 2006-December 2011), EP (Gestation <28 weeks) infants with confirmed NEC ≥ Stage II (Cases) were compared with infants without NEC (Controls) matched for birth weight (BW) and gestational age (GA). Forty cases of NEC ≥ Stage II diagnosed at a median (IQR) age of 16.5 (10.3-23) days were compared with 40 controls matched for gestation (±3 days), and birth weight (±680 g). Median maximum GR volume (GRV) from birth to the day of occurrence of NEC was significantly higher in cases vs. controls (5.9 vs.3.7 ml; p<0.001). Increased maximum GRV was associated with NEC ≥ Stage II in adjusted analysis (aOR 1.36, 95%CI 1.06-1.75, p=0.017). There was no significant difference in GRV between cases and controls throughout the clinical course, including 72, 48 and 24 hours before the onset of NEC. However, green (65.0% vs. 27.5%, p=0.001) and haemorrhagic GRs (45.0% vs. 27.5%, p=0.092) were higher 24 hours before the diagnosis of NEC.Conclusion: GRV was not associated with NEC ≥ Stage II. However, green and haemorrhagic GRs were significantly higher 24 hours before the diagnosis of the illness. Adequately powered prospective studies are needed to confirm the significance of our findings.

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Application of the matched nested case-control design to the secondary analysis of trial data

10.21203/rs.2.18727/v2 ◽

2020 ◽

Author(s):

Christopher Partlett ◽

Nigel J Hall ◽

Alison Leaf ◽

Edmund Juszczak ◽

Louise Linsell

Keyword(s):

Clinical Trial ◽

Case Control Study ◽

Secondary Analysis ◽

Control Design ◽

Case Control ◽

Necrotising Enterocolitis ◽

Trial Data ◽

Standard Case ◽

Nested Case Control ◽

Control Study

Abstract Background A nested case-control study is an efficient design that can be embedded within an existing cohort study or randomised trial. It has a number of advantages compared to the conventional case-control design, and has the potential to answer important research questions using untapped prospectively collected data. Methods We demonstrate the utility of the matched nested case-control design by applying it to a secondary analysis of the Abnormal Doppler Enteral Prescription Trial. We investigated the role of milk feed type and changes in milk feed type in the development of necrotising enterocolitis in a group of 398 high risk growth-restricted preterm infants. Results Using matching, we were able to generate a comparable sample of controls selected from the same population as the cases. In contrast to the standard case-control design, exposure status was ascertained prior to the outcome event occurring and the comparison between the cases and matched controls could be made at the point at which the event occurred. This enabled us to reliably investigate the temporal relationship between feed type and necrotising enterocolitis. Conclusions A matched nested case-control study can be used to identify credible associations in a secondary analysis of clinical trial data where the exposure of interest was not randomised, and has several advantages over a standard case-control design. This method offers the potential to make reliable inferences in scenarios where it would be unethical or impractical to perform a randomised clinical trial.

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