Predicting outcome in very low birthweight infants using an objective measure of illness severity and cranial ultrasound scanning

Abstract

AIM To investigate the feasibility of developing an objective tool for predicting death and severe disability using routinely available data, including an objective measure of illness severity, in very low birthweight babies.

METHOD A cohort study of 297 premature babies surviving the first three days of life was made. Predictive variables considered included birthweight, gestation, 3 day cranial ultrasound appearances and 3 day CRIB (clinical risk index for babies) score. Models were developed using regression techniques and positive predictive values (PPV) and likelihood ratios (LR) were calculated.

RESULTS On univariate analysis, birthweight, gestation, 3 day CRIB score and 3 day cranial ultrasound appearances were each associated with death. On multivariate analysis, 3 day CRIB score and 3 day cranial ultrasound appearances remained independently associated. A 3 day CRIB score > 4 along with intraventricular haemorrhage (IVH) grade 3 or 4 was associated with a PPV of 64% and an LR of 9.8 (95% confidence limits 3.5, 27.9). Only 3 day CRIB score and 3 day cranial ultrasound appearances were associated with severe disability on univariate analysis. Both remained independently associated on multivariate analysis. A 3 day CRIB score > 4 along with an IVH grade of 3 or 4 was associated with a PPV of 60% and an LR of 24.2 (95% CI 4.4, 133.3).

CONCLUSION Incorporating objective measures of illness severity may improve current prediction of death and disability in premature infants.