Predicting neonatal outcomes: birthweight, body mass index or ponderal index?
OBJECTIVE
To compare birthweight (BW), body mass index (BMI) and ponderal index (PI) as predictors of selected short-term (ST) outcomes, namely Neonatal Intensive Care Unit (NICU) admission and prolonged hospitalization (PH), among newborn (NB) infants.


METHODS
Data was collected prospectively on 9,226 infants born during one year at nine tertiary care hospitals in Greater Beirut, Lebanon. The predictive abilities of BW, BMI and PI were compared using the area under the receiver operator characteristic (ROC) curves and sensitivity analysis was performed at the optimal cut-off points for the best anthropometric measurement.


RESULTS
The area under the ROC curve suggested superior discriminative power for BW as compared to BMI or PI, as a predictor of NICU admission (ROC area = 0.73) and PH (ROC area = 0.74). The optimal BW cut-off point was 2750 g (sensitivity: 0.49; specificity: 0.89) and 2950 g (sensitivity: 0.62; specificity: 0.78) for NICU admission and PH, respectively.


CONCLUSIONS
In our population of NB infants, BW--a crude measure of fetal growth--is a better predictor than either BMI--a measure of adiposity in adults and children--or PI--a measure of thinness at birth--for selected ST outcomes in NB infants.
Tamim
Hala
H
Department of Epidemiology and Biostatistics, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon.
Beydoun
Hind
H
Itani
Mohammad
M
Khogali
Mustafa
M
Chokr
Imad
I
Yunis
Khalid A
KA
D001724:Birth Weight; D015992:Body Mass Index; D005260:Female; D005865:Gestational Age; D006257:Head / Q000033:anatomy & histology; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000401:mortality* / Q000473:pathology; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D007861:Lebanon / Q000453:epidemiology; D008297:Male; D010343:Patient Admission; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index