Factors affecting postnatal changes in serum creatinine in preterm infants with gestational age <32 weeks

The Aim of this study was to investigate maternal and neonatal factors associated with serum creatinine (SeCr) changes in a representative cohort of preterm newborns during their first week of life.

Retrospective study. All the infants born less than 32 weeks of gestational age (GA) and cared for in our neonatal intensive care unit between January 2001 and December 2005 were eligible for the analysis. Epidemiological data of all mother-infant pairs and neonatal SeCr values were recorded.

A total of 652 infants were studied. Multivariate regression analysis showed that the main independent factors associated with high SeCr at day 1 were hypertensive disease of pregnancy (P<0.0001) and advancing hour of life (P<0.0001), with minimal contribution of placental abruption (P<0.05) and higher GA (P<0.05). Lower GA (P<0.0001) and ibuprofen-treated patent ductus arteriosus (PDA; P<0.0001) were the main analyzed factors independently associated with higher SeCr peak (defined as the highest SeCr during the week), with less contribution of respiratory distress syndrome (P<0.01) and early onset infection (P<0.05). In infants with hemodynamically significant PDA (hsPDA) SeCr before ibuprofen administration was higher when compared to GA-matched controls without hsPDA (P< 0.0001).

SeCr peak was inversely correlated to GA in preterm infants born less than 32 weeks of GA. Neonatal rather than maternal morbidity affected SeCr peak. In hsPDA, SeCr increase preceded ibuprofen administration.