Acute kidney injury is associated with bronchopulmonary dysplasia/mortality in premature infants.

BACKGROUND

Acute kidney injury (AKI) impairs electrolyte balance, alters fluid homeostasis and decreases toxin excretion. More recent data suggest it also affects the physiology of distant organs.

METHODS

We performed a prospective cohort study which invloved 122 premature infants [birth weight (BW) ≤1200 g and/or gestational age (GA) <31 weeks] to determine relationships between AKI and bronchopulmonary dysplasia (BPD)/mortality. Days until oxygen discontinuation was compared between those with and without AKI in survivors who received oxygen for ≥24 h.

RESULTS

Acute kidney disease, defined by a rise in serum creatinine (SCr) of ≥0.3 mg/dl or an increase in SCr of ≥150%, occurred in 36/122 (30%) of the premature infants. Those with AKI had a 70% higher risk of oxygen requirement or of dying at 28 days of life [relative risk (RR) 1.71, 95% confidence interval (CI) 1.22-2.39; p < 0.002]. This association remained after controlling for GA, pre-eclampsia, 5 min Apgar score and percentage maximum weight change (max % weight Δ) in the first 4 days (RR 1.45, 95% CI 1.07-1.97); p < 0.02). Similar findings were noted for receipt of mechanical ventilation/death by day 28 (adjusted RR 1.53, 95% CI 1.05-2.22; p < 0.03). Those without AKI were 2.5-fold more likely to come off oxygen [hazard ratio (HR) 1.3-5; p < 0.02) than those with AKI, even when controlling for GA, pre-eclampsia, 5 min Apgar and max % weight Δ (multivariate HR 2.0, 95% CI 0.9-4.0; p < 0.06).

CONCLUSIONS

In premature infants, AKI is associated with BPD/mortality. As AKI could lead to altered lung physiology, interventions to ameliorate AKI could improve long-term BPD.