Very low-quality evidence did not show that protein supplementation clearly increased the risk of feeding intolerance (RR 2.70, 95% CI 0.13 to 58.24; one RCT, 17 infants), or necrotizing enterocolitis (RR 1.11, 95% CI 0.07 to 17.12; one RCT, 76 infants), or clearly altered serum albumin concentrations (MD 2.5 g/L, 95% CI -5.66 to 10.66; one RCT, 11 infants), compared with the unsupplemented groups.
High sensitivity and specificity were reported for interleukin-10 (100% and 90%), interleukin1-receptor antagonist (100% and 91.7%), intestinal fatty acid-binding protein (100% and 91%) and ischemia-modified albumin (94.7% and 92%), when tested to predict the evolution from definite to advanced NEC.