Thirty RCTs (n=2,430) were included.
There was no evidence of a difference between EN and PN for hospital mortality; the overall RD was 0.6% (95% confidence interval, CI: -1, 2.2, P=0.4). The individual study results were mostly homogeneous (I2=0%). Similar results were seen in the medical, surgical and trauma subgroups.
Hospital length of stay was significantly reduced in patients receiving EN than in those receiving PN; the overall reduction was 1.2 days (95% CI: 0.38, 2.03, P=0.004). There was some heterogeneity between studies (I2=51%), but subgroup analyses were not performed because of the small number of studies. A similar result was also seen for length of stay in the intensive care unit (ICU; 4 studies), with an overall reduced length of stay for EN patients of 1.4 days (95% CI: 0.37, 2.4, P=0.008).
PN was associated with a significant increase in the risk of infective complications; the overall RD was 7.9% (95% CI: 4, 11.8, P=0.001). Similar results were seen in all subgroups. PN was also associated with a significant increase in the risk of noninfective complications (RD 4.9%, 95% CI: 0.3, 9.5, P=0.04) and a significant decrease in the risk of diarrhoea (RD -8.7%, 95% CI: -13.6, -3.8, P=0.001). There was no evidence of a difference between EN and PN with respect to technical complications; the overall RD was 4.1% (95% CI: -1.8, 9.9, P=0.2). Significant heterogeneity (I2=64%) was observed only for technical complications.
The meta-regression (results not reported) found no evidence that age, albumin level on admission, or time to initiate treatment were related to the outcomes. The cumulative meta-analysis did not show any effects of time. There was no evidence of publication bias (P=0.89 Egger's test; P=0.9 Begg's test). The trim-and-fill method suggested one missing study, although the mortality results remained unchanged.