Intravenous immunoglobulin for preventing infection in preterm and/or low-birth-weight infants

Nosocomial infections continue to be a significant cause of morbidity and mortality among preterm and/or low birth weight infants. Maternal transport of immunoglobulins to the fetus mainly occurs after 32 weeks gestation and endogenous synthesis does not begin until several months after birth. Administration of intravenous immunoglobulin provides IgG that can bind to cell surface receptors, provide opsonic activity, activate complement, promote antibody dependent cytotoxicity, and improve neutrophilic chemoluminescence. Intravenous immunoglobulin thus has the potential of preventing or altering the course of nosocomial infections.

To assess the effectiveness/safety of intravenous immunoglobulin (IVIG) administration (compared to placebo or no intervention) to preterm (< 37 weeks gestational age at birth) and/or low birth weight (LBW) (< 2500 g BW) infants in preventing nosocomial infections.

Medline, Embase, Cochrane Library and Reference Update Databases were searched in November 1997 using keywords: immunoglobulin and infant-newborn and random allocation or controlled trial or randomized controlled trial (RCT). The reference lists of identified RCTs, personal files and Science Citation Index were searched. No language restrictions were applied.

The criteria used to select studies for inclusion in this overview were: 1) DESIGN: RCTs in which administration of IVIG was compared to a control group that received a placebo or no intervention. 2) POPULATION: preterm (< 37 weeks gestational age) and/or LBW (<2500 g) infants. 3) INTERVENTION: IVIG for the prevention of bacterial/fungal infection during initial hospital stay (8 days or longer). (Studies that were primarily designed to assess the effect of IVIG on humoral immune markers were excluded as were studies in which the follow-up period was one week or less). 4) At least one of the following outcomes was reported: sepsis, any serious infection, death from all causes, death from infection, length of hospital stay, intraventricular haemorrhage (IVH), necrotizing enterocolitis (NEC), bronchopulmonary dysplasia (BPD).

Two reviewers independently abstracted information for each outcome reported in each study, and one researcher (AO) checked for any discrepancies and pooled the results. Relative risk (RR) and Risk Difference (RD) with 95% confidence intervals (CI) using the fixed effects model are reported. When a statistically significant RD was found the number needed to treat (NNT) was also calculated with 95% CIs. The results include all accepted studies in which the outcome of interest was reported. When statistically significant heterogeneity was found for an outcome, secondary (sensitivity) analyses were performed including only studies of the highest quality.

Fifteen studies met inclusion criteria. These included 5,054 preterm and/or LBW infants and reported on at least one of the outcomes of interest for this systematic review. When all studies were combined there was a statistically significant reduction in sepsis, one or more episodes [RR 0.83 (95% CI 0.72, 0.97); RD -0.028 (95% CI -0.006, -0.051); NNT 36 (95% CI 20, 167)]. There was significant between-study heterogeneity. When, in a sensitivity analysis, the high quality studies were combined, the results remained significant [RR 0.78 (95% CI 0.62, 0.98); RD -0.031(95% CI -0.003, -0.059); NNT 32 (95% CI 17, 333]. For this analysis there was no statistically significant between-study heterogeneity. A statistically significant reduction was also found for any serious infection, one or more episodes, when all studies were combined [RR 0.85 (95% CI 0.75, 0. 95); RD -0.032 (95% CI -0.010, -0.054,); NNT 31 (95% CI 19, 100). There was statistically significant between-study heterogeneity. When, in a sensitivity analysis, the high quality studies were combined the results remained statistically significant [RR 0.80 (95% CI