A Cochrane review included 43 studies Subgroup analysis of 10 polyclonal IVIG trials in adults (n = 1 430) and seven trials on IgM-enriched polyclonal IVIG (n = 528) showed significant reductions in mortality compared to placebo or no intervention (RR 0.81, 95% CI 0.70 to 0.93 and RR 0.66, 95% CI 0.51 to 0.85, respectively). Subgroup analysis of polyclonal IVIG in neonates showed no significant reduction in mortality for standard (RR 1.00, 95% CI 0.92 to 1.08; 5 studies, n = 3667) and IgM-enriched polyclonal IVIG (RR 0.57, 95% CI 0.31 to 1.04; 3 studies, n = 164). Sensitivity analysis of trials with low risk of bias showed no reduction in mortality with polyclonal IVIG in adults (RR 0.97, 95% CI 0.81 to 1.15; 5 studies, n = 945) and neonates (RR 1.01, 95% CI 0.93 to 1.09; 3 studies, n = 3561). Mortality was not reduced among patients (8 studies, n = 4 671) who received anti-endotoxin antibodies (RR 0.99, 95% CI 0.91 to 1.06) while anti-cytokines (9 studies, n = 7 893) demonstrated a marginal reduction in mortality (RR 0.92, 95% CI 0.86 to 0.97).
Comment: The quality of evidence is downgraded by study quality, by inconsistency (variability in results across studies), and by potential reporting bias.