Sources of Heterogeneity in Trials Reporting Hydroxyethyl Starch 130/0.4 or 0.42 Associated Excess Mortality in Septic Patients: A Systematic Review and Meta-regression.

Background: This meta-analysis was to determine the association of the cumulative dose of 130/0.4 or 0.42 (hydroxyethyl starch [HES] 130/0.4*) or delta daily fluid balance (i.e., daily fluid balance in HES group over or below control group) with the heterogeneity of risk ratio (RR) for mortality in randomized control trials (RCTs).

Methods: Three databases (PubMed, EMBASE, Cochrane) were searched to identify prospective RCTs reporting mortality in adult patients with sepsis to compare HES130/0.4* with crystalloids or albumin. Meta-analysis was performed using random effects. Sensitivity and meta-regression analyses were used to examine the heterogeneity sources of RR for mortality.

Results: A total number of 4408 patients from 11 RCTs were included. The pooled RR showed no significant difference for overall mortality in patients with administration of HES130/0.4* compared with treatment of control fluids (RR: 1.02, 95% confidence interval: 0.90-1.17; P = 0.73). Heterogeneity was moderate across recruited trials (I2 = 34%, P = 0.13). But, a significant variation was demonstrated in subgroup with crystalloids as control fluids (I2 = 42%, P < 0.1). Sensitivity analysis revealed that trials with high risk of bias did not significantly impact the pooled estimates for mortality. Meta-regression analysis also did not determine a dose-effect relationship of HES130/0.4* with mortality (P = 0.298), but suggested daily delta fluid balance being likely associated with mortality in septic patients receiving HES130/130/0.4* (P = 0.079).

Conclusions: Inappropriate daily positive fluid balance was likely an important source of heterogeneity in these trials reporting HES130/0.4* associated with excess mortality in septic patients.