To the Editor: In their randomized controlled trial, Dr Cruz and colleagues1 reported that polymyxin B hemoperfusion reduced 28-day mortality in patients with severe sepsis or septic shock. I believe that this conclusion is wrong. The statistically significant difference in mortality rates reported in this study was based on the analysis of a hazard ratio generated by a Cox proportional hazards regression survival model. However, the odds ratio (OR) of the crude 28-day mortality rates did not reach statistical significance (11/34 vs 16/30; OR, 0.42; 95% confidence interval [CI], 0.13-1.29; P = .13). Such a difference between the hazard ratio and the OR can only be explained by a later occurrence of deaths in the treated group, an effect that is suggested in Figure 3.1 This observation is concerning in an unblinded trial, in which investigators could forgo life support later in patients in the treatment group, creating a false appearance of improved survival in that group early in the study. It would therefore be helpful to know the mortality rates at 60 or 90 days; the narrowing difference between mortality rates that seems to be occurring over 28 days in Figure 3 may have decreased further over longer periods.
Comparing their study with a pilot study that found no effect of polymyxin B on mortality,2 the authors argued that the earlier study included only a single hemoperfusion session compared with the 2 sessions used in their study. However, it is the initial resuscitation period that is most critical, and endotoxin in particular plays a role very early in the septic process.3 - 4 I believe that an additional procedure 24 hours later is unlikely to make a difference.
Although the study by Cruz et al remains interesting because it confirmed the hemodynamic improvements seen with this approach,2 ,5 it is unfortunate that it was interrupted so early, in the absence of statistically significant differences in mortality, thus leaving unanswered the important question of whether this therapeutic approach can improve outcomes in patients with severe sepsis.
Financial Disclosures: None reported.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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