Table 2.

Estimated treatment effects of Polymyxin B hemadsorption in the derivation and validation cohorts

	Treatment effects on 28-day survival [95% CI]	Hazard ratio for 28-day mortality [95% CI]	Treatment effects on 28-day survival without RRT initiation [95% CI]
Derivation cohort
Full sample (n = 1911)	+ 5.3% [− 1.9% to + 13%]	–	–
Targeted subpopulation (n = 1203)	+ 9.2% [+ 1.0% to + 17%]	–	–
Full sample (n = 286)	+ 7.4% [− 4.3% to + 19%], (PMX-HA vs. control, 70% vs. 62%)	0.71 [0.48 to 1.06]	+ 2.9% [− 9.0% to + 15%] (PMX-HA vs. control, 39% vs. 36%)
Validation cohort
Targeted subpopulation (n = 214)	+ 16% [+ 2.2% to + 30%] (PMX-HA vs. control, 68% vs. 52%)	0.62 [0.40 to 0.95]	+ 12% [− 1.4% to + 25%] (PMX-HA vs. control, 37% vs. 25%)
Patients on RRT at baseline (n = 54)	+ 7.4% [− 24% to + 39%] (PMX-HA vs. control, 47% vs. 40%)	0.56 [0.25 to 1.27]	–
Patients not on RRT at baseline (n = 160)	+ 15% [− 0.3% to + 31%] (PMX-HA vs. control, 73% vs. 58%)	0.68 [0.40 to 1.16]	+ 11% [− 5.8% to + 27%] (PMX-HA vs. control, 45% vs. 35%)

Higher treatment effects on 28-day survival are equivalent to higher absolute risk reduction of 28-day mortality. “Targeted subpopulation” indicates patients with PT-INR > 1.4 or lactate > 3 mmol/L on ICU admission. The estimate of each treatment effect of PMX-HA in the derivation cohort are computed using the augmented inverse probability weighting formula with the causal forest model. The estimated treatment effects in the validation cohort were calculated using the per-protocol analysis utilizing the nature of a RCT

RRT, Renal Replacement Therapy; PT-INR, Prothrombin Time and International Normalized Ratio; PMX-HA, Polymyxin B Hemadsorption; RCT, Randomized Controlled Trial