Table 1 Relevant patient characteristics according to study group

Variables Unmatched group Matched group
All patients
(n = 1,723)
non-PMX-HP
(n = 1,201)
PMX-HP
(n = 522)
SD P value All patients
(n = 524)
non-PMX-HP
(n = 262)
PMX-HP
(n = 262)
SD P value
Age, years 69.7 (13.8) 69.5 (14.0) 70.0 (13.1) 0.036 0.502 69.9 (13.1) 70.3 (13.4) 69.4 (12.8) 0.070 0.422
Male, n (%) 1019 (59.1) 705 (58.7) 314 (60.2) 0.030 0.574 304 (58.0) 150 (57.3) 154 (58.8) 0.031 0.723
Body weight, kg 56.6 (14.1) 56.6 (14.5) 56.6 (13.4) 0.007 0.903 56.5 (14.6) 56.0 (14.4) 57.0 (14.8) 0.064 0.465
Emergency center ICU, n (%) 729 (42.3) 486 (40.5) 243 (46.6) 0.123 0.019 239 (45.6) 121 (46.2) 118 (45.0) 0.023 0.793
Admission route to the ICU, n (%)
Emergency department 735 (42.7) 543 (45.2) 192 (36.8) 0.172 0.000 215 (41.0) 109 (41.6) 106 (40.5) 0.023 0.790
Other hospital 423 (24.6) 287 (23.9) 136 (26.1) 0.050 0.339 121 (23.1) 62 (23.7) 59 (22.5) 0.027 0.756
Hospital ward 565 (32.8) 371 (30.9) 194 (37.2) 0.133 0.011 188 (35.9) 91 (34.7) 97 (37.0) 0.048 0.585
ICU policy, n (%)
Open ICU 549 (31.9) 387 (32.2) 162 (31.0) 0.026 0.628 160 (30.5) 74 (28.2) 86 (32.8) 0.100 0.255
Closed ICU 897 (52.1) 637 (53.0) 260 (49.8) 0.065 0.217 281 (53.6) 147 (56.1) 134 (51.1) 0.100 0.255
Others 277 (16.1) 177 (14.7) 100 (19.2) 0.118 0.022 83 (15.8) 41 (15.6) 42 (16.0) 0.011 0.905
Number of ICU beds, number 12 (8–18) 12 (10–19) 10 (7–12) 0.429 <0.001 10.5 (8–16) 12 (8–15) 10 (7–16) 0.041 0.361
Pre-existing organ dysfunction, n (%)
Liver insufficiency 83 (4.8) 49 (4.1) 34 (6.5) 0.109 0.032 30 (5.7) 12 (4.6) 18 (6.9) 0.099 0.262
Chronic respiratory disorder 66 (3.8) 46 (3.8) 20 (3.8) 0.000 1.000 18 (3.4) 6 (2.3) 12 (4.6) 0.126 0.158
Chronic heart failure 99 (5.7) 68 (5.7) 31 (5.9) 0.012 0.821 29 (5.5) 13 (5.0) 16 (6.1) 0.050 0.567
Chronic hemodialysis 149 (8.6) 99 (8.2) 50 (9.6) 0.047 0.365 53 (10.1) 25 (9.5) 28 (10.7) 0.038 0.664
Immunocompromised 299 (17.4) 218 (18.2) 81 (15.5) 0.070 0.185 83 (15.8) 43 (16.4) 40 (15.3) 0.031 0.720
None 1,108 (64.3) 773 (64.4) 335 (64.2) 0.004 0.941 338 (64.5) 177 (67.6) 161 (61.5) 0.128 0.145
Severity
APACHE II score 25.4 (8.9) 25.2 (8.9) 25.9 (8.9) 0.083 0.115 25.2 (9.2) 25.5 (8.9) 25.0 (9.5) 0.060 0.493
SOFA score 11.5 (3.5) 11.2 (3.5) 12.0 (3.5) 0.246 <0.001 11.6 (3.4) 11.7 (3.4) 11.5 (3.4) 0.067 0.442
SIRS positivea, n (%) 1,654 (96.0) 1151 (95.8) 503 (96.4) 0.027 0.611 499 (95.2) 253 (96.6) 246 (93.9) 0.126 0.157
JAAM DIC positiveb, n (%) 1,092 (63.4) 723 (60.2) 369 (70.7) 0.222 <0.001 345 (65.8) 176 (67.2) 169 (64.5) 0.056 0.519
1. Data are presented as mean (standard deviation), median (first quartile to third quartile), or number (percentage)
2. aSIRS criteria ≥2
3. bJAAM DIC score ≥4
4. APACHE Acute Physiology and Chronic Health Evaluation, DIC disseminated intravascular coagulation, ICU intensive care unit, JAAM Japanese Association for Acute Medicine, PMX-HP polymyxin B hemoperfusion, SD standardized difference, SIRS systemic inflammatory response syndrome, SOFA Sequential Organ Failure Assessment