Table 3.
Imbalance of patient characteristics before and after propensity weighting in the assessment of in-ICU mortality
| Variables | Before weighting | After weighting | ||||
|---|---|---|---|---|---|---|
| No exposure to NE (n = 3448) |
Exposure to NE (n = 1605) |
SMD | No exposure to NE (n = 3502) |
Exposure to NE (n = 1582) |
SMD | |
| Age, years | 68 [60–76] | 70 [61–77] | 0.120 | 69 [61–76] | 69 [61–76] | 0.002 |
| Male gender | 2407 (67) | 1080 (67) | 0.054 | 2456 (70) | 2456 (70) | 0.036 |
| BMI, kg m−2 | 27.48 [24.44–30.72] | 26.83 [23.83–30.42] | 0.017 | 27.50 [24.39–30.73] | 27.50 [24.39–30.73] | 0.005 |
| Hypertension | 1925 (56) | 890 (56) | 0.008 | 1912 (55) | 1919 (55) | 0.018 |
| Coronary disease | 385 (11.2) | 213 (13) | 0.064 | 380 (11) | 381 (11) | 0.078 |
| Diabetes | 690 (20) | 294 (18) | 0.043 | 671 (19) | 671 (19) | 0.003 |
| Dyslipidemia | 274 (8) | 107 (7) | 0.049 | 259 (7) | 258.7 (7) | 0.007 |
| Chronic kidney disease | 126 (4) | 98 (6) | 0.114 | 157 (5) | 157 (5) | 0.022 |
| Peripheral vascular disease | 188 (6) | 76 (5) | 0.033 | 187 (5) | 187 (5) | 0.018 |
|
Hemoglobin, g dl−1 |
11.52 ± 1.54 | 11.23 ± 1.64 | 0.181 | 11.3 ± 1.56 | 11.4 ± 1.43 | 0.004 |
|
Platelet, 103 mm−3 |
157 ± 58 | 150 ± 66 | 0.111 | 146 ± 34 | 144 ± 35 | 0.007 |
|
Creatinine, µ mol l−1 |
77 [64–94] | 82 [67–105] | 0.187 | 79 [65–99] | 79 [65–99] | 0.012 |
| CPB time, min | 84 [56–118] | 100 [67–136] | 0.336 | 88 [58–125] | 88 [58–125] | 0.036 |
| Aortic clamp time, min | 57 [35–83] | 64 [42–94] | 0.111 | 59 [37–87] | 59 [37–87] | 0.005 |
| Surgery type | 0.185 | |||||
| CABG | 962 (28) | 468 (29) | 1002 (29) | 1002 (29) | 0.010 | |
| Valve surgery | 1254 (36) | 620 (39) | 1284 (37) | 1284 (37) | ||
| Combined surgery | 336 (10) | 212 (13) | 369 (11) | 369 (11) | ||
| Others | 896 (26) | 305 (19) | 847 (24) | 847 (24) | ||
| SAPS II | 34 [28–40] | 40 [33–48] | 0.595 | 35 [30–43] | 35 [30–43] | 0.030 |
| Inotropes | 0 (0) | 128 (8) | 0.306 | 0 (0) | 74 (5) | 0.223 |
An absolute MSD < 10% was considered to support the assumption of a balance between the groups. SMD: standardized mean differences. Data are presented as medians [interquartile ranges] or as numbers (percentages). NE: norepinephrine, CABG: coronary bypass graft, CPB: coronary bypass, SAPS II: Simplified Acute Physiology Score. Male gender and coronary disease were not selected for the propensity weighting as the P value for their association with acute kidney injury was over 20%