Table 1 Baseline characteristics before and after propensity score matching
Before propensity score matching | After propensity score matching | |||||
|---|---|---|---|---|---|---|
Saline N = 657 | Ringer’s N = 8,053 | SD | Saline N = 578 | Ringer’s N = 578 | SD | |
Age, years, median (IQR) | 66.0 (49.0–77.0) | 63.0 (46.0–76.0) | 0.119 | 66.0 (49.0–78.0) | 64.0 (49.0–77.0) | 0.041 |
Male, n (%) | 445 (67.7) | 5195 (64.5) | 0.068 | 388 (67.1) | 386 (66.8) | 0.007 |
Smoking history, n (%) | ||||||
Nonsmoker | 305 (46.4) | 3633 (45.1) | 0.026 | 263 (45.5) | 252 (43.6) | 0.038 |
Current/past smoker | 262 (39.9) | 3467 (43.1) | −0.064 | 235 (40.7) | 245 (42.4) | −0.035 |
Unknown | 90 (13.7) | 953 (11.8) | 0.056 | 80 (13.8) | 81 (14.0) | −0.005 |
BMI at admission, kg/m2, n (%) | ||||||
< 18.5 | 100 (15.2) | 1019 (12.7) | 0.074 | 87 (15.1) | 87 (15.1) | 0 |
18.5–24.9 | 365 (55.6) | 4842 (60.1) | −0.093 | 323 (55.9) | 339 (58.7) | −0.056 |
25–29.9 | 124 (18.9) | 1534 (19.0) | −0.004 | 108 (18.7) | 99 (17.1) | 0.04 |
≥ 30.0 | 43 (6.5) | 436 (5.4) | 0.048 | 37 (6.4) | 37 (6.4) | 0 |
Missing | 25 (3.8) | 222 (2.8) | 0.059 | 23 (4.0) | 16 (2.8) | 0.068 |
Physical function at admission, n (%) | ||||||
Independent (Barthel Index 100) | 382 (58.1) | 3972 (49.3) | 0.178 | 326 (56.4) | 320 (55.4) | 0.021 |
Slight/moderate dependence (Barthel Index 61–99) | 28 (4.3) | 650 (8.1) | −0.159 | 26 (4.5) | 28 (4.8) | −0.014 |
Total/severe dependence (Barthel Index 0–60) | 112 (17.0) | 2032 (25.2) | −0.201 | 108 (18.7) | 117 (20.2) | −0.038 |
Missing | 135 (20.5) | 1399 (17.4) | 0.081 | 118 (20.4) | 113 (19.6) | 0.022 |
JCS at admission, n (%) | ||||||
Clear 0 | 462 (70.3) | 6679 (82.9) | −0.301 | 423 (73.2) | 419 (72.5) | 0.017 |
Confusion 1–3 | 128 (19.5) | 1132 (14.1) | 0.146 | 106 (18.3) | 106 (18.3) | 0 |
Somnolence 10–30 | 35 (5.3) | 172 (2.1) | 0.169 | 28 (4.8) | 29 (5.0) | −0.009 |
Coma 100–300 | 32 (4.9) | 70 (0.9) | 0.241 | 21 (3.6) | 24 (4.2) | −0.031 |
Charlson comorbidity index, n (%) | ||||||
0 | 269 (40.9) | 4519 (56.1) | −0.307 | 250 (43.3) | 243 (42.0) | 0.025 |
1 | 193 (29.4) | 2287 (28.4) | 0.022 | 181 (31.3) | 182 (31.5) | −0.004 |
≥ 2 | 195 (29.7) | 1247 (15.5) | 0.344 | 147 (25.4) | 153 (26.5) | −0.025 |
Comorbidity of CKD, n (%) | 102 (15.5) | 128 (1.6) | 0.514 | 56 (9.7) | 58 (10.0) | −0.013 |
Fiscal year at admission, n (%) | ||||||
2010–2014 | 297 (45.2) | 2869 (35.6) | 0.196 | 258 (44.6) | 264 (45.7) | −0.021 |
2015–2017 | 205 (31.2) | 2744 (34.1) | −0.061 | 183 (31.7) | 191 (33.0) | −0.03 |
2018–2020 | 155 (23.6) | 2440 (30.3) | −0.152 | 137 (23.7) | 123 (21.3) | 0.055 |
Admission on a weekend, n (%) | 167 (25.4) | 2322 (28.8) | −0.077 | 146 (25.3) | 154 (26.6) | −0.031 |
Ambulance use, n (%) | 411 (62.6) | 4525 (56.2) | 0.13 | 364 (63.0) | 358 (61.9) | 0.021 |
Prognosis factor, n (%) | ||||||
0 | 128 (19.5) | 2717 (33.7) | −0.327 | 123 (21.3) | 127 (22.0) | −0.016 |
1 | 100 (15.2) | 2123 (26.4) | −0.277 | 95 (16.4) | 92 (15.9) | 0.013 |
2 | 76 (11.6) | 1154 (14.3) | −0.082 | 69 (11.9) | 71 (12.3) | −0.01 |
3 | 74 (11.3) | 602 (7.5) | 0.13 | 68 (11.8) | 58 (10.0) | 0.059 |
4 | 50 (7.6) | 378 (4.7) | 0.122 | 44 (7.6) | 49 (8.5) | −0.036 |
5 | 48 (7.3) | 166 (2.1) | 0.25 | 35 (6.1) | 40 (6.9) | −0.041 |
6 | 28 (4.3) | 96 (1.2) | 0.189 | 21 (3.6) | 18 (3.1) | 0.032 |
7 | 14 (2.1) | 43 (0.5) | 0.14 | 10 (1.7) | 8 (1.4) | 0.03 |
8 | 8 (1.2) | 15 (0.2) | 0.124 | 6 (1.0) | 6 (1.0) | 0 |
9 | 2 (0.3) | 12 (0.1) | 0.033 | 1 (0.2) | 1 (0.2) | 0 |
Unknown | 129 (19.6) | 747 (9.3) | 0.298 | 106 (18.3) | 108 (18.7) | −0.01 |
CT grade score, n (%) | ||||||
0 | 135 (20.5) | 1,633 (20.3) | 0.007 | 124 (21.5) | 138 (23.9) | −0.06 |
1 | 88 (13.4) | 1,516 (18.8) | −0.148 | 76 (13.1) | 54 (9.3) | 0.104 |
2 | 171 (26.0) | 2,904 (36.1) | −0.218 | 158 (27.3) | 161 (27.9) | −0.011 |
3 | 63 (9.6) | 656 (8.1) | 0.051 | 56 (9.7) | 51 (8.8) | 0.03 |
4 | 32 (4.9) | 251 (3.1) | 0.09 | 26 (4.5) | 24 (4.2) | 0.018 |
Unknown | 168 (25.6) | 1,093 (13.6) | 0.306 | 138 (23.9) | 150 (26.0) | −0.053 |
Ventilator use, n (%) | 75 (11.4) | 170 (2.1) | 0.377 | 46 (8.0) | 45 (7.8) | 0.007 |
Renal replacement therapy, n (%) | 154 (23.4) | 93 (1.2) | 0.721 | 77 (13.3) | 75 (13.0) | 0.011 |
Catecholamine use, n (%) | 103 (15.7) | 415 (5.2) | 0.35 | 78 (13.5) | 71 (12.3) | 0.04 |