Table 2 Patient characteristics before and after propensity score matching by admission albumin levels (low < 35 g/L vs. normal ≥ 35 g/L)
Variables | Before PSM | After PSM | ||||
|---|---|---|---|---|---|---|
Albumin < 35 (n = 256) | Albumin ≥ 35 (n = 1014) | SMD | Albumin < 35 (n = 228) | Albumin ≥ 35 (n = 228) | SMD | |
Demographic | ||||||
 Male gender (n, %) | 111(43.4) | 395(39.0) | 0.089 | 95(41.7) | 90(39.5) | 0.045 |
 Age, × year (Mean, SD) | 78.58(9.53) | 75.00(13.00) | 0.655 | 74.00(17.00) | 74.50(14.00) | 0.019 |
 Smoking (n, %) | 31(12.1) | 187(18.4) | 0.177 | 29(12.7) | 27(11.8) | 0.027 |
 Alcohol (n, %) | 22(8.6) | 126(12.4) | 0.125 | 21(9.2) | 23(10.1) | 0.030 |
Comorbidities | ||||||
 Hypertension (n, %) | 138(53.9) | 498(49.10) | 0.096 | 125(54.8) | 134(58.8) | 0.080 |
 Diabetes (n, %) | 50(19.5) | 241(23.8) | 0.103 | 47(20.6) | 53(23.2) | 0.063 |
 COPD (n, %) | 39(15.2) | 110(10.8) | 0.130 | 33(14.5) | 27(11.8) | 0.078 |
 Cardiovascular disease (n, %) | 94(36.7) | 296(29.2) | 0.160 | 80(35.1) | 76(33.3) | 0.037 |
 Stroke (n, %) | 91(35.5) | 239(23.6) | 0.264 | 74(32.5) | 73(32.0) | 0.009 |
 Dementia (n, %) | 13(5.1) | 35(3.5) | 0.080 | 10(4.4) | 7(3.1) | 0.069 |
 Intracerebral hemorrhage (n, % | 13(5.1) | 55(5.4) | 0.015 | 13(5.7) | 8(3.5) | 0.105 |
 Chronic liver disease (n, %) | 17(6.6) | 41(4.0) | 0.116 | 15(6.6) | 14(6.1) | 0.018 |
 Chronic kidney disease (n, %) | 16(6.3) | 48(4.7) | 0.067 | 15(6.6) | 20(8.8) | 0.082 |
Operation | ||||||
 Fracture type | ||||||
  Femoral neck fracture (n, %) | 91(35.5) | 588(58.0) | 0.410 | 86(37.7) | 85(37.3) | 0.036 |
  Intertrochanteric fracture (n, % | 146(57.0) | 371(36.6) | 126(55.3) | 123(53.9) | ||
  Subtrochanteric fracture (n, %) | 19(7.4) | 55(5.4) | 16(7.0) | 20(8.8) | ||
 Surgery type | ||||||
  Total Hip Arthroplasty (n, %) | 24(9.4) | 137(13.5) | 0.011 | 22(9.6) | 13(5.7) | 0.026 |
  Hemiarthroplasty (n, %) | 52(20.3) | 267(26.3) | 48(21.1) | 59(25.9) | ||
  Intramedullary nail fixation (n, %) | 113(44.1) | 301(29.7) | 96(42.1) | 96(42.1) | ||
  Internal fixation with steel plate (n, %) | 48(18.8) | 120(11.8) | 44(19.3) | 41(18.0) | ||
  Internal fixation with hollow nails (n, %) | 19(7.4) | 189(18.6) | 18(7.9) | 19(8.3) | ||
Intraoperative blood loss, × ml (Mean, SD) | 196.56(158.95) | 169.94(150.94) | 0.172 | 200.00(200.00) | 196.00(200.00) | 0.072 |
Transfusion (n, %) | 64(25.0) | 146(14.4) | 0.269 | 55(24.1) | 61(26.8) | 0.060 |
Postoperative ICU (n, %) | 26(10.2) | 37(3.6) | 0.258 | 19(8.3) | 22(9.6) | 0.046 |
Admission time | ||||||
 < 6 h (n, %) | 115(44.9) | 557(54.6) | 0.260 | 93(40.8) | 84(36.8) | 0.029 |
 6–24 h (n, %) | 32(12.5) | 163(16.1) | 30(13.2) | 42(18.4) | ||
  ≥ 24 h (n, %) | 109(42.6) | 294(29.0) | 105(46.1) | 102(44.7) | ||
Bedridden time, × day (Mean, SD) | 6.77(5.04) | 5.68(3.70) | 0.247 | (3.00) | 5.00(3.25) | 0.019 |
Intraoperative time, × hour (Mean, SD) | 1.77(0.86) | 1.64(0.79) | 0.153 | 1.53(1.08) | 1.50(1.08) | 0.031 |
ASA classification | ||||||
 III-IV (n, %) | 180(70.3) | 530(52.3) | 0.377 | 157 (68.9) | 154(67.5) | 0.028 |
 I-II (n, %) | 76(29.7) | 484(47.7) | 71(31.1) | 74(32.5) | ||
Laboratory findings | ||||||
 WBC count, × 10^9/L (Mean, S) | 8.49(3.24) | 8.85(2.75) | 0.019 |  |  | 0.017 |
 HGB level, × g/L (Mean, SD) | 106.38(20.91) | 123.19(19.13) | 0.839 | 125.00(25.00) | 122.50(17.75) | 0.031 |
 Blood glucose, × mmol/L (Mean, SD) | 6.81(2.36) | 6.95(2.71) | 0.058 | 38.00(5.00) | 38.00(6.00) | 0.087 |
 BUN, × mmol/L (Mean, SD) | 8.12(4.15) | 7.21(4.99) | 0.198 |  |  | 0.008 |
 Cr, × umol/L (Mean, SD) | 74.23(48.61) | 71.88(67.80) | 0.040 | 125.00(25.00) | 122.50(17.75) | 0.033 |
 D-Dimer, × mg/L (Mean, SD) | 4.85(4.60) | 4.89(5.14) | 0.009 | 2.98(4.43) | 4.24(7.45) | 0.056 |
Common complication | ||||||
 DVT (n, %) | 41(16.0) | 123(12.1) | 0.112 | 35(15.4) | 10(17.5) | 0.059 |
 UTI (n, %) | 88(34.4) | 206(20.3) | 0.319 | 73(32.0) | 78(34.2) | 0.047 |
 Pneumonia (n, %) | 36(14.1) | 79(7.8) | 0.202 | 28(12.3) | 29(12.7) | 0.013 |