Demographics and baseline characteristics before and after propensity-score matching
| Preoperative characteristics | Before matching | After matching | ||||||
| Total (n=40 527) | Spinal (n=9847) | General (n=30 680) | P value | Total (n=14 716) | Spinal (n=7358) | General (n=7358) | P value | |
| Age (years), mean (SD) | 80.25 (9.73) | 81.79 (8.93) | 79.76 (9.93) | <0.001 | 81.32 (9.16) | 81.25 (9.14) | 81.40 (9.17) | 0.30 |
| Sex, female (n) | 68.84% (27 897) | 71.23% (7014) | 68.07% (20 883) | <0.001 | 71.15% (10 471) | 71.23% (5241) | 71.08% (5230) | 0.84 |
| BMI (kg/m2), mean (SD) | 25.23 (5.84) | 24.53 (5.39) | 25.41 (5.95) | <0.001 | 24.59 (5.39) | 24.58 (5.39) | 24.59 (5.38) | 0.90 |
| ASA class | <0.001 | 0.99 | ||||||
| I | 0.60% (242) | 0.83% (82) | 0.52% (160) | 0.74% (109) | 0.75% (55) | 0.73% (54) | ||
| II | 15.23% (6173) | 16.72% (1646) | 14.76% (4527) | 18.06% (2657) | 17.97% (1322) | 18.14% (1335) | ||
| III | 62.43% (25 300) | 59.45% (5854) | 63.38% (19 446) | 60.21% (8861) | 60.06% (4419) | 60.37% (4442) | ||
| IV | 21.42% (8679) | 22.47% (2213) | 21.08% (6466) | 20.66% (3041) | 20.90% (1538) | 20.43% (1503) | ||
| V | 0.18% (71) | 0.19% (19) | 0.17% (52) | 0.20% (29) | 0.19% (14) | 0.20% (15) | ||
| None assigned | 0.15% (62) | 0.34% (33) | 0.09% (29) | 0.13% (19) | 0.14% (10) | 0.12% (9) | ||
| Diabetes (n) | 18.56% (7520) | 16.12% (1587) | 19.34% (5933) | <0.001 | 16.06% (2364) | 16.53% (1216) | 15.60% (1148) | 0.13 |
| Smoker (n) | 11.53% (4673) | 10.40% (1024) | 11.89% (3649) | <0.001 | 10.78% (1586) | 10.99% (809) | 10.56% (777) | 0.39 |
| COPD (n) | 10.50% (4256) | 10.82% (1065) | 10.40% (3191) | 0.24 | 11.35% (1670) | 11.44% (842) | 11.25% (828) | 0.72 |
| Congestive heart failure (n) | 3.71% (1505) | 3.21% (316) | 3.88% (1189) | 0.002 | 3.13% (460) | 3.19% (235) | 3.06% (225) | 0.64 |
| Hypertension (n) | 66.48% (26 944) | 62.67% (6171) | 67.71% (20 773) | <0.001 | 63.20% (9300) | 63.37% (4663) | 63.02% (4637) | 0.66 |
| Acute renal failure (n) | 0.58% (236) | 0.37% (36) | 0.65% (200) | 0.001 | 0.33% (48) | 0.31% (23) | 0.34% (25) | 0.77 |
| Current dialysis (n) | 1.93% (784) | 1.23% (121) | 2.16% (663) | <0.001 | 1.37% (201) | 1.30% (96) | 1.43% (105) | 0.52 |
| Disseminated cancer (n) | 3.32% (1347) | 2.72% (268) | 3.52% (1079) | <0.001 | 2.87% (423) | 2.83% (208) | 2.92% (215) | 0.73 |
| Open wound (with or without infection) (n) | 3.67% (1487) | 2.37% (233) | 4.09% (1254) | <0.001 | 2.36% (347) | 2.36% (174) | 2.35% (173) | 0.96 |
| Steroid use (n) | 5.63% (2283) | 4.94% (486) | 5.86% (1797) | <0.001 | 4.98% (733) | 5.07% (373) | 4.89% (360) | 0.62 |
| Bleeding disorder (n) | 17.10% (6929) | 8.00% (788) | 20.02% (6141) | <0.001 | 7.72% (1136) | 7.76% (571) | 7.68% (565) | 0.85 |
| Emergent case (n) | 31.69% (12 844) | 49.51% (4875) | 25.97% (7969) | <0.001 | 45.04% (6628) | 44.86% (3301) | 45.22% (3327) | 0.67 |
| Functional status | <0.001 | 0.96 | ||||||
| Independent (n) | 77.58% (31 441) | 77.66% (7647) | 77.56% (23 794) | 79.06% (11 635) | 79.23% (5830) | 78.89% (5805) | ||
| Partially dependent (n) | 18.86% (7644) | 18.23% (1795) | 19.06% (5849) | 17.85% (2627) | 17.72% (1304) | 17.98% (1323) | ||
| Totally dependent (n) | 3.02% (1223) | 3.32% (327) | 2.92% (896) | 2.57% (378) | 2.54% (187) | 2.60% (191) | ||
| Unknown (n) | 0.54% (219) | 0.79% (78) | 0.46% (141) | 0.52% (76) | 0.50% (37) | 0.53% (39) | ||
| Dementia (n) | 28.63% (11 603) | 30.80% (3033) | 27.93% (8570) | <0.001 | 28.50% (4194) | 28.20% (2075) | 28.80% (2119) | 0.42 |
| Preoperative delirium (n) | 12.81% (5146) | 12.56% (1228) | 12.88% (3918) | 0.40 | 11.20% (1648) | 11.13% (819) | 11.27% (829) | 0.79 |
| Fracture type | <0.001 | 0.028 | ||||||
| Femoral neck—undisplaced | 8.45% (3425) | 8.09% (797) | 8.57% (2628) | 8.52% (1254) | 7.95% (585) | 9.09% (669) | ||
| Femoral neck—displaced | 29.45% (11 937) | 31.78% (3129) | 28.71% (8808) | 31.50% (4636) | 32.36% (2381) | 30.65% (2255) | ||
| Intertrochanteric | 53.85% (21 823) | 52.14% (5134) | 54.40% (16 689) | 51.90% (7638) | 51.52% (3791) | 52.28% (3847) | ||
| Unknown | 2.04% (828) | 1.68% (165) | 2.16% (663) | 1.95% (287) | 1.86% (137) | 2.04% (150) | ||
| Subtrochanteric | 6.20% (2514) | 6.32% (622) | 6.17% (1892) | 6.12% (901) | 6.31% (464) | 5.94% (437) | ||
a: alpha level set at 0.05.
ASA, American Society of Anesthesiologists; BMI, body mass index; COPD, chronic obstructive pulmonary disease.