Table 1.
Patient Characteristics Between OPLL and CSM Before and After Matching.
| Before Propensity Score Matching | After Propensity Score Matching | |||||
|---|---|---|---|---|---|---|
| OPLL (N = 7485) | CSM (N = 15,229) | P Value | OPLL (N = 7169) | CSM (N = 7169) | P Value | |
| Age (years) | 65.1 ± 10.9 | 69.3 ± 11.2 | <.001*** | 65.6 ± 10.4 | 65.3 ± 12.0 | .08 |
| Sex | .50 | .91 | ||||
| Male | 5221 (69.8%) | 10,689 (70.2%) | 5000 (69.7%) | 4994 (69.7%) | ||
| Female | 2264 (30.2%) | 4540 (29.8%) | 2169 (30.3%) | 2175 (30.3%) | ||
| BMI (kg/m 2 ) | 25.3 ± 4.4 | 23.7 ± 4.2 | <.001*** | 24.9 ± 3.9 | 24.8 ± 4.8 | .62 |
| Smoking | <.001*** | .41 | ||||
| Yes | 3772 (50.4%) | 6990 (45.9%) | 3588 (50.0%) | 3637 (50.7%) | ||
| No | 3713 (49.6%) | 8239 (54.1%) | 3581 (50.0%) | 3532 (49.3%) | ||
| Admission type | .53 | .31 | ||||
| Scheduled | 6873 (91.8%) | 14,025 (92.1%) | 6586 (91.9%) | 6552 (91.4%) | ||
| Unscheduled | 611 (8.2%) | 1199 (7.9%) | 583 (8.1%) | 617 (8.6%) | ||
| Unknown | 1 (.01%) | 5 (.03%) | 0 (0%) | 0 (0%) | ||
| Emergency transport | .62 | .87 | ||||
| Yes | 178 (2.4%) | 378 (2.5%) | 171 (2.4%) | 168 (2.3%) | ||
| No | 7306 (97.6%) | 14,846 (97.5%) | 6998 (97.6%) | 7001 (97.7%) | ||
| Unknown | 1 (.01%) | 5 (.03%) | 0 (0%) | 0 (0%) | ||
| Hospital type | .71 | .47 | ||||
| Academic | 1350 (18.0%) | 2778 (18.2%) | 1279 (17.8%) | 1246 (17.4%) | ||
| Non-academic | 6135 (82.0%) | 12,451 (81.8%) | 5890 (82.2%) | 5923 (82.6%) | ||
| ADL score for admission (points) | 17.2 ± 5.3 | 17.1 ± 5.3 | .64 | 17.2 ± 5.3 | 17.1 ± 5.3 | .59 |
| Preoperative comorbidities | ||||||
| Diabetes mellitus | 2070 (27.7%) | 3746 (24.6%) | <.001*** | 1949 (27.2%) | 1964 (27.4%) | .78 |
| Cardiovascular disease | 413 (5.5%) | 1095 (7.2%) | <.001*** | 403 (5.6%) | 385 (5.4%) | .51 |
| Cerebrovascular disease | 276 (3.7%) | 624 (4.1%) | .14 | 266 (3.7%) | 289 (4.0%) | .32 |
| Respiratory disease | 54 (.7%) | 174 (1.1%) | .003** | 51 (.7%) | 43 (.6%) | .41 |
| Renal failure | 149 (2.0%) | 680 (4.5%) | <.001*** | 148 (2.1%) | 134 (1.9%) | .40 |
| Hepatic failure | 235 (3.1%) | 555 (3.6%) | .05 | 231 (3.2%) | 213 (3.0%) | .39 |
| Gastric ulcer and hemorrhage | 228 (3.1%) | 514 (3.4%) | .19 | 225 (3.1%) | 219 (3.1%) | .77 |
| Malignancy | 95 (1.3%) | 245 (1.6%) | .048* | 95 (1.3%) | 90 (1.3%) | .71 |
| Rheumatoid arthritis | 41 (.6%) | 150 (1.0%) | .001** | 40 (.6%) | 57 (.8%) | .08 |
| Osteoporosis | 102 (1.4%) | 488 (3.2%) | <.001*** | 94 (1.4%) | 88 (1.2%) | .51 |
Data was presented as n (%) or mean ± SD. Significant values are given as follows. *P < .05, **P < .01, ***P < .001.
Abbreviation: OPLL, ossification of posterior longitudinal ligament; CSM, cervical spondylotic myelopathy; SD, standard deviation; BMI, body mass index; ADL, activities of daily living.