Table 2.
Comparison between patients included and excluded from the current analysis
| Variable | Excluded n = 113 | Included n = 159 | Total n = 272 | p value |
| Age, mean ± SD | 56 ± 17 | 58 ± 14 | 57 ± 15 | 0.40a |
| Sex, % (n) | 0.04b | |||
| Male | 40 (45) | 28 (44) | 33 (89) | |
| Female | 60 (68) | 72 (115) | 67 (183) | |
| Race, % (n) | 0.15c | |||
| White or Caucasian | 84 (95) | 75 (120) | 79 (215) | |
| East Asian | 15 (17) | 21 (33) | 18 (50) | |
| Other | 1 (1) | 4 (6) | 3 (7) | |
| Patients with previous spine surgeries, % (n) | 62 (70) | 62 (99) | 62 (169) | 0.96b |
| GAP category, % (n) | 0.07b | |||
| Proportioned | 12 (9)d | 5 (8) | 7 (17)d | |
| Moderately disproportioned | 41 (31)d | 35 (55) | 37 (86)d | |
| Severely disproportioned | 47 (36)d | 60 (96) | 56 (132)d |
a
t test.
b
Chi-square test.
c
Fisher's exact test.
d
For patients excluded from the current analysis, information sufficient to calculate the GAP score was only available in 76 patients.