Table 2. Comparison of Primary and Secondary Outcomes Between Propensity-score Matched Groups.
| Outcome | No. (%) of patients | Absolute risk difference (95% CI), %b |
Hazard ratio (95% CI)c |
|
|---|---|---|---|---|
| Anterior approach (n = 2993) |
Lateral or posterior approach (n = 2993)a |
|||
| Primary outcome | ||||
| Major surgical complication, within 1 y | 61 (2.0) | 29 (1.0) | 1.07 (0.46 to 1.69) | 2.07 (1.48 to 2.88) |
| Secondary outcomes | ||||
| Categorical | ||||
| Surgical complications ≤1 y | ||||
| Deep infection | 36 (1.2) | 11 (0.4) | 0.84 (0.39 to 1.29) | 3.27 (1.91 to 5.62) |
| Dislocation | 21 (0.7) | 8 (0.3) | 0.44 (0.08 to 0.79) | 2.63 (1.40 to 4.93) |
| Revision | 36 (1.2) | 20 (0.7) | 0.54 (0.05 to 1.01) | 1.75 (1.17 to 2.62) |
| ED ≤30 d | 449 (15.0) | 433 (14.5) | 0.54 (−1.26 to 2.33) | |
| Readmission ≤30 d | 7 (0.2) | 10 (0.3) | −0.10 (−0.37 to 0.17) | |
| Continuous | Median (IQR) within-pair differencesd | |||
| Surgery time, median (IQR), min | 108 (94 to 130) | 99 (84 to 118) | 11 (−13 to 36) | |
| LOS, median (IQR), d | 2 (1 to 3) | 2 (2 to 3) | −1 (−2 to 0) | |
Abbreviations: ED, emergency department; IQR, interquartile range; LOS length of stay.
a
Lateral, 2326 patients; posterior, 667 patients.
b
Expressed as a percentage (with 95% CIs) calculated using generalized estimating equations.
c
Hazard ratios for occurrence of each surgical complication were also calculated using a Cox proportional hazards model with robust variance estimation that accounted for pair matching. The reference group was use of either the lateral or posterior approach.
d
Median and IQRs for within-pair differences (anterior vs lateral or posterior) after matching for surgical duration and acute length of stay were calculated.