Table 5.
Multivariable-adjusted association of income with improvement in knee function after primary TKA
| 2 years | 5 years | |||||||
|---|---|---|---|---|---|---|---|---|
| Better | Much better | Better | Much better | |||||
| Odds ratio (95% CI) | P value | Odds ratio (95% CI) | P value | Odds ratio (95% CI) | P value | Odds ratio (95% CI) | P value | |
| ≤ US$35, 000 | 1.9 (1.0 to 3.6) | 0.06 | 1.4 (0.8 to 2.5) | 0.26 | 1.7 (0.8 to 3.4) | 0.16 | 1.5 (0.9 to 2.8) | 0.15 |
| > US$35, 000 to US$45, 000 | 1.4 (0.8 to 2.4) | 0.25 | 1.4 (0.9 to 2.3) | 0.14 | 1.2 (0.6 to 2.2) | 0.64 | 1.0 (0.6 to 1.7) | 0.93 |
| > US$45, 000 (ref) | 1.00 | 1.00 | 1.00 | 1.00 | ||||
Data additionally adjusted for the following variables at baseline: age category, gender, body mas index (BMI) category, Deyo-Charlson index, American Society of Anesthesiologists (ASA) class, distance, operative diagnosis, implant fixation, preoperative pain (for pain models) and preoperative functional limitation (for functional limitation models). Significant variables in each model included the following: (1) 2-year model: ASA class III/IV (P < 0.01) with lower odds for much better status and distance > 100 to 500 miles with lower odds for much better status (P = 0.03); and preoperative activity limitation (P < 0.001); (2) 5-year model: ASA class III/IV (P < 0.01) with lower odds for much better status.