Table 2.
Combined Results for the 3 Linear Multivariable Models a
| 1-Year KOOS-Pain (n = 791) | KOOS-Pain 10-Point Improvement (n = 791) | 1-Year PASS (n = 775) | ||||
|---|---|---|---|---|---|---|
| Factor | OR (95% CI) | P | OR (95% CI) | P | OR (95% CI) | P |
| Age, IQR increase, y | 1.11 (0.94-1.31) | .23 | 1.11 (0.86-1.42) | .42 | 1.13 (0.91-1.41) | .280 |
| Sex, female (vs male) | 0.81 (0.63-1.05) | .106 | 0.9 (0.61-1.34) | .604 | 0.98 (0.7-1.36) | .888 |
| Race | ||||||
| Black (vs White) | 0.88 (0.56-1.38) | .574 | 0.77 (0.41-1.46) | .428 | 0.79 (0.44-1.42) | .434 |
| Other (vs White) | 0.71 (0.35-1.43) | .336 | 1.01 (0.34-2.96) | .992 | 0.6 (0.24-1.49) | .274 |
| BMI, IQR increase, kg/m2 | 0.85 (0.72-1) | .052 | 0.76 (0.6-0.96) b | .022 | 0.84 (0.68-1.03) | .094 |
| Education, IQR increase, y | 1 (0.83-1.2) | .98 | 1.25 (0.93-1.68) | .14 | 0.84 (0.65-1.07) | .162 |
| Smoking | ||||||
| Quit ≥6 mo (vs never) | 1.06 (0.79-1.42) | .714 | 0.97 (0.62-1.53) | .906 | 0.88 (0.6-1.28) | .496 |
| Quit <6 mo (vs never) | 1.33 (0.44-3.98) | .614 | 3 (0.36-25.21) | .31 | 0.53 (0.14-1.97) | .342 |
| Current (vs never) | 0.66 (0.42-1.03) | .068 | 0.64 (0.35-1.19) | .16 | 0.79 (0.46-1.36) | .390 |
| T0 VR12-MCS, IQR increase | 1.55 (1.27-1.9) | <.001 | 1.5 (1.12-2.01) | .006 | 1.15 (0.89-1.48) | .288 |
| T0 KOOS-Pain, IQR increase | 2.1 (1.77-2.48) | <.001 | 0.57 (0.44-0.73) | <.001 | 1.42 (1.15-1.76) | .002 |
| Medial cartilage | ||||||
| Unipolar (vs normal) | 0.75 (0.55-1.03) | .076 | 0.99 (0.6-1.63) | .958 | 0.92 (0.61-1.39) | .682 |
| Bipolar (vs normal) | 0.53 (0.35-0.81) c | .004 | 0.58 (0.31-1.08) | .084 | 0.51 (0.3-0.87) | .014 |
| Lateral cartilage | ||||||
| Unipolar (vs normal) | 0.81 (0.54-1.23) | .32 | 0.73 (0.4-1.32) | .296 | 0.62 (0.37-1.03) | .068 |
| Bipolar (vs normal) | 0.82 (0.44-1.5) | .516 | 0.94 (0.37-2.37) | .896 | 1.3 (0.55-3.09) | .548 |
| Patellofemoral cartilage | ||||||
| Unipolar (vs normal) | 1.22 (0.89-1.68) | .224 | 1.12 (0.68-1.84) | .66 | 1.08 (0.71-1.63) | .728 |
| Bipolar (vs normal) | 1.36 (0.89-2.06) | .152 | 1.37 (0.71-2.62) | .344 | 1.51 (0.87-2.62) | .144 |
| Tear type | ||||||
| Lateral (vs medial) | 0.76 (0.52-1.13) | .182 | 0.72 (0.41-1.27) | .26 | 0.94 (0.56-1.57) | .808 |
| Both (vs medial) | 0.92 (0.65-1.31) | .656 | 0.97 (0.56-1.68) | .916 | 0.96 (0.6-1.52) | .854 |
| Effusion, yes (vs no) | 1.34 (0.91-1.96) | .136 | 1.52 (0.79-2.92) | .206 | 1.31 (0.79-2.17) | .304 |
| Synovitis, yes (vs no) | 0.89 (0.61-1.31) | .566 | 0.87 (0.48-1.55) | .63 | 1.36 (0.82-2.26) | .234 |
| Chondroplasty | ||||||
| Grade 1 (vs none) | 0.91 (0.67-1.24) | .556 | 0.99 (0.61-1.59) | .962 | 0.89 (0.6-1.32) | .548 |
| Grade 2 (vs none) | 0.82 (0.56-1.19) | .288 | 0.7 (0.4-1.22) | .208 | 0.78 (0.48-1.26) | .302 |
| Grade 3 (vs none) | 1.15 (0.59-2.26) | .682 | 2.09 (0.61-7.17) | .244 | 2.19 (0.81-5.89) | .120 |
| ADI, IQR increase | 0.77 (0.62-0.95) | .014 | 0.71 (0.52-0.99) | .042 | 0.96 (0.72-1.26) | .748 |
Bold values represent significant associations (P < .05). ADI, Area Deprivation Index; BMI, body mass index; IQR, interquartile range; KOOS, Knee injury and Osteoarthritis Outcome Score; OR, odds ratio; PASS, Patient Acceptable Symptom State; T0, baseline; VR12-MCS, Veterans RAND 12-Item Health Survey–Mental Component Score.
The OR for the BMI was 0.76 kg/m2 in the KOOS-Pain 10-point improvement model. Thus, the odds of getting a 10-point improvement in those with a third quartile BMI was 24% lower than those with a first quartile BMI after controlling for other variables in the model.
The OR for bipolar medial cartilage was 0.53 in the 1-year KOOS-Pain linear model. Thus, the odds of getting a 1-year KOOS-Pain of at least x in those with bipolar medial cartilage was 47% lower than those with normal medial cartilage after controlling for other variables in the model. The value of x is irrelevant since this is a proportional odds model.