Table 5.
Multivariate logistic model for whether separate SES variables individually predict clinically significant PCS improvement (5 points yes/no, 63% clinically significant improvement) among primary TKAs (n=1,723)
| With SES Variables | No SES Variables | |||||
|---|---|---|---|---|---|---|
| Variable | OR | 95% CI | P-Value | OR | 95% CI | P-Value |
| Race (ref = Non-Hispanic White) | ||||||
| Other | 0.78 | 0.34–1.79 | 0.556 | -- | -- | -- |
| Living Alone (ref = No) | ||||||
| Yes | 1.18 | 0.69–2.03 | 0.548 | -- | -- | -- |
| Missing | 1.36 | 0.66–2.77 | 0.405 | -- | -- | -- |
| Education (ref = Postgrad) | ||||||
| College | 0.89 | 0.49–1.62 | 0.698 | -- | -- | -- |
| Some College | 1.06 | 0.59–1.90 | 0.852 | -- | -- | -- |
| High School or Less | 1.43 | 0.76–2.67 | 0.266 | -- | -- | -- |
| Missing | 2.26 | 0.83–6.16 | 0.111 | -- | -- | -- |
| Employment (ref = Working/Student) | ||||||
| Retired, Not for Health | 0.67 | 0.39–1.14 | 0.136 | -- | -- | -- |
| Not Working | 0.55 | 0.32–0.95 | 0.031 | -- | -- | -- |
| Missing | 0.55 | 0.22–1.40 | 0.208 | -- | -- | -- |
| Household Annual Income (ref = $75,000+) | ||||||
| $50–75,000 | 0.74 | 0.33–1.67 | 0.469 | -- | -- | -- |
| $35–50,000 | 1.83 | 0.72–4.63 | 0.203 | -- | -- | -- |
| <$35,000 | 1.32 | 0.58–3.00 | 0.506 | -- | -- | -- |
| Refused to Answer | 0.98 | 0.49–1.98 | 0.961 | -- | -- | -- |
| Missing | 0.53 | 0.24–1.16 | 0.110 | -- | -- | -- |
| Surgeon (ref = Surgeon 1) | ||||||
| Surgeon 2 | 0.94 | 0.62–1.42 | 0.755 | 0.91 | 0.61–1.36 | 0.649 |
| Surgeon 3 * | -- | -- | -- | -- | -- | -- |
| Surgeon 4 | 0.68 | 0.24–1.89 | 0.457 | 0.66 | 0.23–1.86 | 0.431 |
| Surgeon 5 | 0.89 | 0.61–1.28 | 0.530 | 0.89 | 0.62–1.27 | 0.512 |
| Surgeon 6 | 0.92 | 0.65–1.31 | 0.645 | 0.91 | 0.64–1.28 | 0.574 |
| Surgeon 7 | 0.65 | 0.34–1.26 | 0.202 | 0.62 | 0.32–1.19 | 0.149 |
| Surgeon 8 | 1.49 | 0.64–3.48 | 0.353 | 1.21 | 0.53–2.75 | 0.646 |
| Surgeon 9 | 0.92 | 0.60–1.41 | 0.695 | 0.89 | 0.58–1.35 | 0.574 |
| Age Group (ref = <55) | ||||||
| 55–59 | 0.82 | 0.52–1.28 | 0.375 | 0.80 | 0.51–1.24 | 0.314 |
| 60–64 | 1.24 | 0.81–1.91 | 0.315 | 1.18 | 0.78–1.79 | 0.438 |
| 65–69 | 1.00 | 0.65–1.55 | 0.999 | 0.93 | 0.61–1.42 | 0.747 |
| 70–74 | 0.94 | 0.58–1.53 | 0.808 | 0.88 | 0.55–1.40 | 0.586 |
| 75–79 | 0.79 | 0.45–1.37 | 0.398 | 0.72 | 0.42–1.22 | 0.221 |
| 80+ | 0.63 | 0.36–1.10 | 0.105 | 0.61 | 0.35–1.06 | 0.080 |
| Sex (ref = Male) | ||||||
| Female | 1.07 | 0.83–1.37 | 0.609 | 1.05 | 0.82–1.34 | 0.702 |
| Preoperative Alcohol Use (ref = No) | ||||||
| Yes | 1.06 | 0.82–1.37 | 0.663 | 1.01 | 0.79–1.31 | 0.912 |
| Preoperative Tobacco Use (ref = Never) | ||||||
| Quit | 0.83 | 0.64–1.07 | 0.154 | 0.83 | 0.64–1.07 | 0.151 |
| Yes | 0.59 | 0.37–0.96 | 0.033 | 0.58 | 0.36–0.92 | 0.020 |
| Charlson Score (ref = 0) | ||||||
| 1 | 0.71 | 0.53–0.95 | 0.023 | 0.71 | 0.53–0.95 | 0.019 |
| 2+ | 0.85 | 0.62–1.16 | 0.306 | 0.83 | 0.61–1.13 | 0.235 |
| VR-12 PCS Preoperative (ref = 50+) | ||||||
| 40–49.99 | 6.31 | 3.22–12.36 | <0.001 | 6.23 | 3.22–12.07 | <0.001 |
| 30–39.99 | 25.69 | 13.25–49.81 | <0.001 | 24.80 | 12.89–47.74 | <0.001 |
| 20–29.99 | 38.79 | 19.95–75.39 | <0.001 | 37.25 | 19.33–71.79 | <0.001 |
| <20 | 57.48 | 26.97–122.48 | <0.001 | 54.09 | 25.66–114.05 | <0.001 |
| VR-12 MCS Preoperative (ref = 60+) | ||||||
| 50–59.99 | 0.99 | 0.73–1.34 | 0.948 | 0.97 | 0.72–1.31 | 0.836 |
| 40–49.99 | 0.51 | 0.35–0.73 | <0.001 | 0.50 | 0.35–0.70 | <0.001 |
| 30–39.99 | 0.42 | 0.27–0.65 | <0.001 | 0.42 | 0.28–0.65 | <0.001 |
| <30 | 0.35 | 0.20–0.59 | <0.001 | 0.35 | 0.21–0.60 | <0.001 |
| VR-12 PCS Post-Op Time Period (ref = 0 – 45 Days) | ||||||
| 46 – 299 Days | 4.51 | 3.10–6.55 | <0.001 | 4.43 | 3.06–6.39 | <0.001 |
| 300 – 420 Days | 7.15 | 4.73–10.79 | <0.001 | 6.86 | 4.55–10.32 | <0.001 |
| 421 + Days | 7.09 | 4.34–11.60 | <0.001 | 6.90 | 4.23–11.27 | <0.001 |
| Year (ref = 2011) | ||||||
| 2012 | 0.96 | 0.60–1.53 | 0.863 | 0.96 | 0.61–1.51 | 0.850 |
| 2013 | 1.00 | 0.62–1.60 | 0.989 | 1.00 | 0.64–1.58 | 0.983 |
| 2014 | 0.68 | 0.40–1.14 | 0.143 | 0.69 | 0.41–1.14 | 0.145 |
| 2015 | 0.86 | 0.46–1.61 | 0.643 | 0.88 | 0.48–1.61 | 0.678 |
| Bilateral TKA (ref = No) | ||||||
| Yes | 1.77 | 1.30–2.42 | <0.001 | 1.75 | 1.29–2.37 | <0.001 |
| BMI Preoperative (ref = Normal, <25) | ||||||
| Overweight, 25–29.99 | 0.96 | 0.65–1.42 | 0.854 | 0.92 | 0.63–1.36 | 0.689 |
| Obese, 30–34.99 | 0.70 | 0.46–1.06 | 0.092 | 0.66 | 0.44–1.01 | 0.053 |
| Severe Obese, 35–39.99 | 0.76 | 0.48–1.21 | 0.252 | 0.73 | 0.46–1.15 | 0.171 |
| Morbid Obese, 40+ | 0.71 | 0.44–1.14 | 0.155 | 0.68 | 0.42–1.08 | 0.102 |
| 10-fold cross-validation AUC | ||||||
| 0.81 | 0.79–0.83 | 0.80 | 0.78–0.82 | |||
Clustered on 1,723 patients and using robust standard errors to account for observational data
Surgeon 3 performed 2 surgeries with pre-operative and post-operative VR-12 scores and was excluded from analysis.
Among patients that completed VR-12s at multiple post-operative time periods, the order of priority for this model was 300 – 420 days, more than 421 days, 46 – 299 days, and 0 – 45 days post-operative.