Table 3.
Multivariable linear regression analysis of factors associated with the KOOS JR at baseline, accounting for factor 1 pain coping and factor 2 mood
| Variable | Regression coefficient (95% CI) | Standard error | Partial R2 | p value |
| Factor 1: Pain coping | -4.3 (-5.4 to -3.2) | 0.56 | 0.076 | < 0.001 |
| Factor 2: Mood | -0.31 (-1.4 to 0.74) | 0.53 | 0.00048 | 0.56 |
| Kellgren-Lawrence grade | -0.87 (-1.6 to -0.11) | 0.38 | 0.0073 | 0.02 |
| Age | -0.0099 (-0.14 to 0.13) | 0.069 | 0.000030 | 0.89 |
| BMI | -0.30 (-0.42 to -0.19) | 0.059 | 0.037 | < 0.001 |
| Gender | ||||
| Women | Reference value | |||
| Men | 2.3 (0.21 to 4.3) | 1.0 | 0.0067 | 0.03 |
| Race | ||||
| White | Reference value | |||
| Other | -3.3 (-5.3 to -1.3) | 1.0 | 0.015 | 0.001 |
| Marital status | ||||
| Married or partner | Reference value | |||
| Divorced or separated | 0.66 (-2.1 to 3.5) | 1.4 | 0.00031 | 0.64 |
| Single | 3.4 (0.86 to 6.0) | 1.3 | 0.0097 | 0.009 |
| Widowed | 2.4 (-0.71 to 5.6) | 1.6 | 0.0033 | 0.13 |
| Employment status | ||||
| Employed | Reference value | |||
| Unemployed | -0.51 (-4.2 to 3.2) | 1.9 | 0.00011 | 0.79 |
| Retired | 1.1 (-1.6 to 3.8) | 1.4 | 0.00095 | 0.42 |
| Disabled | -2.9 (-7.0 to 1.2) | 2.1 | 0.0028 | 0.16 |
| Insurance type | ||||
| Commercial or employer | Reference value | |||
| Medicare | -3.1 (-5.7 to -0.39) | 1.4 | 0.0072 | 0.03 |
| Safety-net | -5.0 (-11 to 0.47) | 2.8 | 0.0046 | 0.07 |
| Medicaid | 3.1 (-2.7 to 8.8) | 2.9 | 0.0016 | 0.29 |
| Other | -2.8 (-10 to 4.5) | 3.7 | 0.00083 | 0.45 |
| Primary total joint replacement | ||||
| No | Reference value | |||
| Yes | -3.6 (-6.2 to -0.97) | 1.3 | 0.010 | 0.007 |
Adjusted R2 = 0.25; that is, this combination of variables explains 25% of the variance in KOOS JR at baseline. KOOS JR = Knee Disability and Osteoarthritis Outcome Score for Joint Replacement.