Multivariable Models in Prediction of Incident Symptomatic Knee Osteoarthritis (OA) and Internal Validation (Calibration and Discrimination) of the Risk Prediction Models
| Selected Predictors | Basic Model | Backward Model | ||
|---|---|---|---|---|
| OR (95% CI) | P Value | OR (95% CI) | P Value | |
| Age (years) | 1.07 (0.98–1.17) | .15 | 1.14 (1.02–1.28) | .02 |
| BMI (kg/m2) | 1.12 (1.04–1.20) | <.01 | 1.16 (1.06–1.26) | .001 |
| Mild knee symptoms* | 1.73 (0.85–3.49) | .13 | ||
| Knee problems while climbing stairs† | 2.08 (1.03–4.23) | .04 | ||
| Morning stiffness‡ | 2.46 (0.97–6.25) | .06 | ||
| Postmenopausal status | 0.54 (0.26–1.12) | .10 | ||
| Physically demanding work§ | 2.38 (0.83–6.83) | .11 | ||
| AUC of the model | 0.63 (0.54–0.71) | 0.72 (0.64–0.80) | ||
| Calibration: Hosmer-Lemeshow P value | .96 | .20 | ||
| Variance explained (Nagelkerke), % | 6.5 | 21.9 | ||
AUC, area under the curve of the receiver operating characteristic; BMI, body mass index; CI, confidential interval; OR, odds ratio.
Bold indicates P < .05.
↵* Pain in or around the knee within the last 12 months.
↵† Defined with the Knee Injury and Osteoarthritis Outcome Score (KOOS) on physical functioning.
↵‡ Defined with the KOOS on stiffness.
↵§ Defined as doing intense work (regularly lifting heavy objects at work).