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Table 2 Four models and pooled OR (odds ratios) for diagnosing early stage OA

From: Diagnosis of early stage knee osteoarthritis based on early clinical course: data from the CHECK cohort

  Model 1 Model 2 Model 3 Model 4
  Pooled OR (95% CI) Pooled OR (95% CI) Pooled OR (95% CI) Pooled OR (95% CI)
Baseline factors
BMI    1.12 (1.08–1.17) 1.10 (1.06–1.15)
Gender (female)    1.60 (1.10–2.33) 1.67 (1.14–2.46)
WOMAC function descending     
 Positive vs. negativea    1.94 (1.35–2.78) 1.85 (1.29–2.64)
WOMAC function rising
 Positive vs. negativea    1.56 (1.10–2.21)  
WOMAC stiffness
 Positive vs. negativea    1.56 (1.13–2.16) 1.94 (1.41–2.67)
Joint effusion     
 Positive vs. negative b    4.36 (2.35–8.12)  
Medial TF JSN
 Positive vs. negativeb     3.70 (2.07–6.63)
Course factorsc
Joint line tenderness
 Positive at either time point 1.58 (1.16–2.17) 1.59 (1.15–2.19) 1.57 (1.13–2.19) 1.64 (1.17–2.31)
 Positive at both time points 2.28 (1.58–3.29) 2.20 (1.51–3.22) 1.83 (1.24–2.70) 1.95 (1.31–2.91)
Joint effusion
 Positive at either time point 3.28 (2.07–5.20) 2.98 (1.84–4.81)   3.00 (1.82–4.95)
Restricted/painful flexion
 Positive at either time point 1.49 (1.09–2.04) 1.36 (0.99–1.88)   
 Positive at both time points 2.54 (1.51–4.27) 2.35 (1.38–3.99)   
Restricted/painful extensiond
 Positive at either time point 0.74 (0.55–0.99) 0.69 (0.51–0.94) 0.70 (0.51–0.96) 0.66 (0.48–0.91)
PF joint crepitus
 Positive at either time point 1.44 (1.03–2.01) 1.45 (1.03–2.03)   
 Positive at both time points 1.87 (1.34–2.62) 1.87 (1.32–2.64) 1.85 (1.34–2.55) 1.68 (1.21–2.34)
WOMAC function descendinge
 Increase 1.66 (1.19–2.32) 1.81 (1.29–2.55) 2.07 (1.45–2.96) 2.30 (1.59–3.32)
Medial TF osteophyte
 Increase   1.68 (1.15–2.46)   1.59 (1.06–2.40)
Lateral TF osteophyte
 Increase   2.08 (1.46–2.95)   1.84 (1.26–2.70)
PF JSN
 Increase   2.59 (1.49–4.51)   2.45 (1.37–4.39)
Pooled model intercept − 1.16 − 1.43 − 4.81 − 4.76
  1. BMI, body mass index; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index; TF, tibia femoral; JSN, joint space narrowing; PF, patellofemoral joint
  2. Model 1, included clinical course factors only; model 2, included clinical and radiographic course factors; model 3, clinical course factors + clinical baseline factors; model 4, clinical and radiographic course factors + clinical and radiographic baseline factors
  3. aAll the WOMAC items have 5 grades (0 to 4). Patient graded at 2 or more were treated as positive presentation at baseline, negative knees were treated as reference
  4. bRadiographic items were graded according to Kellgren & Lawrence criteria, and grade 2 or more was treated as positive; negative knees were treated as reference
  5. cCategory of negative at both time points or stable was treated as reference. Few patients (1%) presented joint effusion at both time points; we incorporated these patients into the category of positive at either time point before statistical analysis. Few patients (1–3%) presented decreased severity in radiographic items, and we incorporated them into the stable category before statistical analysis
  6. dThe category of positive at both time points was not significant and incorporated into the reference category
  7. eThe decrease category was not significant and incorporated into the reference category