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Table 1 Baseline characteristics at inclusion and predictors of knee replacement, univariate and multivariate analyses

From: Risk factors for joint replacement in knee osteoarthritis; a 15-year follow-up study

  Total Knee replacement Unadjusted Adjusteda
Variable (n = 100) Yes (n = 66) No (n = 34) OR (95% CI) p value OR (95% CI) p value
Female, % (no.) 64% (64) 68% (45) 56% (19) 1.0 (0.9 – 1.0) 0.52   
Age (years), mean (SD) 62.0 (10.4) 61.3 (10.0) 63.4 (10.9) 1.0 (0.9 – 1.0) 0.34   
BMI grade, mean (SD) 2.2 (0.9) 2.2 (0.9) 2.0 (0.9) 1.2 (0.8 – 2.0) 0.41   
WOMAC, mean (SD):
- Pain 184 (89) 196 (95) 161 (71) 1.0 (1.0 – 1.0) 0.07   
- Stiffness 81 (45) 87(46) 67 (40) 1.3 (1.01 – 1.6)c 0.04 1.3 (1.01 – 1.7)c 0.04
- Function 657 (319) 692 (332) 588 (281) 1.0 (1.0 – 1.0) 0.13   
- Total 922 (427) 976 (446) 817 (366) 1.0 (1.0 – 1.0) 0.08   
Hyalgan %, (no.) 48% (48) 50% (33) 44% (15) 1.3 (0.6 – 2.9) 0.58   
JSN grade, mean (SD) 1.7 (1.0) 2.0 (0.9) 1.0 (0.8) 3.6 (2.1 - 6.2) <0.001 5.0 (2.6 - 9.9) <0.001
Radiological sum score, mean (SD) 5.0 (2.6) 5.8 (2.3) 3.4 (2.5) 1.5 (1.3 - 1.9) <0.001 1.7 (1.3 - 2.1) <0.001
BML grade, mean (SD)b, d 2.1 (1.4) 2.4 (1.5) 1.4 (0.9) 2.1 (1.2 – 3.7) 0.006 2.3 (1.3 – 4.0) 0.005
Synovitis grade, mean (SD)b, e 2.6 (1.0) 2.9 (0.9) 2.0 (1.1) 2.7 (1.5 – 4.7) 0.001 2.8 (1.5 – 5.2) 0.001
Effusion grade, mean (SD)b, f 2.4 (1.5) 2.7 (1.6) 1.7 (1.1) 1.9 (1.2 – 3.0) 0.005 1.9 (1.2 – 3.1) 0.006
  1. OR odds ratio, CI confidence interval, No. number, SD standard deviation, BMI body mass index, WOMAC Western Ontario and McMaster Universities OA index, JSN joint space narrowing, BML bone marrow lesion
  2. aAdjusted for sex, age and BMI; b Based on 83 participants with MRI scans and tibiofemoral osteoarthritis; c Logistic regression performed after ordering data into a ten point ordinal scale (Grade 1 = 0 – 10, grade 2 = 11 – 20 etc.); d Ordered into a ten point ordinal scale (Grade 1 = 0 - 10% BML, grade 2 = >10 - 20% BML etc.); eOrdered into a five point ordinal scale (Grade 1 = 0 - <5; grade 2 = 5 - <10 etc.); f Ordered into an eight point ordinal scale (Grade 1 = 0 - < 5; grade 2 = 5 - <10 etc.) (maximum effusion score = 38)