Table 1.
Adjusted means (95% confidence interval) for demographic and clinical pain characteristics of healthy controls and individuals with low and high symptomatic knee OA.
| Controls (N = 107) | Symptomatic Knee OA |
Analysis (Bold if significant) | ||
|---|---|---|---|---|
| Low (N = 113) | High (N = 96) | |||
| DEMOGRAPHIC CHARACTERISTICS | ||||
| Age (Years)† | 56.8 (55.3, 58.4) | 58.1 (56.7, 59.5) | 56.4 (54.8, 58.1) | F = 1.42, n.s., ηp2 = .01 |
| BMI (Weight/Height2)† | 28.7 (27.2, 30.2)a | 29.3 (27.9, 30.6)b | 33.5 (31.9, 35.1) | F = 9.49, p < .001, ηp2 = .06 |
| Education (% ≤ HH) | 71.9% | 66.4% | 45.8% | χ2 = 16.08, p < .001 |
| Employment (% NoW) | 50.5% | 40.7% | 60.4% | χ2 = 8.08, p < 0.05 |
| Gender (%F) | 65.4% | 72.6% | 66.7% | χ2 = 1.48, n.s. |
| Marital Status (% Married) | 44.7% | 45.1% | 35.4% | χ2 = 2.52, n.s. |
| Race (%NHW) | 77.6% | 59.3% | 34.4% | χ2 =38.87, p < .001 |
| Widespread pain | ||||
| % Subjects with WPS | .9% | 15.0% | 36.5% | χ2 =46.1, p < .001 |
| Number of sites – Total Group | .98 (.4, 1.6) | 3.58 (2.9, 4.2) | 7.4 (6.6, 8.1) | F = 9.49, p < .001, ηp2 = .06 |
| CLINICAL OUTCOMES | ||||
| WOMAC | ||||
| Total score (range 0–96) † | 3.5 (1.5, 5.4) ac | 18.4 (16.7, 20.2) b | 49.6 (47.5. 51.7) | F = 450, p < .001, ηp2 = .75 |
| Subscales | ||||
| Pain (range 0–20) † | .7 (.2, 1.2) ac | 4.2 (3.8, 4.7) b | 10.3 (9.7, 10.8) | F = 310.01, p < .001, ηp2 = .67 |
| Stiffness (range 0–8) † | .5 (.2, .7) ac | 2.1 (1.9, 2.3) b | 4.6 (4.3, 4.9) | F = 184.2, p < .001, ηp2 = .55 |
| Physical function (range 0–68) † | 2.3 (.8, 3.7) ac | 12.1 (10.8, 13.4) b | 34.8 (33.2, 36.4) | F = 392.91, p < .001, ηp2 = .72 |
| GCPS | ||||
| Characteristic Pain Intensity (range 0–100) † | 13.4 (9.8, 16.9) ac | 37.4 (34.1, 40.6) b | 59.4 (55.5, 63.2) | F = 130.21, p < .001, ηp2 = .46 |
| Disability Score (range 0–100) † | 4.9 (1.4, 8.6) ac | 24.93 (21.5, 28.3)b | 57.2 (53.1, 61.2) | F = 151.47, p < .001, ηp2 = .51 |
| Grading Chronic Pain Grade | χ2 = 252.63, p < .001 | |||
| 0 – Normal | 59 | 3 | 0 | |
| I - Low Pain Intensity | 42 | 75 | 13 | |
| II - High Pain Intensity | 5 | 24 | 25 | |
| III - Moderate Disability | 0 | 6 | 29 | |
| IV - High Disability | 0 | 3 | 27 | |
| Knee pain duration | ||||
| Pain on most days (months)† | .17 (−10.5, 19.5) a | 24.7 (11.8, 37.5) b | 57.8 (43.7, 71.8) | F = 11.66, p < .001, ηp2 = .10 |
Group comparisons
Significant group difference between the control and high symptomatic knee OA groups (p < .01, Bonferroni)
Significant group difference compared between the low and high symptomatic knee OA groups (p < .01, Bonferroni)
Significant group difference compared between the control and low symptomatic knee OA groups (p < .01, Bonferroni)
Covariates for adjusted analysis:
Controlling for race (0 = NHW, 1 = AA), age, widespread pain (0 = No, 1 = Yes), gender (0 = Female, 1 = Male), and study site (0 = UF, 1 = UAB) as a covariates.
Abbreviations: High School (HH); Not working (NoW); Non-Hispanic White (NHW); African American (AA); Body Mass Index (BMI); Yes in past year (Y); University of Florida (UF); Western Ontario and McMaster Universities Index of Osteoarthritis (WOMAC), Knee Injury Osteoarthritis Outcome Score Physical Function (KOOS-PS), Graded Chronic Pain Scale (GCPS).