Appendix Table 4.
Baseline Characteristics Associated With Missingness at Follow-up Evaluation Visits*
| Baseline Characteristic | Week 12
|
Week 24
|
Week 52
|
|||
|---|---|---|---|---|---|---|
| Missing Data (n = 38) | Data Present (n = 166) | Missing Data (n = 51) | Data Present (n = 153) | Missing Data (n = 63) | Data Present (n = 141) | |
| Mean age (SD), y | 58.1 (9.9) | 60.7 (10.5) | 58.5 (9.7) | 60.8 (10.7) | 59.3 (11.6) | 60.6 (9.9) |
|
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| Female, % | 63.2 | 71.7 | 66.7 | 71.2 | 66.7 | 71.6 |
| Race, % | ||||||
|
| ||||||
| White | 39.5 | 56.0 | 35.3 | 58.8 | 38.1 | 59.6 |
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| Black | 44.7 | 33.1 | 45.1 | 32.0 | 47.6 | 29.8 |
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| Other | 15.8 | 10.8 | 19.6 | 9.2 | 14.3 | 10.6 |
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| Education, % | ||||||
| High school or less | 15.8 | 16.9 | 19.6 | 15.7 | 19.1 | 15.6 |
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| Some college/trade | 50.0 | 34.4 | 45.1 | 34.6 | 47.6 | 32.6 |
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| College graduate | 10.5 | 23.5 | 15.7 | 22.9 | 17.5 | 22.7 |
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| Graduate school | 23.7 | 25.3 | 19.6 | 26.8 | 15.9 | 29.1 |
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| Married/living with partner, % | 39.5 | 28.9 | 33.3 | 30.1 | 36.5 | 28.4 |
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| Living alone, % | 50.0 | 53.0 | 52.9 | 52.3. | 47.6 | 54.6 |
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| Employment, % | ||||||
| Full-time | 10.5 | 19.9 | 17.7 | 18.3 | 19.1 | 17.7 |
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| Part-time | 13.2 | 11.5 | 13.7 | 11.1 | 14.3 | 10.6 |
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| Retired | 31.6 | 28.9 | 27.5 | 30.1 | 23.8 | 31.9 |
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| Other | 44.7 | 39.8 | 41.2 | 40.5 | 42.9 | 39.7 |
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| History of knee injury, % | 47.4 | 42.8 | 43.1 | 43.8 | 42.9 | 44.0 |
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| Arthroscopy, % | 23.7 | 18.1 | 21.6 | 18.3 | 25.4 | 16.3 |
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| Effusion, % | 44.7 | 46.3 | 46.0 | 46.0 | 45.9 | 46.0 |
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| Randomly assigned to Tai Chi, % | 50.0 | 52.4 | 45.1 | 54.3 | 54.0 | 51.1 |
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| Mean body mass index (SD), kg/m2 | 34.4 (8.2) | 32.4 (6.9) | 35.4 (8.1) | 31.9 (6.6) | 33.8 (7.9) | 32.4 (6.8) |
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| Mean pain duration (SD), y | 6.9 (5.6) | 8.6 (10.8) | 8.8 (11.0) | 8.2 (9.8) | 8.6 (11.1) | 8.2 (9.6) |
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| ||||||
| Kellgren-Lawrence grade, %† | ||||||
| 0–2 | 35.1 | 47.0 | 40.0 | 46.4 | 34.4 | 49.3 |
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| 3 | 43.2 | 34.8 | 40.0 | 35.1 | 42.6 | 33.6 |
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| 4 | 21.6 | 18.3 | 20.0 | 18.5 | 23.0 | 17.1 |
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| Joint symptoms, % | 68.4 | 68.1 | 72.6 | 66.7 | 76.2 | 64.5 |
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| ||||||
| Mean Arthritis Self-Efficacy Scale score (SD) (range, 1–10)‡ | 6.0 (2.2) | 6.3 (2.1) | 6.3 (2.1) | 6.2 (2.1) | 6.1 (2.0) | 6.3 (2.2) |
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| ||||||
| Mean Outcome Expectations Scale for Randomized Intervention score (SD) (range, 1–5) | 3.9 (0.7) | 3.9 (0.6) | 3.9 (0.7) | 3.9 (0.6) | 3.9 (0.7) | 3.9 (0.6) |
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| Self-reported comorbidities, % | ||||||
| Heart disease | 5.3 | 8.4 | 7.8 | 7.8 | 11.1 | 6.4 |
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| ||||||
| Hypertension | 44.7 | 51.2 | 49.0 | 50.3 | 50.8 | 49.7 |
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| Diabetes | 18.4 | 18.7 | 19.6 | 18.3 | 17.5 | 19.2 |
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| Mean WOMAC pain score (SD) (range, 0–500), mm§ | 256.5 (89.0) | 253.3 (100.7) | 261.1 (92.7) | 251.5 (100.4) | 261.7 (89.3) | 250.4 (102.3) |
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| ||||||
| Mean WOMAC physical function score (SD) (range, 0–1700), mm§ | 958.2 (274.2) | 885.4 (367.3) | 971.0 (294.9) | 875.0 (367.3) | 951.6 (310.4) | 875.5 (368.2) |
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| ||||||
| Mean WOMAC stiffness score (SD) (range, 0–200), mm§ | 119.0 (38.3) | 116.6 (47.6) | 119.5 (39.2) | 116.2 (48.1) | 115.9 (42.5) | 117.5 (47.6) |
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| ||||||
| Mean Patient Global Visual Analogue Scale score (SD) (range, 0–10), cm§ | 5.4 (2.3) | 5.2 (2.2) | 5.5 (2.1) | 5.1 (2.2) | 5.6 (2.1) | 5.0 (2.2) |
| Mean SF-36 score (SD) (range, 0–100)‡ | ||||||
|
| ||||||
| Physical component | 34.4 (9.5) | 37.1 (9.0) | 34.1 (9.3) | 37.4 (8.9) | 34.9 (8.8) | 37.3 (9.2) |
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| Mental component | 52.5 (8.0) | 52.5 (9.5) | 52.1 (7.8) | 52.7 (9.7) | 52.6 (8.6) | 52.5 (9.5) |
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| Mean Beck Depression Inventory-II score (SD) (range, 0–63)§ | 7.4 (8.9) | 7.7 (8.6) | 6.8 (8.0) | 7.9 (8.8) | 7.1 (8.6) | 7.9 (8.7) |
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| Mean perceived stress score (SD) (range, 0–40)§ | 13.0 (6.6) | 13.3 (7.1) | 12.6 (6.9) | 13.5 (7.0) | 13.3 (6.9) | 13.3 (7.0) |
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| Mean 6-min walk score (SD), m | 368.8 (99.3) | 401.6 (87.1) | 369.0 (93.3) | 404.4 (87.5) | 371.7 (102.1) | 406.0 (82.5) |
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| Mean 20-m walk score (SD), s | 19.8 (5.0) | 18.8 (5.4) | 19.9 (4.8) | 18.7 (5.5) | 19.8 (5.0) | 18.6 (5.4) |
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| ||||||
| Analgesic use, % | 50.0 | 31.1 | 41.2 | 32.5 | 42.9 | 30.9 |
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| ||||||
| NSAID use, % | 59.5 | 61.2 | 56.0 | 62.5 | 58.1 | 62.1 |
NSAID = nonsteroidal anti-inflammatory drug; SF-36 = 36-Item Short Form Health Survey; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index.
*
Boldface values indicate statistically significant differences between groups. The chi-square test was used for categorical variables, and the t test was used for continuous variables.
†
Five participants who had a score of 0 met eligibility criteria because they had a definite osteophyte in the patellofemoral region.
‡
Higher scores indicate better status.
§
Higher scores indicate more severe symptoms.