Table 3. Knee OA crude and stepwise ANCOVA adjusted WOMAC and RAND-36 scores§.
| Knee OA patients | Crude and Model 3 (Fully adjusted model) | Model 1 | Model 2 | |||
|---|---|---|---|---|---|---|
| Unlikely NP (n = 75) | Possible NP (n = 63) | Unlikely NP | Possible NP | Unlikely NP | Possible NP | |
| WOMAC score | ||||||
| Total | Crude: 68.4 (64.3–72.5) | 44.6 (40.7–48.5)c* | 67.2 (63.5–71.0) | 46.2 (41.9–50.5)d* | 67.5 (62.6–72.5) | 47.8 (43.0–52.6)d* |
| Model 3: 62.5 (58.1–66.9) | 52.4 (48.1–56.7)d* | |||||
| Pain | Crude: 67.7 (63.2–72.2) | 45.0 (40.6–49.4)* | 66.4 (62.2–70.6) | 46.8 (42.2–51.4)a* | 67.9 (62.3–73.5) | 48.0 (42.8–53.3)a* |
| Model 3: 61.1 (56.4–65.9) | 54.1 (49.6–58.5)a* | |||||
| Stiffness | Crude: 62.5 (57.6–67.4) | 39.5 (34.9–44.1)* | 61.5 (56.8–66.2) | 40.6 (35.4–45.8)a* | 61.8 (55.7–67.9) | 42.3 (36.5–48.0)a* |
| Model 3: 57.1 (51.2–63.0) | 47.0 (41.4–52.5)a* | |||||
| Function | Crude: 69.2 (65–73.4) | 45.6 (41.5–49.7)c* | 68.1 (64.2–72.0)* | 47.1 (42.7–51.6)d* | 67.8 (62.6–72.9)* | 48.2 (43.1–53.2)d* |
| Model 3: 63.4 (58.5–68.2) | 52.8 (48.1–57.5)d* | |||||
| RAND-36 score | ||||||
| Physical Functioning | Crude: 56.6 (51.6–61.6)a | 38.1 (33.3–42.9)* | 55.5 (50.8–60.1)a | 39.8 (34.7–44.9)a* | 55.7 (49.8–61.6)a | 41.0 (35.5–46.5)a* |
| Model 3: 53.4 (47.3–59.5)a | 43.7 (38.1–49.4)a* | |||||
| Role-Physical | Crude: 53.7 (44.3–63.1) | 38.3 ± 28.1–48.1a* | 52.1 (42.5–61.6) | 39.3 (28.6–49.9)b | 56.2 (43.8–68.5) | 41.9 (30.2–53.6)b |
| Model 3: 54.5 (41.4–67.5) | 44.6 (32.3–57.0)b | |||||
| Bodily Pain | Crude: 48.8 (44–53.6) | 54.1 (49.2–59)a | 49.7 (44.9–54.4) | 53.1 (47.8–58.4)b | 49.2 (43.0–55.5) | 51.7 (45.8–57.6)b |
| Model 3: 50.3 (43.7–56.9) | 50.5 (44.3–56.8)b | |||||
| General Health | Crude: 58.2 (54.6–61.8) | 56.7 (52.6–60.8)a | 57.9 (54.2–61.6) | 56.7 (52.6–60.8)b | 61.0 (56.2–65.7) | 58.1 (53.5–62.6)b |
| Model 3: 60.2 (55.2–65.3) | 58.0 (53.3–62.8)b | |||||
| Vitality | Crude: 57 (53.4–60.6) | 52.7 (49.1–56.3)a | 56.4 (52.9–60.0) | 53.0 (49.1–56.9)b | 59.9 (52.3–61.6) | 53.2 (48.8–57.6)b |
| Model 3: 57.8 (52.9–62.7) | 52.4 (47.7–57.0)b | |||||
| Social Functioning | Crude: 59.2 (53.9–64.5) | 53.0 (47.4–58.6)a | 58.6 (53.3–63.9) | 53.7 (47.8–59.6)b | 59.8 (53.1–66.5) | 54.1 (47.8–60.4)b |
| Model 3: 61.1 (54.0–68.2) | 52.9 (46.2–59.6)b | |||||
| Role-Emotional | Crude: 83.6 (76.3–90.9) | 72.6 (62.6–82.6)a | 82.0 (73.7–90.3) | 73.7 (64.4–83.0)b | 87.4 (76.6–98.2) | 77.7 (67.5–88.0)b |
| Model 3: 88.2 (76.8–99.7) | 78.5 (67.7–89.3)b | |||||
| Mental Health | Crude: 68.2 (65.3–71.1) | 65.0 (61.5–68.5)a | 67.6 (64.5–70.7) | 65.5 (62.0–68.9)b | 69.4 (65.5–73.3) | 66.9 (63.2–70.6)b |
| Model 3: 69.5 (65.4–73.7) | 67.0 (63.1–70.9)b | |||||
§ All values are presented as mean (95% CI)
Crude: Unadjusted values
Model 1: adjusted for age, sex, BMI
Model 2: Additionally adjusted for back disorders, painful body regions, comorbidities and previous surgery (includes model 1)
Model 3 / Full: Fully adjusted model, additionally adjusted for pain intensity and analgesic usage (includes model 2)
Unlikely NP = unlikely neuropathic pain phenotype (mPDQ≤12); Possible NP = possible neuropathic pain phenotype (mPDQ>12); WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index; RAND-36 = RAND 36-item Health Survey; WOMAC/RAND-36 score = 100 indicates no symptoms/problems and 0 indicates extreme symptoms/problems
a There was 1 individual with missing data on this variable
b There were 2 individuals with missing data on this variable
c There were 3 individuals with missing data on this variable
d There were 4 individuals with missing data on this variable
* A P-value <0.05 was considered to be statistically significant