Table III.
Subgroup analysis in studies on people with knee OA/pain
| Subgroup analysis | Effusion |
Synovial hypertrophy |
DS |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Number of studies | Prevalence (95% CI) | P∗ | Number of studies | Prevalence (95% CI) | P∗ | Number of studies | Prevalence (95% CI) | P∗ | |
| Threshold | |||||||||
| ≥4 mm | 11 | 52.5 (38–66.8) | 10 | 43.1 (26.5–60.5) | |||||
| ≥2 mm | 7 | 67.6 (55.8–78.3) | 2 | 25.5 (14.5–38.2) | |||||
| Absent or present | 6 | 32.7 (13.9–54.9) | 0.018 | 3 | 46.9 (0–99.7) | 0.234 | |||
| Sample size | |||||||||
| ≥100 subjects | 9 | 37.1 (20.8–55.2) | 5 | 21.4 (12.4–32.1) | 1 | ||||
| <100 subjects | 15 | 60.8 (48.4–72.5) | 0.034 | 10 | 52.8 (29.3–75.7) | 0.015 | 8 | ||
| Quality score | |||||||||
| <50% | 10 | 54.7 (32.1–76.4) | 5 | 47.1 (8.4–88.0) | 4 | 77 (54.5–93.7) | |||
| ≥50% | 14 | 49.2 (37.3–61.2) | 0.677 | 10 | 38.5 (24.7–53.4) | 0.726 | 5 | 6.0 (2.4–10.9) | <0.0001 |
| Case definition | |||||||||
| Knee OA | 14 | 58.7 (47–69.9) | 12 | 49 (30.5–67.6) | 7 | 43.8 (11.7–79.0) | |||
| Knee pain | 5 | 26 (5.6–54.4) | 0.037 | 3 | 15.2 (3.3–33.3) | 0.010 | 2 | 4.8 (1.9–8.7) | 0.009 |
| Study design | |||||||||
| Cross-sectional | 11 | 43.0 (28.0–58.0) | 5 | 25.0 (17.0–34.0) | 2 | 4.0 (2.0–8.0) | |||
| Case-control | 13 | 59.0 (41.0–76.0) | 0.180 | 10 | 50.0 (24.0–76.0) | 0.07 | 7 | 44.0 (13.0–78.0) | <0.0001 |
| Doppler settings | |||||||||
| Colour doppler | 2 | 87.0 (80.0–92.0) | |||||||
| Power doppler | 7 | 20.0 (4.0–42.0) | |||||||
| Not stated | 1 | 6.0 (3.0–12.0) | <0.0001 | ||||||
| Mean age | |||||||||
| ≤60 | 9 | 53.0 (42.0–63.0) | 5 | 24.0 (13.0–38.0) | 1 | ||||
| >60 | 13 | 61.0 (47.0–74.0) | 0.070 | 9 | 55.0 (28.0–80.0) | 0.050 | 7 | ||
| Women proportion | |||||||||
| ≤70 | 8 | 51.0 (29.0–73.0) | 7 | 31.0 (16.0–49.0) | 7 | ||||
| >70 | 14 | 59.0 (48.0–70.0) | 0.520 | 7 | 58.0 (30.0–84.0) | 0.110 | 1 | ||
∗
P-test for heterogeneity between subgroups.