Construct (Cronbach α test) and external validity of the different clinical and ultrasonographic scoring systems evaluated in 76 patients with active rheumatoid arthritis
Scoring system | Construct validity (Cronbach α test) | External validity (vs CRP: coefficient of correlation) |
---|---|---|
Joint count* | ||
20 Clinical | 0.76 | 0.28 |
20 US B mode | 0.76 | 0.28 |
20 US power Doppler | 0.81 | 0.37 |
28 Clinical | 0.78 | 0.35 |
28 US B mode | 0.87 | 0.35 |
28 US power Doppler | 0.86 | 0.43 |
38 Clinical | 0.78 | 0.35 |
38 US B mode | 0.86 | 0.30 |
38 US power Doppler | 0.85 | 0.39 |
Joint score* | ||
20 Clinical | 0.86 | 0.29 |
20 US B mode | 0.83 | 0.28 |
20 US power Doppler | 0.82 | 0.34 |
28 Clinical | 0.85 | 0.31 |
28 US B mode | 0.89 | 0.39 |
28 US power Doppler | 0.84 | 0.38 |
38 Clinical | 0.88 | 0.31 |
38 US B mode | 0.88 | 0.34 |
38 US power Doppler | 0.85 | 0.37 |
↵* See Patients and methods section for the definition of count versus score and for the description of the evaluated joints.
CRP, C reactive protein; US, ultrasound.