Measurement of global functional performance in patients with rheumatoid arthritis using rheumatology function tests

Table 1 Correlation between rheumatology function tests (RFTs) and variables measured as criterion standards in 779 patients with rheumatoid arthritis

	Primary RFT scales
Criterion variable	Grip strength	Walking velocity	Button speed	Derived global physical function scale
Pain	-0.16	-0.19	-0.13	-0.19**
Tender-joint count	-0.44	-0.37	-0.34	-0.46**
Swollen-joint count	-0.32	-0.16	-0.19	-0.27**
Deformed-joint count	-0.36	-0.35	-0.45	-0.46**
MHAQ	-0.54	-0.60	-0.53	-0.66***
SF36PF	0.52	0.65	0.55	0.68**
Steinbrocker Functional Class	-0.47	-0.63	-0.59	-0.67***
Latent disability scale	0.59	0.72	0.64	0.78***

Pearson correlation coefficients were compared after Fisher's z-transformation [22, 23]. Significance of comparisons was set at P ≤ 0.002. **Correlation between criterion variable and global physical function is significantly stronger than with two of the primary scales. ***Correlation between criterion variable and global physical function is significantly stronger than with three of the primary scales. MHAQ, Modified Health Assessment Questionnaire; SF36PF, short-form 36 physical function scale.

ISSN: 1478-6362