Work Ability and Employment in Rheumatoid Arthritis: A Cross-Sectional Study on the Role of Muscle Strength and Lower Extremity Function

Table 4

Associations between grip strength, knee extensor strength, lower extremity function, and workability (workability index single item, WAS).

	Workability (WAS)
		Handgrip strength (HGS)			Knee extensor strength (KES)			Short physical performance battery score (SPPB)
Model	Variable	R^2	β	p-value	R^2	β	p-value	R^2	β	p-value
I	HGS/KES/SPP	0.06	0.25	0.012	0.17	0.39	<0.001	0.33	0.57	<0.001
I	HGS/KES/SPP	0.31	0.49	<0.001	0.33	0.52	<0.001	0.39	0.50	<0.001
	Age - years		-0.21	0.024		-0.14	0.132		-0.19	0.040
	Gender (female)		0.39	0.001		0.35	0.001		0.05	0.520
	Education (higher)		0.17	0.064		0.17	0.054		0.14	0.118
II	HGS/KES/SPP	0.45	0.25	0.039	0.45	0.36	0.001	0.51	0.35	<0.001
	Age - years		-0.15	0.107		-0.09	0.319		-0.14	0.132
	Gender (female)		0.24	0.032		0.26	0.006		0.06	0.469
	Education (higher)		0.06	0.471		0.08	0.328		0.06	0.505
	Disease duration - months		-0.13	0.189		-0.74	0.391		-0.06	0.511
	sDMARD therapy		-0.07	0.457		-0.10	0.239		0.08	0.317
	Comedication		-0.17	0.193		-0.21	0.104		-0.16	0.217
	Comorbidity		0.06	0.651		0.07	0.589		0.05	0.710
	Pain (VAS) - points		-0.36	< 0.001		-0.34	< 0.001		-0.39	<0.001

Linear regression analysis. β=standardised beta coefficient, HGS=handgrip strength, KES=knee extensor strength, SPPB=short physical performance battery, and s/b DMARD=synthetic/biological disease-modifying antirheumatic drug.
kg HGS/KES; per point of the SPPB score; II adjusted for sociodemographic variables p≤0.02 in univariate analysis; adjusted for sociodemographic and clinical variables p≤ 0.2 in univariate analysis.