A cross-sectional study on self-reported physical and mental health-related quality of life in rheumatoid arthritis and the role of illness perception

Table 4 Regression models between illness perception items, patient characteristics, social support and dependent variable physical health-related quality of life (SF-36)

	Model 1 (Block 1)		Model 2 (Block 1–2)		Model 3 (Block 1–3)		Model 4 (Block 1–4)
	R²	β	R²	β	R²	β	R²	β
Block 1
Illness perception	0.511		0.536		0.565		.0.565
Identity		−0.07		−0.08		−0.05		−0.05
Consequences		− 0.37^**		−0.39^**		− 0.34^**		−0.34^**
Treatment control		0.04		0.06		0.04		0.04
Personal control		0.14		0.08		0.03		0.03
Illness coherence		0.01		−0.04		−0.04		−0.05
Timeline (cyclical)		−0.39^**		−0.36^**		−0.30^**		−0.30^**
Emotional representation		−0.05		−0.02		− 0.01		- 0.00
Block 2
Demographic characteristics
Age				−0.16		− 0.16		− 0.16
Marital status				−0.06		−0.08		− 0.08
Educational level				−0.04		− 0.07		−0.07
Block 3
Clinical characteristics
Additional medication						0.03		0.03
Co-morbidity						−0.08		−0.08
Disease activity						−0.03		−0.03
Pain						0.01		0.01
Functional disability						−0.18		−0.18
Fatigue						−0.02		−0.02
Block 4
Social support
Detrimental interaction								0.08
R² change			0.53			0.56		0.63

*p ≤ 0.05;** p ≤ 0.01; R² is adjusted R²; β is standardized coefficient β
All variables with a p-value < 0.2 in univariate analysis were included in the regression model

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