Table 3.

Final multiple linear regression models with the HAQ, SF-12, physical component score (PCS), and mental component score (MCS) as outcome. Explanatory variables that did not reach statistical significance in any of the models were excluded from the table. Number of observations = 2776.

Group	Explanatory Variables	HAQ		PCS		MCS
Group	Explanatory Variables	ß	p	ß	p	ß	p
Demography	Women	0.27	< 0.001	0	0.7	–2	0.003
	Age 50–75 yrs	0.10	< 0.001	–1	0.5	1	0.1
	Age > 75 yrs	0.25	< 0.001	–1	0.5	–1	0.3
	Education level, training	–0.05	0.04	–1	0.1	0	0.8
	Education level, higher	–0.09	0.001	–1	0.5	0	0.7
Lifestyle	BMI< 18.5	0.18	0.001	0	0.8	–3	0.1
	BMI 26–30	0.00	0.9	0	0.6	0	0.7
	BMI > 30	0.14	< 0.001	0	0.9	–1	0.2
	Exercise, weekly	–0.10	< 0.001	2	0.02	3	< 0.001
RA-related	Disease duration 3–10 yrs	0.02	0.5	0	0.9	–1	0.4
	Disease duration > 10 yrs	0.17	< 0.001	0	0.7	1	0.2
	Low DAS28 2.60–3.19	0.19	< 0.001	–1	0.2	–4	< 0.001
	Moderate DAS28 3.20–5.10	0.43	< 0.001	–3	< 0.001	–5	< 0.001
	High DAS28 > 5.10	0.87	< 0.001	–5	< 0.001	–7	< 0.001
	Extraarticular features (1)	0.07	0.003	–2	0.05	0	0.9
	Extraarticular features (≥ 2)	0.19	< 0.001	–2	0.2	–3	0.06
	Joint surgery (1 procedure)	0.12	< 0.001	1	0.3	–2	0.05
	Joint surgery (≥ 2 procedures)	0.55	< 0.001	3	0.02	–4	0.003
Treatment	MTX monotherapy	–0.02	0.4	0	0.8	0	1.0
	Anti-TNF-α monotherapy	0.12	0.008	3	0.1	–4	0.004
	MTX + anti-TNF-α	0.06	0.06	1	0.2	–1	0.3
	combination therapy
	Glucocorticoid use within	0.10	< 0.001	–2	0.01	0	0.7
	past month
Comorbidity, excluding RA	Comorbid conditions (1)	0.06	0.03	–1	0.4	0	0.6
	Comorbid conditions (2)	0.14	< 0.001	–1	0.4	–3	0.007
	Comorbid conditions (≥ 3)	0.21	< 0.001	–3	0.02	–2	0.03

Adjusted R²: HAQ: 0.41, PCS: 0.02, MCS: 0.05. Reference groups: male, age < 50 yrs; education level: elementary; body mass index 18.5–25; exercise: not regularly; disease duration: 0–2 years; DAS28 < 2.6; extra-articular features: none; joint surgery: none; MTX + anti-TNF-α therapy: none; glucocorticoid use: none; comorbid conditions: none.