Table 3

Means (M) and SD of discounting and lack of understanding (score ranges 1–5) of patients with rheumatoid arthritis (RA) and patients with fibromyalgia (FM) as experienced from the spouse, family, medical professionals, work environment and social services, and t value, 95% CI of difference, p value and Cohen's d of the group difference

		RA	FM	Test statistics
Type and source of invalidation		M (SD)	M (SD)	t	95% CI of difference	p	d
Discounting
a.	Spouse (n RA=106, n FM=124)	1.5 (0.5)^b	1.6 (0.6)^b–e	−2.0	−0.31 to 0.00	0.05	0.26
b.	Family (n RA=140, n FM=164)	1.7 (0.7)^a,c	2.2 (0.9)^a,c,e	−5.2	−0.64 to −0.28	<0.001	0.59
c.	Medical professionals (n RA=141, n FM=1161)	1.4 (0.5)^b,d,e	1.9 (0.8)^a,b,d,e	−6.8	−0.66 to −0.36	<0.001	0.77
d.	Work environment (n RA=53, n FM=82)	1.8 (0.7)^c	2.4 (0.9)^a,c	−4.6	−0.91 to −0.36	<0.001	0.78
e.	Social services (n RA=44, n FM=80)	2.0 (0.9)^c	3.1 (1.1)^a–c	−5.6	−1.42 to −0.68	<0.001	1.01
Lack of understanding
a.	Spouse (n RA=107, n FM=124)	1.8 (0.8)^b,d	1.9 (0.7)^b–e	−1.0	−0.29 to 0.09	0.31	0.13
b.	Family (n RA=140, n FM=163)	2.3 (0.8)^a,c	2.7 (0.9)^a,c–e	−4.5	−0.64 to −0.25	<0.001	0.50
c.	Medical professionals (n RA=141, n FM=163)	1.8 (0.7)^b,d,e	2.3 (0.8)^a,b,d,e	−5.2	−0.64 to −0.29	<0.001	0.59
d.	Work environment (n RA=53, n FM=82)	2.4 (0.8)^a,c	2.9 (0.8)^a–c	−3.4	−0.76 to −0.20	0.001	0.60
e.	Social services (n RA=44, n FM=80)	2.4 (0.9)^c	3.3 (1.0)^a–c	−5.3	−1.26 to −0.55	<0.001	0.97

After age had been controlled for, the p values of the invalidation differences between patients with rheumatoid arthritis and fibromyalgia did not change.
Superscripts indicate the sources that differ significantly from the mentioned source.