were calculated (see Tables II and III). An SMD of 0.20–0.49
is considered small, 0.50–0.79 moderate, and ≥ 0.80 large (29).
All analyses were performed using the statistical software
package IBM SPSS 23.0 for Windows® (SPSS Inc., Chicago,
IL, USA).
RESULTS
T. Benz et al.
130
Patients
The flow chart of participants is shown in Fig. 1.
Complete data were available for analysis of 136 GSP
and 35 ISP in sample 1, and 63 GSP and 61 ISP in
sample 2. Reasons for exclusion with exact numbers
are shown in Fig. 1.
Sociodemographic variables and disease-relevant
characteristics are given in Table I. All participants were
Caucasian. The mean participant’s age was comparable
in both samples. Comparing sample 1 with sample 2, an
important difference was found in sex, with no signifi-
cant difference in sample 1, but in sample 2 more males
participated in the study (p < 0.001). In education, ISP
were significantly less educated than GSP, especially in
sample 2. In sample 1, higher education was reported
in GSP (73%) vs ISP (9%) in sample 1 and in sample
2 (62% vs 15%). Significant occupational differences
were found in sample 1 (p < 0.001), with 80% of the
ISP being unemployed. In sports, ISP were less active
(p = 0.034). In both samples, most ISP were living with a
partner. In sample 1, 66% of ISP had 3 or more comorbi-
dities in contrast to 43% of the GSP. In both samples, this
characteristic was comparable. In summary, ISP were
less educated, less occupied, more often married and
less active in sports than the GSP, especially in sample 1.
Sensitivity analysis
Age, sex and SF-36 scores for completers were
compared with the baseline scores of drop-outs for
ISP and GSP in sample 1 and sample 2 each (i.e. 4
comparisons). No significant differences were found
in all 4 comparisons in age and sex. In sample 1, sig-
nificant differences were found in the GSP in Physical
functioning (p = 0.034) and in the ISP in Role Physical
(p = 0.032) and in Role emotional (p = 0.016). In sample
2, the only significant difference was in the GSP in
Role emotional (p = 0.011). All other scores differences
within the 4 groups were not significant.
Table I. Sociodemographic and disease-related characteristics at baseline
Sample 1
Age, years, mean (SD)
Female, %
Education, %
No school
Basic school (8–9 years)
Vocational training
College/high school
Technical college
University
Occupation, %
Not working
Part-time work (7–41 h/week)
Full-time work (≥ 42 h/week)
Living conditions, %
Alone
With partner
With other persons
Sport, %
No sports
<1 h/week
1–2 h/week
>2 h/ week
Diagnosis, %
Fibromyalgia/Generalized
widespread pain
Chronic non-specific back pain
Comorbidities, %
None
1
2
3
4
5
≥ 6
Sample 2
German-speaking
patients (n = 136) Italian-speaking
patients (n = 35)
German-speaking patients
(n = 63) Italian-speaking
patients (n = 61) 46.5 (12.1)
80.1 48.9 (7.7)
74.3
p-value
48.6 (10.0)
85.7 49.9 (9.0)
45.9 0.260
< 0.001
0.0
27.2
55.1
11.0
2.9
3.7 20.0
71.4
5.7
2.9
0.0
0.0
< 0.001 3.2
34.9
46.0
12.7
1.6
1.6 7.3
78.2
10.9
1.8
0.0
1.8 < 0.001
36.0
43.4
16.9 80.0
14.3
2.9 < 0.001 66.1
27.5
6.4 67.9
23.1
9.0 0.949
22.1
71.3
6.6 2.9
91.4
5.7 0.027 27.0
54.0
19.0 12.5
80.4
7.1 0.022
48.5
16.9
23.5
11.0 77.4
6.5
12.9
3.2 0.034 50.8
23.8
12.7
12.7 60.0
10.9
16.4
12.7 0.324
59.6 48.6 0.241 42.9 44.3 0.875
40.4 51.4 57.1 55.7 9.6
20.6
27.2
23.5
8.1
5.1
5.9 2.9
11.4
20.0
31.4
20.0
11.4
2.9 7.9
15.9
14.3
23.8
19.0
9.5
9.5 4.9
23.0
31.1
14.8
8.2
1.6
1.6
h/week: hours per week; p-value: p-values with significance level set at ≤ 0.05.
www.medicaljournals.se/jrm
p-value
0.132
0.448
0.179
0.300