Table II.

Comparison of clinical data of age- and sex-matched US and German patients with fibromyalgia syndrome.

	USA n=71	Germany n=71	p-value
Mean years since chronic widespread pain (SD)	16.0 (12.4)	7.6 (6.4)	Z = −5.5, p<0.0001
Mean years since fibromyalgia diagnosis (SD)	11.6 (8.0)	7.6 (6.4)	Z = −5.5; p<0.0001
Mean number of pain sites polysymptomatic distress scale (SD) (0–19)	11.2 (4.2)	12.9 (4.0)	Z = −2.3; p=0.02
Mean somatic symptom score polysymptomatic distress scale (SD) (0–12)	8.8 (2.1)	8.7 (2.2)	Z = −0.2; p=0.87
Mean total score polysymptomatic distress scale (SD) (0–31)	19.9 (5.1)	21.6 (5.1)	Z = −1.7; p=0.02
Psychological distress Patient Health Questionnaire 4 total score (SD) (0–12)	4.6 (3.4)	6.0 (3.5)	Z = −2.4; p=0.02
Patient Health Questionnaire potential depressive disorder n (%)	29 (43.9)	37 (56.1)	χ2 = 5.6; p=0.06
Patient Health Questionnaire potential anxiety disorder n (%)	27 (42.2)	37 (57.6)	χ2 = 2.8; p=0.06
Probable posttraumatic stress disorder n (%)	24 (33.8)	24 (33.8)
Mean Pain Disability Index total score (SD) (0–70)	37. (16.2)	36.0 (12.4)	Z = −0.8; p=0.45

Significant (Bonferroni adjusted) differences are marked as bold.