Patient-reported outcomes in primary Sjogren's syndrome: comparison of the long and short versions of the Profile of Fatigue and Discomfort--Sicca Symptoms Inventory.
OBJECTIVE
The long-form 64-item Profile of Fatigue and Discomfort--Sicca Symptoms Inventory (PROFAD-SSI) questionnaire was developed as a patient-reported assessment tool for use in primary SS (PSS) and other rheumatic disorders. In this study, we assess whether the (shorter and more practical) 19-item PROFAD-SSI-SF (short form) gives similar results and whether a still briefer version using visual analogue scales (VASs) is feasible.


METHODS
Questionnaire surveys comprising the long and short versions of the PROFAD-SSI were mailed to 43 patients with PSS and 50 patients with RA, who were asked to complete these contemporaneously as well as repeating the process 1 month later. PSS patients also completed a series of VASs comprising fatigue and sicca domains of the SSI.


RESULTS
Surveys were returned from 35 PSS patients and 35 RA patients. All domains of the long- and short-form PROFAD-SSI showed strong correlations (Spearman rho between 0.779 and 0.996, P < 0.01). Factor analysis generally confirmed the previously validated domain structure with Cronbach's alpha = 0.99. The PROFAD-SF somatic fatigue domain correlated more strongly with a fatigue VAS than did the mental fatigue domain. The SSI-SF domain scores correlated with equivalent VAS scores.


CONCLUSIONS
The long- and short-form PROFAD-SSI questionnaires correlate closely suggesting that the PROFAD-SF is valid as an outcome tool. Preliminary data also suggest that an even briefer form with compression of the domains into single VAS is also feasible.
Bowman
S J
SJ
Department of Rheumatology, University Hospital Birmingham NHS Foundation Trust (Selly Oak), Raddlebarn Road, Birmingham B296JD, UK. simon.bowman@uhb.nhs.uk
Hamburger
J
J
Richards
A
A
Barry
R J
RJ
Rauz
S
S
D000368:Aged; D004185:Disability Evaluation; D005221:Fatigue; D005260:Female; D006801:Humans; D008875:Middle Aged; D011594:Psychometrics; D012720:Severity of Illness Index; D012859:Sjogren's Syndrome / Q000503:physiopathology / Q000523:psychology*; D011795:Surveys and Questionnaires