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as a result of its shorter completion time. Other questionnaires used to assess quality
of life in patients suffering from dryness of the eye (such as, 25-item National Eye
Institute Visual Function Questionnaire and Texas Eye Research and Technology
Center DEQ) were fairly limited in that assessment.
Fatigue
Fatigue is one of the main SS manifestations, reported by about 75 % of the patients,
and is a key predictor of reduced social activities and work productivity [ 58 – 60 ].
Fatigue was identifi ed as a predictor of SF-36 domain scores in a variety of studies.
In a study that included 94 primary SS patients, pain, helplessness, and depression
were predictors of physical and mental fatigue [ 42 ]. The best approach to assess
fatigue has not yet been defi ned, visual/numerical analogue scales have been used
in standard clinical practice as well as research studies. The ESSPRI contains two
Likert scales (0–10) on fatigue (physical and mental) that can be used for patient
assessment [ 20 ]. The Profi le of Fatigue and Discomfort—Sicca Symptoms Inventory
(PROFAD-SSI) questionnaire [ 61 ] was developed specifi cally to assess fatigue in
primary SS patients. It includes 64 questions in eight domains (somatic fatigue,
mental fatigue, arthralgia, vascular dysfunction, oral dryness, ocular dryness, cuta-
neous dryness, and vaginal dryness) scored on an 8-point (0–7) Likert scale. The
domains are made up of one or more facets, which each contain one or more related
questions. However, this long questionnaire is inconvenient for use in a clinical trial
context, where several other questionnaires may also need to be completed. The
somatic and mental fatigue domain scores can also be summated to form the Profi le
of Fatigue (PROF) score; the fatigue, arthralgia, and vascular dysfunction domains
to form the PROFAD score; and the sicca domains to form the SSI score. A shorter
version (PROFAD-SSI-SF) with 19 questions, each question refl ecting a single
facet of the long-form (PROFAD- SSI- LF), was developed to tackle this long ver-
sion hurdle [ 59 ]. These 19 questions can still be grouped into the same eight domains
and summary scores as above. The long form of the PROFAD-SSI questionnaire
was compared to the short form. Furthermore, a comparison of the short form with
a briefer (“brev”) version comprising a series of visual analogue scales (VAS) rep-
resenting the major domains of the PROFAD-SSI that may be particularly useful in
clinical trials in PSS was carried out. The long- and short-form PROFAD-SSI ques-
tionnaires 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 a single VAS is also feasible [ 62 , 63 ].
Among other instruments used to assess fatigue in rheumatic disease studies,
including SS, is the Fatigue Severity Scale (FSS), Functional Assessment of Chronic
Illness Therapy-Fatigue (FACIT-F), and different VAS variants. FSS assesses func-
tional issues during the preceding 2 weeks [ 64 ]. FACIT-F is a general fatigue
measure with emphasis on daily life function [ 65 ]. In contrast, SF-36 assesses dif-
ferent health aspects during the preceding 4 weeks [ 25 ]. The vitality domain of
M.O. Hegazi et al.