319SF-36 has been used as a proxy measure of fatigue in several conditions. FSS and
fatigue VAS are positive scales in that higher values mean higher fatigue levels,
whereas FACIT-F and vitality have the opposite direction [ 66 ].
Challenges to Outcome Measures Assessment in Sjögren’s
Syndrome
The development of assessment tools in SS has faced several challenges. The fi rst
challenge is the lack of a gold standard for outcome measures. So far, there is no
single or set of clinical and immune-pathogenic markers that can be reliably used to
refl ect adequately all aspects of outcomes in SS. This lack of common assessment
criteria led to the application of various invalidated assessment tools in clinical tri-
als, making comparison of the effi cacy of treatment between studies extremely dif-
fi cult. In addition, there is lack of knowledge of the nature and frequency of disease
exacerbations or remissions. This is supported by the data documenting delays of
5–10 years after symptom onset prior to diagnosis [ 66 , 67 ]. Furthermore, this partly
silent and partly unknown clinical course of SS has made it diffi cult to defi ne what
characterizes active disease in SS and how to stratify clinical disease manifestations
into features of activity and features of damage/chronicity. Such distinction has
been proven valuable in other chronic infl ammatory arthritic conditions.
Since the sicca symptoms are the hallmarks of the syndrome, they became the
primary targets for objective assessment (such as Schirmer’s test [ 36 ] and Saliva
Ferning test [ 68 ]), as well as for assessment as outcome measures of management.
On the other hand, though comorbidities have been reported in association with SS,
there is not, so far, any tool for assessment. A multidimensional PROMs question-
naire remains an unmet demand, and most of the tools used currently were origi-
nally designed for other rheumatic diseases [ 69 ] or generic questionnaires [ 70 ].
Further work is still needed in this aspect.
Conclusion
PROMs questionnaires remain one of the best ways to measure the disease activity
as well as its impact on the patient’s daily living. In SS, patient- reported symptoms
such as dryness or fatigue have been used as primary outcome measures in clinical
trials. PROMs instruments in SS should not only focus on the ability to identify and
diagnose the problem such as dry eye/mouth, measure the prevalence of the condi-
tion, and assess the severity as well as frequency of symptoms, but also enable the
assessment of change of the patient’s condition in response to management. From a
clinician’s perspective, this will help in setting realistic expectations and in moni-
toring the improvement level in individual patients. Acknowledgment The authors
12 PROMs for Sjögren’s Syndrome