The Sjögren's Syndrome Damage Index--a damage index for use in clinical trials and observational studies in primary Sjögren's syndrome.
OBJECTIVE
To validate a tool for assessment of accumulated damage in patients with Primary SS (PSS).


METHODS
Of the total 114 patients fulfilling American-European Consensus Group (AECG) criteria for PSS 104 were included in the study and assessed by rheumatologists at T (time) = 0 months and T = 12 months. On each occasion, damage and activity data, and autoantibody status were collected. SF-36 and Profile of Fatigue and Discomfort-Sicca Symptoms Inventory (PROFAD-SSI) questionnaires were completed. Cross-sectional analysis of this data was subject to a process of expert validation by 11 ophthalmologists, 14 oral medicine specialists and 8 rheumatologists. Items were removed from the index if >or= 50% of respondents recommended exclusion. Statistical validation was performed on remaining items. Spearman's rank analysis was used to investigate associations between damage scores and other disease status measures and Wilcoxon matched-pair analysis to assess sensitivity to change in the damage score.


RESULTS
Based on the expert validation, a 29-item damage score was agreed incorporating ocular, oral and systemic domains. Total damage score correlated with disease duration at study entry (r = 0.436; P < 0.001), physical function as measured by SF-36 (r = 0.250, T = 0 months; r = 0.261 T = 12 months) and activity as measured by the Sjögren's Systemic Clinical Activity Index (r = 0.213, T = 0 months; r = 0.215, T =12 months). Ocular damage score correlated with the 'eye dry' domain of PROFAD-SSI (r = 0.228, T = 0 months; r = 0.365, T = 12 months). Other associations not present on both assessments were considered clinically insignificant. On Wilcoxon analysis, the index was sensitive to change over 12 months (z = -3.262; P < 0.01).


CONCLUSIONS
This study begins validation of a tool for collection of longitudinal damage data in PSS. We recommend further trial in both the experimental and clinical environment.
Barry
R J
RJ
Academic Unit of Ophthalmology, University of Birmingham, UK.
Sutcliffe
N
N
Isenberg
D A
DA
Price
E
E
Goldblatt
F
F
Adler
M
M
Canavan
A
A
Hamburger
J
J
Richards
A
A
Regan
M
M
Gadsby
K
K
Rigby
S
S
Jones
A
A
Mathew
R
R
Mulherin
D
D
Stevenson
A
A
Nightingale
P
P
Rauz
S
S
Bowman
S J
SJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D015352:Dry Eye Syndromes / Q000175:diagnosis; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D009059:Mouth Diseases / Q000175:diagnosis; D012720:Severity of Illness Index; D012859:Sjogren's Syndrome / Q000175:diagnosis*; D013997:Time Factors