Date of Award


Degree Type


Degree Name

Master of Science


Epidemiology and Biostatistics


Dr. Janet Pope

Second Advisor

Dr. Kathy Speechley

Third Advisor

Dr. Allen Donner


Systemic Sclerosis (Scleroderma, SSc) is a rare and chronic connective tissue disease of unknown etiology. The current classification criteria for SSc were created in 1980 and fail to classify 12% of individuals with SSc who should be classified with its limited forms. A Delphi Consensus exercise of three rounds was conducted among an international team of rheumatologists to determine which items from a list of potential criteria best classify SSc. Cluster analysis was used to reduce the final consensus list to criteria with a best fit. The Canadian Scleroderma Research Group (CSRG) patient database was used to determine the proportion of patients the criteria classify. The Delphi exercise achieved consensus for 18 items and cluster analysis identified criteria filling into four categories: tissue damage, major skin involvement, capillary characteristics and auto-antibodies. The addition of dilated capillaries, telangiectasis, Raynaud’s phenomenon, auto-antibodies, esophogeal dysmotility / dysphagia and calcinosis can classify 94% of the CSRG database. Updated classification criteria will improve disease identification and case definitions for research purposes, contributing to SSc research, patient treatment and prognosis.



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