Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
A Disease Damage Index for Canadians with Systemic Sclerosis
Keen1, Kevin, Walker2, Jenny, Hudson3, Marie, Bassarguina1, Viktoria, Baron4, Murray, Canadian Scleroderma Research Group,
Disease activity and damage indices facilitate collection of standardized information and provide an important means of objectively documenting a subject's disease state. A disease severity index is a composite measure of activity and damage. Disease severity indices for systemic sclerosis (SSc) have been developed in the United States and Sweden. An SSc disease activity index has been developed in Europe and another is under development in Canada. The purpose of this ongoing study is to develop a disease damage index for SSc.
A cross-sectional analysis of 654 patients enrolled in the Canadian Scleroderma Research Group Registry was undertaken and after review, 42 variables encompassing 9 organ systems were retained for further study. Rheumatologists' global assessment of damage was chosen as the gold standard in the development of an aggregate damage score (the Canadian Scleroderma Damage Index, or CSDI). Statistical methods included multiple linear regression and multivariate techniques such as principal component analysis and factor analysis.
Among the 654 subjects, the limited-diffuse ratio was 1.3:1. The female-male ratios were 8.6:1 for limited SSc (lSSc) and 4.3:1 for diffuse SSc (dSSc). Mean global damage was 2.50 (SD = 2.19) for 112 lSSc subjects with complete data and 4.12 (SD = 2.51) for 65 dSSc subjects with complete data. Both means are somewhat low with mean global damage for lSSc being significantly lower than that of dSSc (P < 0.0001). The 42 explanatory variables in the separate multiple linear regression models for lSSc and dSSc were able to account for 72% and 86%, respectively, of the variation in the rheumatologists' global assessment of damage. The most meaningful among the explanatory variables were the modified Rodnan skin score for the whole body, the number of digits with loss of pulp, whether there had been an SSc renal crisis, the New York Heart Association class, whether the electrocardiogram was abnormal, whether pericardial effusion was present, and whether oxygen was being used at home.
Preliminary damage scales have been developed for patients with lSSc and dSSc. These will be tested among a larger sample of rheumatologists and are presented for peer review.
To cite this abstract, please use the following information:
Keen, Kevin, Walker, Jenny, Hudson, Marie, Bassarguina, Viktoria, Baron, Murray, Canadian Scleroderma Research Group, ; A Disease Damage Index for Canadians with Systemic Sclerosis [abstract]. Arthritis Rheum 2009;60 Suppl 10 :453