Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Predictors of Interstitial Lung Disease in Early Systemic Sclerosis: A Prospective Longitudinal Study.
Assassi2, Shervin, Sharif2, Roozbeh, Lasky3, Robert E., McNearney1, Terry A., Martin3, Rosa Estrada Y, Draeger4, Hilda T., Nair3, Deepthi K.
Eli Lilly and Co, Indianapolis, IN
Univ of Texas Health Science Houston, TX
Univ of Texas Health Science Houston
Univ of Texas Health Science San Antonio, TX
Univ Texas Health Sci Ctr, Houston, TX
University of Calgary, AB, Canada
University of Texas-Houston, TX
UT Medical School, Houston, TX
Pulmonary involvement is the primary systemic sclerosis (SSc) - related cause of death. Forced vital capacity (FVC, expressed as a percentage of predicted value) has been validated as an outcome measure of interstitial lung disease (ILD) in SSc. Large prospective observational studies examining progression of ILD and the predictive significance of clinical and demographic variables have not been reported. The purpose of this study was to examine the association of baseline demographic and clinical characteristics with sequentially obtained measurements of FVC and to identify predictors of decline rate in FVC over time.
At the time of analysis, 266 patients were enrolled in Genetics versus Environment in Scleroderma Outcome Study (GENISOS), a prospective, observational cohort of patients with early SSc. In addition to pulmonary function tests (PFT), clinical and laboratory data were obtained from each patient. PFTs were performed at the baseline visit and annually thereafter. The predicted PFT values were calculated according to consistent reference values. The association of baseline parameters with sequentially obtained FVC was investigated in a generalized linear mixed model. Using a similar model, the predictors of decline rate in FVC were examined by the interaction term between the baseline variable and follow up time.
The cohort consisted of 125 white, 54 African American, and 77 Hispanic patients with average disease duration of 2.5 years at enrollment. The mean follow up time was 3.8 years, ranging up to 11.4 years; 59% of patients had diffuse cutaneous involvement. Only 22 patients (8.3%) had received cyclophosphamide before enrollment or during the follow up period. Upon review by a pulmonologist, 926 FVC measurements belonging to 244 patients fulfilled the American Thoracic Society criteria and were included in the analysis.
A number of baseline variables including African American ethnicity (p=0.002), diffuse disease type (p=0.012), baseline PFT values (p<0.001), modified Rodnan Skin Score (p=0.001), fibrosis on chest radiograph (p<0.001), subjective dyspnea (p<0.001), anti-topoisomerase antibodies (p<0.001), lung and skin subscores of Severity Index (p<0.001 and p=0.037, respectively) were associated with sequentially obtained FVC levels. Similar results were seen after adjustment for smoking status.
As expected, the follow up time in the study was associated with a decline in FVC (p<0.001). However, none of the baseline variables predicted the rate of decline in FVC over time. Specifically, ethnicity, disease type, baseline PFT values, Skin Score, chest radiographs, subjective dyspnea, autoantibody status, Medsger Severity Index subscores and smoking status did not predict the rate of decline in FVC. Moreover, an accelerated rate of decline in FVC was associated with poor survival (p=0.001).
Baseline clinical variables, associated with differential FVC levels did not predict the rate of decline in FVC. The association of faster decline in FVC with poor survival emphasizes the need for identification of predictive biomarkers by collection of genetic information and serial blood samples in cohort studies.
To cite this abstract, please use the following information:
Assassi, Shervin, Sharif, Roozbeh, Lasky, Robert E., McNearney, Terry A., Martin, Rosa Estrada Y, Draeger, Hilda T., et al; Predictors of Interstitial Lung Disease in Early Systemic Sclerosis: A Prospective Longitudinal Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1227