Lung Function and Survival In Systemic Sclerosis Associated Interstitial Lung Disease

Samar M. Shadly¹, Sindhu R. Johnson², Cathy Chau³ and Theodore K. Marras⁴, ¹Medicine, University Health Network Interstitial Lung Diseases Program, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada, ²Medicine, Division of Rheumatology, Toronto Western Hospital, University Health Network Pulmonary Hypertension Programme, Toronto General Hospital, Mount Sinai Hospital and University of Toronto, Toronto, ON, Canada, ³Medicine, Toronto Scleroderma Program, Toronto Western Hospital, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada, ⁴Medicine, University Health Network Interstitial Lung Diseases Program, University Health Network and Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada

Meeting: 2013 ACR/ARHP Annual Meeting

Keywords: Scleredema and lung

Session Information

Title: Systemic Sclerosis, Fibrosing Syndromes, and Raynaud’s - Clinical Aspects and Therapeutics I

Session Type: Abstract Submissions (ACR)

Background/Purpose:

We sought to assess for an association between baseline forced vital capacity (FVC) and diffusion capacity (DLCO) with mortality, and to identify threshold values of forced vital capacity (FVC) and diffusion capacity (DLCO) that predict mortality in systemic sclerosis-associated interstitial lung disease (SSc-ILD).

Methods:

The Toronto ILD Program and the Toronto Scleroderma Program cohorts were used to identify SSc-ILD patients. Data were retrospectively collected using a standardized electronic database. The primary outcome was time to all-cause mortality or lung transplant. Kaplan Meier analysis was used to evaluate the association of threshold values of baseline FVC and DLCO and survival. Cox proportional hazards models were used to evaluate the adjusted association of FVC and DLCO with mortality or transplantation.

Results:

1200 patients with SSc were screened to identify 188 SSc-ILD patients, 140 (75%) were female, and 69% had never smoked. 55 (29.3%) patients had pulmonary hypertension. The mean±standard deviation (sd) baseline FVC was 78.1%±20.4% predicted, and DLCO was 59.5%±17.9% predicted. The mean (sd) baseline 6-minute walk test distance was 412 (119) meters. 45 (23.9%) patients received immunosuppressive treatment at baseline. 38 (20%) patients died, and five (2.7%) patients underwent lung transplant. Baseline FVC <80% predicted (p=0.003) or DLCO<80% predicted (p=0.01) were associated with mortality. Unadjusted survival analysis found baseline FVC (Hazard Ratio (HR) 0.97 (0.95, 0.98), p <0.001) and DLCO (HR 0.97 (0.96, 0.99), p=0.002) were associated with survival. In the adjusted analysis, FVC (HR 0.93, p=0.007) and smoking history (HR 5.08, p=0.049) were both independently associated with survival, however DLCO (HR 0.98, p=0.33), age (HR 1.00, p=0.77), pulmonary hypertension (HR 1.97, p=0.46), SSc-specific antibodies (HR 0.50, p=0.39), and immunosuppressive use (HR 0.64, p=0.64) were not.

Conclusion: Our study confirms and extends previous findings that even a mild decrease in baseline FVC (< 80%) is predictive of mortality. However, we did not observe a robust association between DLCO and mortality.

Disclosure:

S. M. Shadly,
None;

S. R. Johnson,
None;

C. Chau,
None;

T. K. Marras,
None.

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