HRCT Predictors Of Decline In FVC% predicted—Implications For Cohort Enrichment For Scleroderma Lung Disease (SLD) Trials

Dinesh Khanna¹, Chi-hong Tseng², Robert D. Suh³, Fereidoun Abtin⁴, Athol U. Wells⁵, Donald Tashkin⁶ and Jonathan Goldin⁷, ¹University of Michigan, Ann Arbor, MI, ²Medicine, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA, ³UCLA Department of Radiological Sciences, Ronald Reagan UCLA Medical Center, Los Angeles, CA, ⁴Radiology, University of California Los Angeles Medical Center, Santa Monica, CA, ⁵Royal Brompton and Harefield NHS Foundation Trust, Department of Radiology, London, United Kingdom, ⁶Medicine, University of California at Los Angeles, Los Angeles, CA, ⁷Radiology, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, CA

Meeting: 2013 ACR/ARHP Annual Meeting

Keywords: Systemic sclerosis

Session Information

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

Session Type: Abstract Submissions (ACR)

Background/Purpose: Moderate-to-severe HRCT-defined lung involvement (total lung involvement or fibrosis) is a predictor of decline in FVC% predicted and mortality in SLD. Various staging systems have been proposed to evaluate lung involvement in SLD: 1. Visual read of maximum fibrosis score (MaxFib) calculated from the zone with the worst extent of abnormality (maximum score), 2. Goh and Wells scoring system of limited vs. extensive disease (visual read of HRCT for total lung involvement of >20% vs. < 20% and incorporation of FVC% predicted of >70% or < 70%, if indeterminate HRCT read), and 3. computer-aided diagnosis (CAD) of quantitative scoring for percentage with fibrosis (QLF) and total lung involvement (QILD) Our objective was to evaluate the performance of different staging systems in the placebo cohort of SLS-I over 1-year period.

Methods: QLF and QILD were assessed using the CAD and maximum fibrosis score (MaxFib) was calculated from the zone with the worst extent of abnormality (maximum score) based on average of 2 thoracic radiologists. 3 thoracic radiologists read the baseline HRCTs from the SLS-I for total lung involvement (as proposed by Goh and Wells) and read by 5% increments and for indeterminate results (15-25% lung involvement), FVC% was used to classify patients into limited vs. extensive disease. Paired t-test was used to assess for statistical significance for change in FVC% predicted (relative change) over 1-year.

Results: 79 patients were randomized to placebo group; 55 completed the 1-year study. Of these, 48 had FVC% data at baseline and 12 months and good quality HRCT and were included in the analysis. 60% of patients had MaxFib of >25%, 66% were classified as extensive disease, 11% and 79% had >20% QLF and QILD, respectively. Greater cut off for each staging system was associated with greater decline in FVC% predicted at 1-year (Table).

Conclusion: HRCT-defined lung involvement is a predictor of decline in FVC% predicted over 1 year using different staging systems. The choice of system incorporated in a trial depends on the feasibility and available expertise.

Decline in FVC% predicted, Mean (SD)

P value

HRCT Fibrosis score

0-25%

26-100%

1.1 (14.2)

-9.6 (12.5)

.009

Limited disease

Extensive disease

2 .0(15)

-9.0 (12)

.009

Whole QILD

< 20%

>20%

-0.03 (8.08)

-6.8 (15.3)

.07

Whole QLF

< 20%

>20%

-4.2 (13.8)

-15.4 (15.4)

.09

Disclosure:

D. Khanna,

NIH, Scleroderma Fdn,

Actelion, BMS, Merck, DIGNA, Bayer, Gilead, United Therapeutics, Roche,

C. H. Tseng,
None;

R. D. Suh,
None;

F. Abtin,
None;

A. U. Wells,
None;

D. Tashkin,
None;

J. Goldin,
None.

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