The Predictive Value of Pulmonary Function Tests to Diagnose Interstitial Lung Disease in Adults with Early Diffuse Cutaneous Systemic Sclerosis

Elana J. Bernstein¹, Veronica J. Berrocal², Virginia D. Steen³, Victoria K. Shanmugam^4,5, Ami A. Shah⁶, Monique E. Hinchcliff⁷, Faye N. Hant⁸, Jessica K. Gordon⁹, Tracy M. Frech¹⁰, Robyn T. Domsic¹¹, Shervin Assassi¹² and Dinesh Khanna¹³, ¹Rheumatology, Columbia University College of Physicians & Surgeons, New York, NY, ²Div of Rheumatology, University of Michigan, Ann Arbor, MI, ³Rheumatology, Georgetown University Medical Center, Washington, DC, ⁴Division of Rheumatology, The George Washington University, Washington, DC, ⁵Director, Division of Rheumatology, The George Washington University, Washington, DC, ⁶Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, ⁷Rheumatology, Northwestern University, Chicago, IL, ⁸Dept of Medicine, Medical University of South Carolina, Charleston, SC, ⁹Rheumatology, Hospital for Special Surgery, New York, NY, ¹⁰Div of Rheumatology, University of Utah, Salt Lake City, UT, ¹¹Medicine - Rheumatology, University of Pittsburgh, Pittsburgh, PA, ¹²Rheumatology, University of Texas Medical School at Houston, Houston, TX, ¹³Division of Rheumatology, University of Michigan, Ann Arbor, MI

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: interstitial lung disease, scleroderma and systemic sclerosis

Session Information

Date: Monday, November 9, 2015

Title: Systemic Sclerosis, Fibrosing Syndromes and Raynaud's - Clinical Aspects and Therapeutics Poster II

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Interstitial lung disease (ILD) is the leading cause of death in patients with systemic sclerosis (SSc). Patients with diffuse cutaneous systemic sclerosis (dcSSc) have an increased risk of the development of ILD. High resolution computed tomography of the chest (HRCT) is the radiographic gold standard for the diagnosis of ILD. Pulmonary function testing (PFT) is a common screening method for ILD. However, some SSc patients with entirely normal PFTs have ILD evident on their HRCTs. Our aim was to assess the performance characteristics of PFTs for the diagnosis of ILD in patients with early dcSSc, using HRCT as the reference standard.

Methods: Subjects were enrolled in the Prospective Registry of Early Systemic Sclerosis (PRESS), a multicenter, prospective registry of adults with early dcSSc (disease duration < 2 years from first non-Raynaud’s symptom), between April 2012 and June 2015. Subjects were included in this study if they had baseline PFTs. The presence or absence of ILD on HRCT was determined by chest radiologists at each center. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of forced vital capacity (FVC), total lung capacity (TLC), and diffusion capacity for carbon monoxide (DLCO) for the diagnosis of ILD were calculated. A cut-off point of <80 %predicted was defined as abnormal for each PFT parameter.

Results: The mean age of the 91 subjects with baseline measurements of FVC was 52 years (± 15.3); 68% were female and 74% were white. 54% of the 50 subjects who underwent HRCT had radiographic evidence of ILD (Table 1). DLCO had a higher sensitivity for the diagnosis of ILD than either FVC or TLC alone (Table 2). The combination of FVC and DLCO had a higher sensitivity for the diagnosis of ILD than DLCO alone. However, all PFT parameters (either alone or in combination) had only moderate specificity.

Conclusion: Although the combination of FVC and DLCO had excellent sensitivity for the diagnosis of ILD in early dcSSc, this combination only had moderate specificity for the diagnosis of ILD. Given the increased risk of ILD in patients with dcSSc, it may be reasonable to order an HRCT for all patients newly diagnosed with dcSSc, regardless of PFT results. Future work is needed to develop the optimal screening algorithm for ILD in patients with dcSSc.

Table 1: Baseline Characteristics of Subjects
	N = 91
Age, mean ± SD	52.0 ± 15.3
Female sex, n (%)	62 (68.1)
Race
Black, n (%)	10 (15.3)
White, n (%)	71 (73.7)
ANA positive, n (%)	58/68 (85.3)
Anti-Scl-70 positive, n (%)	22/67 (32.8)
Anti-RNA polymerase III positive, n (%)	34/56 (60.7)
FVC %predicted, mean ± SD	79.9 ± 21.2
TLC %predicted, mean ± SD	84.4 ± 23.8 n = 61
DLCO %predicted, mean ± SD	70.1 ± 25.5 n = 86
ILD on HRCT, n (%)	27/50 (54.0)

Table 2: Performance Characteristics of PFTs with HRCT for the Diagnosis of ILD
Test	N	Sensitivity	Specificity	PPV	NPV
FVC < 80 %predicted	45	56.0%	55.0%	60.9%	50.0%
TLC < 80 %predicted	34	52.9%	70.6%	64.3%	60.0%
DLCO < 80 %predicted	42	86.4%	60.0%	70.4%	80.0%
FVC & DLCO < 80 %predicted	42	90.9%	45.0%	64.5%	81.8%
FVC & DLCO & TLC < 80 %predicted	34	88.2%	47.1%	62.5%	80.0%

Disclosure: E. J. Bernstein, None; V. J. Berrocal, None; V. D. Steen, None; V. K. Shanmugam, None; A. A. Shah, None; M. E. Hinchcliff, None; F. N. Hant, None; J. K. Gordon, Bayer, 5; T. M. Frech, None; R. T. Domsic, Biogen-Idec, 5,Bayer, 5; S. Assassi, None; D. Khanna, Bristol-Myers Squibb, 2,EMD Serono, 2,Genentech and Biogen IDEC Inc., 2,Bayer, 5,Biogen Idec, 5,Cytori, 5,EMD Serono, 5,Forward, 5,Genentech and Biogen IDEC Inc., 5,Gilead, 5,Lycera, 5,Seattle Genetics, 5.

To cite this abstract in AMA style:

Bernstein EJ, Berrocal VJ, Steen VD, Shanmugam VK, Shah AA, Hinchcliff ME, Hant FN, Gordon JK, Frech TM, Domsic RT, Assassi S, Khanna D. The Predictive Value of Pulmonary Function Tests to Diagnose Interstitial Lung Disease in Adults with Early Diffuse Cutaneous Systemic Sclerosis [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/the-predictive-value-of-pulmonary-function-tests-to-diagnose-interstitial-lung-disease-in-adults-with-early-diffuse-cutaneous-systemic-sclerosis/. Accessed .

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