RT Journal Article
SR Electronic
T1 Performance of Forced Vital Capacity and Lung Diffusion Cutpoints for Associated Radiographic Interstitial Lung Disease in Systemic Sclerosis
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP jrheum.171362
DO 10.3899/jrheum.171362
A1 Kimberly Showalter
A1 Aileen Hoffmann
A1 Gerald Rouleau
A1 David Aaby
A1 Jungwha Lee
A1 Carrie Richardson
A1 Jane Dematte
A1 Rishi Agrawal
A1 Rowland W.  Chang
A1 Monique Hinchcliff
YR 2018
UL http://www.jrheum.org/content/early/2018/09/24/jrheum.171362.abstract
AB Objective Forced vital capacity (FVC) and DLCO are used for screening of systemic sclerosis–associated interstitial lung disease (SSc-ILD). The study purpose was to determine the sensitivity, specificity, and negative predictive value (NPV) (proportion of true negative screening tests) of FVC and DLCO thresholds for SSc-ILD on chest high-resolution computed tomography (HRCT) scans. Methods Patients fulfilling American College of Rheumatology 2013 SSc criteria with a chest HRCT scan and pulmonary function tests (PFT) were studied. A thoracic radiologist quantified radiographic ILD. Optimal FVC and DLCO % predicted thresholds for ILD were identified using receiver-operating characteristic curves. The FVC and DLCO combinations with greatest sensitivity and specificity were also determined. Subanalysis was performed in patients with positive Scl-70 autoantibodies. Results The study included 265 patients. Of 188 (71%) with radiographic ILD, 59 (31%) had “normal” FVC (≥ 80% predicted), and 65 out of 151 (43%) had “normal” DLCO (≥ 60% predicted). FVC < 80% (sensitivity 0.69, specificity 0.73), and DLCO < 62% (sensitivity 0.60, specificity 0.70) were optimal thresholds for radiographic SSc-ILD. All FVC and DLCO threshold combinations evaluated had NPV < 0.70. The NPV for radiographic ILD for FVC < 80% was lower in patients with positive Scl-70 autoantibody (NPV = 0.05) compared to negative Scl-70 autoantibody (NPV = 0.57). Conclusion Radiographic ILD is prevalent in SSc despite “normal” PFT. No % predicted FVC or DLCO threshold combinations yielded high NPV for SSc-ILD screening. “Normal” FVC and DLCO in patients with SSc, especially those with positive Scl-70 autoantibodies, should not obviate consideration of HRCT for ILD evaluation.