PT - JOURNAL ARTICLE AU - Kimberly Showalter AU - Aileen Hoffmann AU - Gerald Rouleau AU - David Aaby AU - Jungwha Lee AU - Carrie Richardson AU - Jane Dematte AU - Rishi Agrawal AU - Rowland W. Chang AU - Monique Hinchcliff TI - Performance of Forced Vital Capacity and Lung Diffusion Cutpoints for Associated Radiographic Interstitial Lung Disease in Systemic Sclerosis AID - 10.3899/jrheum.171362 DP - 2018 Oct 01 TA - The Journal of Rheumatology PG - jrheum.171362 4099 - http://www.jrheum.org/content/early/2018/09/24/jrheum.171362.short 4100 - http://www.jrheum.org/content/early/2018/09/24/jrheum.171362.full 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.