High false negative rate with PFTs in scleroderma lung disease

(HealthDay)—Use of pulmonary function tests (PFTs) is associated with high false negative rates for detection of scleroderma-associated interstitial lung disease (SSc-ILD), according to a study published online Aug. 28 in Arthritis & Rheumatology.

Yossra A. Suliman, M.D., from the University Hospital Zurich, and colleagues prospectively enrolled 102 SSc patients who were assessed following EUSTAR standards to compare PFTs and high-resolution computed tomography of the chest (HRCT). Two experienced radiologists blindly evaluated the images.

The researchers found that 63 percent of patients showed significant ILD on HRCT, 26 percent had a forced vital capacity (FVC) <80 percent, and 53 percent had a reduction in one or more PFTs. The false negative rate of FVC was high, with normal FVC in 62.5 percent of patients with significant ILD on HRCT. Six percent of patients with normal FVC had severe, functionally-occult lung fibrosis; two of these patients had all PFTs within normal limits. Compared with ILD-free cases, false negative cases more often had anti-Scl-70 antibodies and diffuse SSc, and less frequently had anti-centromere antibodies (ACA).

"The derived evidence-based data reveal a high risk of missing the detection of significant SSc-ILD when relying solely on PFTs," the authors write. "Particularly, additional imaging investigations should be considered in ACA negative patients with normal FVC for the early detection of SSc-ILD."

Several authors disclosed financial ties to the pharmaceutical industry.

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