PARIS – The traditional way to assess the status of interstitial lung disease in patients with systemic sclerosis, forced vital capacity, may not be the best way, based on a new analysis of 83 patients enrolled in a scleroderma-treatment trial.
"A structural, physiologic, and patient-oriented composite outcome may be a more comprehensive measure of treatment response" for patients with systemic sclerosis (SSc) and interstitial lung disease, Dr. Elizabeth Volkmann said at the annual European Congress of Rheumatology. "The most robust" association seen in her analysis did not include forced vital capacity (FVC) but instead focused on the Transition Dyspnea Index (TDI), the scleroderma modified Health Assessment Questionnaire Disability Index (HAQ-DI), and quantitative, serial assessment of high-resolution CT (HRCT) images of the patient’s lungs, said Dr. Volkmann, a rheumatologist at the University of California, Los Angeles.
Dr. Elizabeth Volkmann
Although her main goal in this analysis was to identify the best assessment of lung disease in SSc patients enrolled in clinical trials, the findings also have implications for managing patients with SSc, also known as scleroderma, in routine practice, Dr. Volkmann said in an interview.
Many physicians "rely solely on FVC for following patients, and I think this may not be the best measure. Now that we have great imaging options we should use them. And the strongest correlates [in the new analysis] were with the HAQ-DI, a measure of what patients can do, and the TDI, in which patients say how much their disease has progressed. They are both patient oriented and tell you how the patient is doing," Dr. Volkmann said.
"The three were more robust and comprehensive than FVC," which can be influenced by many factors and has a variability of 10%. Dr. Volkmann conceded that the quantitative assessment of annual HRCT scans done in the study is not widely available, but she said that visual assessment of HRCT scans highly correlates with quantitative assessment and hence likely makes a reasonable substitute.
A senior collaborator on the study, Dr. Daniel Furst, said that in his opinion it was premature to completely abandon FVC for assessing SSc patients, but it was clearly useful to add the two patient-oriented questionnaires and HRCT imaging.
"We haven’t discarded FVC, but we’ve added the other things," he said in an interview. "Five years ago we only did FVC, 3 years ago we added the scleroderma HAQ-DI," and now he and his associates also use annual HRCT imaging as well as the TDI. The two questionnaires are administered every 3-6 months, said Dr. Furst, professor of rheumatology at UCLA.
"Using all four of these tools is not being widely done" right now in U.S. rheumatology practice. "I really think it’s a step forward." However, Dr. Furst also cautioned that for adoption into routine practice he would like to see evidence documenting that this approach has a positive impact on patient outcomes.
Dr. Daniel E. Furst
Dr. Volkmann’s analysis involved the 158 U.S. patients enrolled in the first Scleroderma Lung Study, run in 2000-2004 at 13 U.S. centers to compare treatment with oral cyclophosphamide against placebo in patients with active SSC and interstitial lung disease (N. Engl. J. Med. 2006;354:2655-66). Of the 158 patients enrolled, 125 had an HRCT scan at baseline, and among those, 83 also had a HRCT scan after 12 months. These 83 patients formed the basis for Dr. Volkmann’s analysis, including 41 patients randomized to cyclophosphamide treatment and 42 randomized to placebo.
Multivariate analysis identified the HAQ-DI, TDI, FVC, and a quantitative lung fibrosis score derived from analysis of the serial HRCT images as collectively predicting best the outcomes of these patients. A second model that eliminated FVC was "slightly stronger," and both of these combined assessments were each "more robust than FVC alone," Dr. Volkmann said.
Dr. Volkmann said that she had no disclosures. Dr. Furst said that he had no relevant disclosures.
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