ILD may appear years after other symptoms of scleroderma: Study
Late-onset ILD similar to earlier presentation in severity, progression
Interstitial lung disease (ILD), a condition in which scarring damages lung tissue and makes breathing difficult, may appear several years after other symptoms of scleroderma (SSc) start, a study reported.
Late-onset ILD in SSc was similar lung in severity and progression to the early-onset presentation. “Surveillance for incident ILD should continue even in patients with longstanding SSc especially in the presence of risk factors, as patients may be equally at risk of having progressive disease regardless of disease duration at time of ILD onset,” the scientists wrote.
The study, “Characterisation of incident interstitial lung disease in late systemic sclerosis,” was published in Arthritis & Rheumatology.
ILD is the leading cause of death in people with SSc. It often develops within the first three to five years of the first non-Raynaud’s manifestation, which has made most clinical trials in SSc-ILD exclude participants who are beyond seven years of SSc onset. Raynaud’s phenomenon causes pain and tingling in the hands and fingers in response to cold temperatures or stress.
But ILD may also develop in people with more longstanding SSc, with data showing similar ILD progression regardless of SSc duration, as well as effective immunosuppression treatment in late SSc-ILD.
ILD and symptoms of scleroderma
Researchers in Canada compared the development, characteristics, risk factors and treatment outcomes of cases in which ILD appeared earlier vs. later in SSc. Participants had enrolled in the Canadian Scleroderma Research Group from 2004 to 2020. Of the 969 patients enrolled, 199 (21%) developed ILD during a median follow-up of 2.4 years. In this group, 131 patients (66%) had ILD diagnosed at least seven years after the first non-Raynaud’s SSc manifestation.
The incidence rate (a measure of the number of new cases) for this late-onset group was 3.7 per 100 person-years, lower than in the earlier-onset group (5.4 per 100 person-years). Person-years is a measure that accounts for the total number of patients and the amount of time each person spent in a study.
Risk factors for developing ILD later in SSc generally matched those in earlier-onset disease and included being male, having diffuse skin lesions, myositis (muscle inflammation), or anti-topoisomerase I antibodies (self-reactive antibodies associated with SSc). Higher levels of C-reactive protein, an inflammation marker, were also associated with late-onset ILD.
People with late-onset ILD were less frequently white than those whose ILD developed earlier. They more frequently had arthritis (inflammation of the joints) and another type of self-reactive antibody, anti-RNA polymerase III. Lung disease severity, as assessed by standard pulmonary function assessments, was similar between late- and earlier-onset SSc-ILD.
ILD progression was equally frequent in early- and late-onset SSc-ILD.
The study’s findings reinforce the importance of monitoring all SSc patients for ILD, even those with longstanding disease, the researchers wrote. “Frequency and modality of monitoring remain to be defined and should be the topic of future research,” they wrote.
“In this multicentric retrospective cohort study, we confirmed that ILD can present in late SSc,” the researchers wrote. “Risk factors for developing ILD in late SSc were largely similar to those observed in earlier SSc.”
Among the study’s limitations, the team noted, was the fact that almost half of the participants were excluded from ILD progression analyses due to missing lung-function test results on follow-up.
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