Key Risk Factors for Interstitial Lung Disease in Rheumatic Diseases

While immunosuppressive therapies remain a cornerstone of treatment, they come with challenges, including an increased risk of infections. Therefore, recent advancements in clinical trials and guidelines are helping to refine treatment strategies, says Anna-Maria Hoffmann-Vold, MD, PhD, a senior consultant and leader of inflammatory and fibrotic research area at Oslo University Hospital.

Transcript

What are the key risk factors for developing interstitial lung disease (ILD) in patients with rheumatic diseases, and how do they vary between different rheumatic conditions?

I think the first point to understand is that the prevalence of interstitial lung disease varies across the different rheumatic diseases. So, a main risk factor is the underlying rheumatic disease. If a patient has antisynthetase syndrome, the likelihood of having ILD is very high. So, antisynthetase syndrome is a risk factor, and then there are different autoantibodies. The presence of different autoantibodies are a risk factor for ILD. Anti-synthetase syndrome, for example, MDA5 [and] Jo-1, are risk factors for having or developing ILD. The same is also true for other rheumatic diseases, especially these different autoantibodies. So, we know, for example, that for systemic sclerosis, the presence of anti–topoisomerase 1 antibody is a risk factor for ILD. And this is true for every rheumatic disease, depending on the underlying disease.

Then we have general risk factors. So, we often know that despite being predominantly female, male gender is a risk factor for developing ILD across the different rheumatic diseases. Then we know RA-ILD, so rheumatoid arthritis, is a bit special. Then we know that active joint disease is a risk factor for interstitial lung disease. We know also that smoking [and] other diseases have different risk factors. So, it varies, but [there are] some general and some specific ones.

What are the most effective diagnostic tools or biomarkers for early detection of ILD in patients with rheumatic conditions, especially in those at high risk?

It's very important that the same is true for interstitial lung disease in rheumatic diseases, as for any interstitial lung disease. The diagnosis needs to be made by HRCT [high-resolution computed tomography]. We would always need an HRCT to know whether a patient has interstitial lung disease.

In addition, of course, as for other interstitial lung disease, we do want a lung function test to know the baseline values for FVC [forced vital lung capacity], FEV₁ [forced expiratory volume per 1 second], and DLco [diffusing capacity of the lungs for carbon monoxide]. Next to the structural changes on HRCT, the functional values of lung function test, we would also always want to know respiratory symptoms, exercise capacities such as the 6-minute walking test [and] desaturation on the 6-minute walking test. These are diagnostic tools.

For rheumatic diseases, if we think from a rheumatology point of view, we would always need to know which patient to screen for ILD. And of course, we use the same tools such as HRCT for screening, but we would need to know what kind of rheumatic disease it is. For systemic cirrhosis, mixed connective tissue disease, antisynthetase syndrome, these patients have a high prevalence of interstitial lung disease. So, it makes sense to do an HRCT in all these patients compared to rheumatoid arthritis or Sjögren [syndrome], where a smaller subgroup of patients develops interstitial lung disease [where] makes sense to have a risk factor-based approach. So, knowing how many risk factors a patient has for interstitial lung disease, and then screening these patients, but not all patients. So again, it really depends on the underlying rheumatic disease.