Concurrent PAH-ILD occurs in 7% of patients with systemic sclerosis
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Key takeaways:
- Concurrent pulmonary arterial hypertension and interstitial lung disease occurred in approximately 7% of a systemic sclerosis cohort.
- Researchers noted that the combination has “major” implications for survival and health-related quality of life.
Approximately 7% of patients with systemic sclerosis in an Australian cohort demonstrated concurrent pulmonary arterial hypertension and interstitial lung disease, according to data published in Arthritis Research & Therapy.
The researchers additionally concluded that patients with both pulmonary arterial hypertension (PAH) and ILD had a poorer survival vs. those with either PAH or ILD alone.
“Historically, PAH and ILD have been viewed as independent manifestations of systemic sclerosis — more recently, we have recognized that these complications can occur together more frequently than had previously been thought,” Jessica L. Fairley, MBBS, of the University of Melbourne at St. Vincent’s Hospital, in Australia, and lead study author, told Healio.
“There is thus increasing interest in those individuals who may develop both PAH and ILD — in particular, how often this occurs, who may be affected, and what the impact is on survival and quality of life,” she added. “Accordingly, we performed this study to explore these questions and to better understand this patient group.”
To investigate the relationship between PAH and ILD in SSc, Fairley and colleagues conducted an analysis of patients enrolled in the Australian Scleroderma Cohort Study (ASCS) who were diagnosed with SSc between 2007 and October 2019. Following enrollment, patients were divided into four groups — those who had PAH alone, those with ILD alone, those with both ILD and PAH and those with neither.
Participants were monitored for the development of PAH throughout the study period, while demographic and clinical disease information were collected annually. Disease onset and duration were determined by using the time of first the manifestation of a symptom not related to Raynaud’s syndrome. Patient-reported outcomes were recorded annually, with participants answering questions regarding disease activity and health-related quality of life (HRQoL). Additionally, the researchers measured comorbidity burdens for each patient.
The analysis included 1,561 patients with SSc, of whom 7% had PAH alone, 24% had ILD alone, 7% had both manifestations and 62% had neither. Factors associated with demonstrating concurrent PAH and ILD included male sex, skin involvement, high inflammatory markers, older age at SSc onset and greater ILD frequency (P < .001), according to the researchers. People of Asian descent were more likely to develop both PAH and ILD (P < .001). Survival was reduced in the groups where PAH was present (P < .01).
“While developing either PAH or ILD conferred a worse prognosis than those with scleroderma alone, PAH appeared to have a more dominant impact on survival than ILD,” Fairley said. “In particular, those with PAH and extensive ILD had a more than five-fold increase in mortality in multivariable modeling. All in all, pre-capillary pulmonary hypertension and ILD seem to occur concurrently in around 7% of those with scleroderma, and this combination has major implications for both survival and health-related quality of life.”
Perspective
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Pulmonary involvement is thought to occur in approximately 80% of patients with systemic sclerosis during the course of the disease, and is the leading cause of morbidity and mortality in this population.
Fairley and colleagues describe the characteristics of pulmonary disease in a large Australian study of SSc. The relatively high number of patients who did not have any documented pulmonary disease may be related to high resolution computed tomography not being consistently obtained, which therefore may underestimate mild interstitial lung disease cases. Serological assessments of pulmonary hypertension (PH) such as pro-BNP were not routinely performed. Nevertheless, the close monitoring and longitudinal follow-up of this large cohort is notable.
This study also confirms previous cohorts that reveal pulmonary arterial hypertension (PAH) appears to have the most significant impact on survival. Patients in the Australian study with PAH-ILD or isolated PAH have a significantly worse prognosis than those patients with ILD only. SSc-PAH patients are usually less responsive to treatment than patients with idiopathic PAH and have a worse prognosis. This is likely because precise phenotyping of PH in SSc is a challenge to clinicians, considering the potential overlap in any given patient of pre-capillary arterial vasculopathy (group 1 PH), cardiac involvement (group 2 PH) and lung fibrosis (group 3 PH).
Clinicians remain hopeful that further understanding the heterogeneous PH phenotypes can help refine screening algorithms and guide future therapies that are desperately needed for this devastating disease.
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