PAH Patients with Autoimmune Rheumatic Diseases Not at Higher Risk with Lung Transplant, Study Says

The presence of systemic autoimmune rheumatic diseases (ARDs) — a comorbidity that can range from systemic sclerosis to Sjögren’s syndrome — does not impact survival rates among adults with pulmonary arterial hypertension (PAH) who undergo a lung transplant, a study says.

The report, “Survival of adults with systemic autoimmune rheumatic diseases and pulmonary arterial hypertension after lung transplantation,” was published in the journal Rheumatology, and funded by the Rheumatology Research Foundation and Health Resources & Services Administration.

Even though PAH is a major cause of complications and death in adults with ARDs, patients with ARDs might be denied lung transplants because transplant centers are concerned that the effects of these systemic diseases outside the lungs will reduce a patient’s chances of survival after the transplant.

For example, people with systemic sclerosis — an ARD with a high prevalence of PAH and interstitial lung disease — were seen to have a higher risk of death in the first year post-transplant than patients with interstitial lung disease but no systemic sclerosis.

However, it is unknown if these diseases can impact lung transplant outcomes specifically in PAH patients.

Researchers used United Network for Organ Sharing (UNOS) data from 93 adults with ARDs plus PAH (ARD-PAH) and 222 adults with PAH only, who underwent a single or double lung transplant in the U.S. between 2005 and 2015.

ARDs in these patients included systemic sclerosis (most prevalent, in 68 percent of patients), dermatomyositis/polymyositis (11 percent), mixed connective tissue disease (10 percent), rheumatoid arthritis (3 percent), systemic lupus erythematosus (3 percent), Sjögren’s syndrome (2 percent), or an unspecified connective tissue disease (3 percent).

Patients who received a heart-lung transplant were excluded from the study.

Researchers looked at the association between ARDs and survival up to 11 years post-transplant. Adjustments were made to account for additional variables such as forced vital capacity (FVC; a measure of lung function), lung allocation score (LAS) — used to prioritize candidates on the waiting list based on medical urgency and post-transplant survival  — and corticosteroid use.

Results showed that life expectancy after the transplant was not significantly different between the ARD-PAH group, where estimated rates of mortality were approximately 13 per 100 persons per year, and the PAH group, which was 12 per 100 persons per year.

This shows that the presence of an ARD is not associated with increased mortality after lung transplants in adults with PAH.

Limitations of the study included the rigorous selection processes that participants with ARD-PAH underwent at their transplant centers prior to listing. As a result, the outcomes reported are from carefully selected candidates and might not represent all adults with ARD-PAH, the researchers said.

Nonetheless, the team concluded that “those with ARD-PAH comprise a group in which lung transplantation may be particularly beneficial. Our findings provide support for offering lung transplantation to carefully selected candidates with ARD-PAH.”