PAH Takes Higher Toll on Asian SLE Patients, Study Suggests

In Asian patients with systemic lupus erythematosus, pulmonary arterial hypertension (PAH) is more prevalent and associated with worse overall survival rates than it is for patients in western countries, a study reports.

It also suggests systemic hypertension (high blood pressure) as a risk factor for the development of pulmonary arterial hypertension (PAH). PAH is a devastating disease that affects the respiratory system.

The study, “Incidence and survival impact of pulmonary arterial hypertension among patients with systemic lupus erythematosus: a nationwide cohort study,” was published in the journal Arthritis Research and Therapy.

PAH is a progressive and life-threatening disease, characterized by remodeling and thickening of blood vessels in the lung, potentially leading to blockage of blood flow and severe impairment of the heart.

The condition is often associated with the presence of other diseases, but its incidence and prevalence in patients with systemic lupus erythematosus (SLE) is not fully known, though one  study found that PAH occurs in fewer than 1% of SLE patients.

Because of the low incidence of PAH in SLE patients, the European Respiratory Society does not recommend annual screening for PAH in SLE patients.

Interestingly, the distribution of PAH in Asian countries differs from that of Europe. Recent studies have shown that SLE is the leading cause of PAH in countries such as Japan, Korea, and China.

Thus, “the characteristics and prognosis of Asian SLE patients with PAH may differ from those of patients in Western countries,” researchers said.

However, very few studies have evaluated the incidence of PAH in Asian patients with SLE, leading researchers to investigate the incidence and survival impact of PAH in a cohort of SLE patients.

Researchers used data from a national insurance database in Taiwan, from which they were able to estimate the incidence, determine the impact on survival, and identify risk factors associated with PAH development in SLE.

Among the 15,783 SLE patients in the database, 336 (2.13%) developed PAH a median of 2.8 years after their lupus diagnosis. Most patients (70%) who developed PAH were diagnosed within five years of SLE onset.

When looking at specific risk factors for the development of PAH, researchers found that systemic hypertension (high blood pressure in the systemic arteries, the vessels that carry blood from the heart to the body’s tissue) was an independent predictor of PAH occurrence. In fact, patients with systemic hypertension were 2.3 times more likely to develop PAH compared to patients without systemic hypertension.

Finally, researchers looked at the impact of PAH on the survival of SLE patients. They found that after being diagnosed with PAH, 87.7% patients lived past the one-year mark, and 76.8% lived at least three more years. Five years after the diagnosis, 70.1% of patients were alive.

An additional analysis revealed that those with PAH had a 120% higher risk of death than SLE patients without PAH. Other factors that increased the risk of death in SLE patients were being male, older, and having diabetes, high blood pressure, or chronic disease.

Additionally, the overall survival rate for patients with SLE who develop PAH is worse in Asian countries compared to western countries. However, “the reasons for the difference in survival between western and Asian patients require further investigation,” researchers said.

“The development of PAH in SLE patients is a poor prognostic factor, but systemic hypertension may be a predictive factor for PAH in the SLE population,” investigators concluded.