Systemic hypertension is an independent predictor in rare cases of pulmonary arterial hypertension (PAH) associated with systemic lupus erythematosus (SLE), a retrospective large-cohort study in Taiwan shows.
According to the findings, most of the observed PAH cases occurred within five years of SLE diagnosis.
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 & Therapy.
Systemic lupus erythematosus (SLE) is an autoimmune disease that can affect several organs of the body — particularly the kidneys, heart, and lungs — causing inflammation, pain, and damage to the affected sites. Women have a higher risk of developing SLE than men, and Asians are one of the most commonly affected groups.
The condition can, in rare cases, cause PAH, a severe complication that is one of the most common causes of death among SLE patients. However, the incidence and prevalence of PAH among these patients has not been thoroughly analyzed, although estimates indicate it ranges between 0.5% and 14%, according to the literature.
To increase understanding of SLE-associated PAH, researchers have now evaluated the incidence, possible predictors, and long-term survival of SLE patients with developed PAH in the Taiwanese population.
The study analyzed data from Taiwan’s National Health Insurance Research Database (NHIRD), which includes 99 percent of the country’s population, making it one of the most extensive databases in the world.
Results from the database analysis showed 15,783 individuals with SLE, of whom 336 (2.13%) had developed PAH (mean age of 36.8 at SLE diagnosis). The vast majority of SLE patients were women, making up 91.9% of patients with PAH and 87.2% without PAH.
The three-year incidence of PAH in the SLE population was 1.2% and the five-year incidence was 1.8%. On average, affected patients got diagnosed with PAH 3.66 years after their SLE diagnosis, and most patients (70%) developed PAH within five years after SLE onset.
The team found that SLE patients with systemic hypertension (high arterial blood pressure) were more likely to develop PAH than SLE patients without hypertension. They also found that the increased risk was significant and independent from confounding variables such as age, gender, and other coexisting conditions.
A comparison of mortality risk between patient groups showed that mortality was higher in SLE patients with PAH than in SLE patients without PAH. According to the analyses, SLE patients with PAH had a 120% increased mortality risk, and a five-year survival rate of 70.1%.
Researchers noted that the combined results derived from this study and two others in China and South Korea suggest that Asian patients have “a worse prognosis than the SLE patients in Western countries.” For example, five-year survival rates in SLE patients with PAH were 70.1% in the current study, 72.9% in the Chinese study, and 60.2% in the South Korean study, while two registry studies from France and the U.K. showed five-year survival rates exceeding 80% (83.9% and 85%, respectively).
Due to the worse prognosis in SLE patients with PAH, the team suggests that clinicians monitor PAH-associated symptoms more closely within five years of SLE diagnosis, particularly systemic hypertension, which, according to the findings, was predictive for PAH in SLE patients.
“PAH is a rare complication of SLE, and the majority of PAH cases occur within the first 5 years following SLE diagnosis,” the researchers wrote. “Our findings imply that physicians should have increased awareness of PAH in SLE patients accompanied by systemic hypertension,” they concluded.