Outcomes Poorer for PH-COPD Than Idiopathic PAH, Registry Data Show
Patients whose pulmonary hypertension is associated with chronic obstructive pulmonary disease (PH-COPD) have a worse clinical status and a poorer outcome than those with idiopathic pulmonary arterial hypertension (IPAH), a study based on real-world data from the COMPERA registry reports.
Although PH is typically mild to moderate in COPD, some patients develop severe PH. According to the study, targeted PAH therapies might improve the clinical status of this particular group of patients.
The study, “Pulmonary hypertension in patients with chronic obstructive lung disease: results from COMPERA,” was published in the journal CHEST.
COMPERA and COMPERA-KIDS (NCT01347216) is an ongoing European registry that was launched for adults in 2007 and extended to children in 2013. As of August 2020, it has captured data on more than 10,100 patients of all age groups with any form of PH or PAH.
Although PH occurs in around half of patients with COPD, only a handful of studies have looked at the benefits of using medications developed to specifically treat PAH in PH-COPD, with mixed results.
“Even though the role of PH therapy in patients with PH-COPD remains undefined, PAH therapies are sometimes used in these patients,” the researchers wrote.
To provide more insight into this matter, an international team of researchers examined the medical records of 375 adults with PH-COPD (68 with moderate PH-COPD, and 307 with severe PH-COPD) and 489 patients with IPAH from the COMPERA registry.
Patients with PH-COPD were predominantly men (59%), and were older (mean age, 68.4) than patients with IPAH (mean age, 61.7). Despite similar blood flow parameters, PH-COPD patients also had more severe airflow obstruction, shorter walking distance on a flat, hard surface in six minutes (6MWD, a measure that reflects the person’s exercise capacity and endurance), and worse World Health Organization (WHO) functional class (a measure of how severe a person’s PH symptoms are) than those with IPAH.
Another difference was related to the type of medication: while the majority (92%) of people with PH-COPD were initially treated with monotherapy based on phosphodiesterase-5 inhibitors — molecules that act to widen the blood vessels, leading to an increase in blood flow — only 52% of patients with IPAH received phosphodiesterase-5 inhibitors as a sole therapy.
Transplant-free survival rates at one, three, and five years were lower in the group of PH-COPD patients (86%, 55%, and 38%, respectively) than in the group of patients with IPAH (94%, 74%, and 57%, respectively).
In total, 161 people (45.7%) in the PH-COPD group and 102 (24.9%) in the IPAH group died over the course of the study.
Among those with PH-COPD, being a man, covering a shorter 6MWD, and having increased pulmonary vascular resistance were risk factors associated with a poorer outcome.
Patients with severe PH-COPD were also at a higher risk of death. “The mortality rate was around 12% per year in patients with severe PH-COPD, i.e., about twice the observed mortality rate in our IPAH population,” the researchers wrote.
However, some people with severe PH-COPD showed a clinical response to targeted therapies. In these patients, functional improvements seen after initiation of medication, namely an increase in the 6MWD equal to or greater than 30 meters or an improvement in the WHO functional class, were associated with better outcomes.
“Our data raise the possibility that some patients with severe PH-COPD may benefit from treatment with PAH medications,” the researchers wrote.
Nonetheless, the data must be interpreted with caution, they emphasized.
“Our data do not provide evidence that PH drugs are beneficial in patients with PH-COPD and they are not intended to encourage physicians to use these drugs outside the setting of clinical trials,” the researchers wrote. “Randomized, controlled studies are necessary to further explore this hypothesis.”