IPF Hospitalizations Linked to 8 Times Higher Mortality Risk
People with idiopathic pulmonary fibrosis (IPF) have an eight times higher risk of mortality during hospitalizations or within three months of being discharged than outside this time window, a U.S. study has found.
The risks were even greater for patients who were admitted to the hospital for a respiratory cause, or who received ventilatory support, meaning they were kept on a machine to help with breathing.
“What we need to do is figure out why these patients are hospitalized and how we can prevent it,” Hyun Kim, MD, associate professor at the University of Minnesota Medical School and the study’s first author, said in a podcast discussing data from a patient registry on which the study was based.
“This is a field that could benefit from a lot more research and study,” Kim said.
The findings were reported in “Hospitalizations in patients with idiopathic pulmonary fibrosis,” a study published in the journal Respiratory Research.
Hospitalizations are common among IPF patients, but their impact on disease outcomes is still unclear.
To study this, a team of U.S. researchers used data from the observational IPF-PRO Registry (NCT01915511), a collection of records from 46 centers across the U.S. on the strategies to diagnose, treat, and manage IPF.
“Observational registries provide the opportunity to investigate the risk and impact of hospitalizations in clinical practice” — essentially, using real-world data — the researchers wrote.
Among the 1,002 patients so far included in the registry, 568 (56.7%) were admitted to the hospital at least once over a period of up to 67 months, or about 5.6 years. Of these, 319 (56.2%) had at least one respiratory-related hospitalization and 120 (21.1%) required ventilatory support.
In line with previous findings, a greater proportion of the individuals who were hospitalized at least once were former smokers and patients using oxygen therapy.
The median duration of the first hospitalization was four days. For those whose first hospitalization had a respiratory cause, the median hospital stay was six days. Those who received ventilatory support during their first hospitalization stayed a median of four days longer in the hospital, up to a maximum of 18 days (more than two weeks).
“There were some characteristics at enrollment that associated with an increased risk of respiratory-related hospitalizations,” Kim said.
These characteristics included being younger — specifically, under age 62 — having a lower body mass index, and having a history of pulmonary hypertension. Individuals with poorer lung function, evidenced by a lower percent predicted forced vital capacity, and those needing at-rest oxygen also have an increased risk of respiratory-related hospital stays, she said.
“Patients using oxygen at rest at enrollment were almost three times as likely to undergo a respiratory-related hospitalization during the follow-up period,” Kim added.
Although acute exacerbations, or flare-ups, are linked to poorer disease outcomes, the researchers said they were “unable to determine which hospitalizations were due to acute exacerbations of IPF or respiratory infections.”
When the team looked at the proportion of patients who had died at year five of follow-up, they found that it was 30.8% among those who had at least one hospitalization and 18.0% among non-hospitalized patients.
According to a statistical model that takes into account multiple variables, patients had an eight times higher risk of mortality during a hospital stay or within 90 days (about three months) of being discharged, compared with periods outside this time window.
For patients with a respiratory-related hospitalization, the risk of mortality was even greater, about 10 times higher, the data showed. Moreover, for those who received ventilatory support while being hospitalized, the risk was 13-fold higher.
“The risk of mortality during hospitalization or within 90 days following discharge was high, particularly among patients who were hospitalized for a respiratory cause or who received ventilatory support,” the researchers concluded.
In one “interesting” but not necessarily surprising finding, according to Kim, the data showed that patients younger than 62 are more likely to be hospitalized than older individuals with IPF. Additionally, the data shows that those under the age of 60 may face the highest risks, Kim said.
“The youngest patients in the registry were at the greatest risk of death or lung transplant,” she said.
Researchers don’t know the reason for those findings, according to Kim, who said “there is a gap in our understanding” that needs to be addressed with further study.
The IPF-PRO Registry, which was launched in June 2014, is sponsored by Duke University and funded in part by Boehringer Ingelheim. It is slated to run through January 2025.
The registry is still recruiting patients ages 30 and older. More information can be found here.