Pulmonary arterial hypertension characteristics, mortality vary across US
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Key takeaways:
- The lowest mortality rate after presenting to an accredited center was found in the West with 6.3 deaths per 100 person-years.
- This study serves as a reminder to consider the whole patient.
Among adults with pulmonary arterial hypertension, patient characteristics, mortality and treatment varied across four U.S. census regions, according to results published in Annals of the American Thoracic Society.
“We found differences between regions, which was not at all unexpected,” Peter J. Leary, MD, PhD, director of the pulmonary vascular disease program at the University of Washington, told Healio. “The next steps moving forward will be to try and unpack this regional variation to better understand whether there are modifiable differences that can be addressed to help patients with pulmonary hypertension.”
Using data from the Pulmonary Hypertension Association Registry, Leary and colleagues assessed adults with PAH from the West (n = 445), Midwest (n = 337), South (n = 489) and Northeast (n = 307), who all received care at an expert accredited pulmonary hypertension center and agreed to participate in the registry. The goal was to find regional differences in patient characteristics and disease outcomes.
Patient characteristics
The average age of patients was similar in the Northeast (56.3 years), Midwest (55.3 years) and South (56.3 years) but not in the West (50.5 years).
In terms of race, regions with the highest proportions of white patients included the Northeast (82.7%) and Midwest (80.9%), whereas the highest proportion of Black/African American patients was found in the South (24.4%) and the highest proportion of Asian patients was found in the West (7.9%).
Participants in the West were also the most likely to report Hispanic ethnicity and being born outside the U.S. compared with the other three regions (Hispanic ethnicity, 22.8% vs. 2.4%-6.2%; born outside the U.S., 15.8% vs. 6.6%-8.2%).
Researchers found more married patients in the Midwest (55.7%) and Northeast (54%) relative to the South (47.2%) and the West (40.3%). A similar pattern was observed when evaluating proportions of employed patients across regions, with higher percentages in the Midwest (28.5%) and Northeast (27.7%) compared with the South (25.6%) and West (21.4%).
Private insurance coverage was not reported often in the West (38.7%), whereas over half of patients from the Northeast (59.5%), Midwest (56.1%) and South (53.1%) had this type of coverage.
When evaluating PAH types across regions, researchers observed high percentages of idiopathic/familial PAH in the South (51.9%), Midwest (48.4%) and Northeast (45.6%) but not in the West (30.6%).
In contrast, a high proportion of patients from the West had toxin-mediated PAH (29.4%) compared with the other three regions (3.5%-5.3%).
There was a gradation of self-reported smoking over the previous 30 days that was highest in the West (8.7%) and lowest in the Northeast (3.9%). There was also a gradient in current alcohol use, with the Northeast reporting current use more often (38.8% of participants) and the South reporting current use the least often (26.3%).
The proportion of patients who did not receive a flu or pneumococcal vaccine was largest in the Northeast (flu vaccine, 56% vs. 32.1%-41.1%; pneumococcal vaccine, 64.8% vs. 43.3%-48.8%).
The four regions did not differ from each other in baseline hemodynamic measures, such as right atrial pressure and wedge pressure, according to researchers.
Treatment, disease severity, mortality
It was more common for patients in the West to receive treatment for more than 6 months before being seen in an accredited center (28.9%) and least common in the Midwest (16.8%).
Patients in the registry from the Midwest had the highest proportion of phosphodiesterase 5 inhibitor use (84.1%), followed by the West (81.9%), Northeast (78.5%) and South (72.4%).
Endothelin receptor antagonist use was reported by more patients in the South (59.9%) and Northeast (56.7%) than the West (54.9%) and Midwest (51.2%), according to researchers.
When assessing prostacyclin use, researchers found high percentages of patients using oral prostacyclin in the South (14.3%) and West (10.2%) and high percentages of parenteral prostacyclin use in the other two regions: Midwest (29.4%) and Northeast (25.7%).
Markers of severity on arrival to an accredited center were relatively similar in all four regions, Leary said.
To determine mortality risk in each region, researchers used Kaplan-Meier survival analyses (3,495 person-years; median follow up, 1.9 years) and Cox proportional hazards.
During the follow-up period, 310 patients died. The lowest mortality rate was found in the West at 6.3 deaths per 100 person-years, followed by the Midwest (7.9 deaths per 100 person-years), South and Northeast (both 10.9 deaths per 100 person-years).
Compared with the Northeast, patients in the West had a lower risk for mortality (adjusted HR = 0.6; 95% CI, 0.43-0.83) than patients in the South or Midwest in the model adjusted for age, sex and BMI.
Notably, researchers continued to find this result even after adjusting for multiple covariates (PAH etiology, social determinants of health, disease severity, medications, health behaviors, treatment for more than 6 months and all covariates).
Implications, future research
Although this study does not act as an immediate guide for bedside clinicians, it serves as a basis for further research and a reminder to consider the whole patient, Leary told Healio.
“There were very likely differences in socioeconomic determinants of health, health behaviors and other ‘lifestyle’ focused variation by region,” Leary said. “As such, I think this may be a small piece of the puzzle to reinforce the importance of all the ‘other’ things when caring for patients with PAH. Things like diet, exercise, stress, alcohol or cigarette use all may contribute to the differences in outcomes that we observed.”
Leary said one key limitation of this study was that patients and centers had to volunteer to enter this dataset.
“If possible, it would be ideal to corroborate or refute these observations using a cohort that did not require this extra ‘selection’ step of volunteerism,” Leary said. “Particularly if data aggregation improves across electronic health records, claims data, census data and more, we might be able to better understand whether there are true differences at the patient level rather than regional differences in the willingness of patients or their physicians to participate in research.”
As a final note, Leary added that collaboration between health care teams, researchers, patients, patient advocacy groups and industry/sponsor representatives has propelled advancements in pulmonary vascular disease care.
“It is clear that more work needs to be done, but with ongoing collective effort, I am optimistic about the future,” he said.
For more information:
Peter J. Leary, MD, PhD, can be reached at learyp@uw.edu.