Low income linked to more severe chronic thromboembolic pulmonary hypertension

Key takeaways:

• 6-minute walk distances were shorter among patients with chronic thromboembolic pulmonary hypertension and low vs. high median incomes.
• Low socioeconomic status was linked to less improvement in hemodynamics.

HONOLULU — Patients with chronic thromboembolism pulmonary hypertension and a higher median income had better 6-minute walk distance and hemodynamics than those with a low income, according to a presentation at the CHEST Annual Meeting.

“We understand that in various other pulmonary disorders, particularly cystic fibrosis, asthma, COPD ... that a low socioeconomic status is associated with poor outcomes in these patients,” Arsal Tharwani, MD, pulmonary and critical care fellow at Cleveland Clinic Foundation, said during his presentation. “But in literature [we have] a lack of data defining association of socioeconomic status with [chronic thromboembolic pulmonary hypertension].”

In a retrospective observational study, Tharwani and colleague Gustavo A. Heresi, MD, MS, director of the pulmonary vascular and chronic thromboembolic pulmonary hypertension program in the department of pulmonary and critical care medicine at the Cleveland Clinic Respiratory Institute, assessed 352 patients (mean age, 54.5 years; 52.2% men; 74.1% white) diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH) at Cleveland Clinic between 2011 and 2021 to determine whether socioeconomic status is related to disease severity in this patient population.

Researchers used each patient’s residential zip code as a marker of their socioeconomic status. Also, using data from the American Community Survey, researchers grouped patients into four even quartiles based on median household income: less than or equal to $41,110, more than $41,110 to $50,672, more than $50,672 to $64,239, and more than $64,239.

Researchers noted that patients in the higher household income groups tended to be older, with mean ages of 50.9 years in lowest median income group compared with 57.9 years in highest group.

Although nonsignificant, researchers also found that the number of African American patients decreased as socioeconomic status increased, with 42 in the lowest median income group and only 13 in the highest median income group.

BMI, New York Heart Association class and N-terminal prohormone of brain natriuretic peptide appeared comparable across the four income groups.

Notably, those in the lowest income group did significantly differ from those in higher income groups when assessing 6-minute walk distance (≤ $41,110, 278 m; > $41,110 to ≤ $50,672, 316 m; > $50,672 to ≤ $64,239, 319 m; > $64,239, 302 m; P = .0013).

Several right heart catheterization variables also significantly differed by socioeconomic status, and researchers found that cardiac output (P = .005) and cardiac index (P = .0028) by thermodilution each improved as socioeconomic status increased. Use of Fick’s method additionally showed that cardiac output (P = .0016) and cardiac index (P = .0041) significantly differed according to socioeconomic status.

Mixed venous oxygen saturation also went up as the median household income increased (P = .0095).

“The reason why we think that the 6-minute walk distance for these patients may be lower and the severity of outcomes in terms of cardiac output and cardiac index ... worse is because of perhaps delays in diagnosis,” Tharwani said.

“Maybe there is an intrinsic factor here which is associated with high inflammatory burden which is seen in lower socioeconomic status,” he added.

Notably, researchers found no significant differences in right atrial pressure, pulmonary artery pressure, pulmonary thrombendarteriectomy and balloon pulmonary angioplasty across the four levels of socioeconomic status.

Operative mortality among those who underwent pulmonary thromboendoarterectomy was comparable across the income groups, with two deaths each in the lowest and highest categories, four in the more than $50,672 to $64,239 group and none in the more than $41,110 and $50,672 group.

Tharwani also mentioned that long-term survival and hospitalization among the four levels of socioeconomic status did not significantly differ.

“The reason for no difference in survival could be due to therapeutic modalities offered at our institution,” he said during his presentation.

One limitation of the present study was that researchers used zip codes to determine socioeconomic status, which Tharwani noted could be reconsidered in future studies.

“Perhaps socioeconomic index looking at occupation and education of our patients ... may be a better marker,” he said.