Genetic Admixture and Survival in Diverse Populations with Pulmonary Arterial Hypertension

Racial disparities in treatment patterns, healthcare resource use, and outcomes in patients with pulmonary arterial hypertension in the United States

OBJECTIVE

This retrospective study using claims data compared demographics, clinical characteristics, treatment patterns, healthcare resource utilization, and clinical outcomes in Black and White patients with pulmonary arterial hypertension (PAH) in the United States.

METHODS

Patients (aged ≥18 years) had ≥1 pharmacy claim for PAH medication, ≥6 months' continuous healthcare plan enrollment, ≥1 inpatient/outpatient medical claim with a pulmonary hypertension diagnosis ≤6 months before first PAH medication, and race recorded.

RESULTS

This analysis included 836 Black and 2896 White patients. Black patients were younger, with lower levels of education and annual household income, and higher comorbidity scores versus White patients. Only ∼14% of Black and White patients received index combination therapy. Lower adherence to index treatment was observed in Black patients. Although adjusted regression analysis in the overall population showed no differences in outcomes between groups, Black patients <65 years were 36% less likely to receive index combination therapy (odds ratio [OR] 0.64; 95% confidence interval [CI] 0.41-0.99), and 46% less likely to adhere to index treatment (OR 0.54; 95% CI 0.33-0.90). Other disparities included 24% higher all-cause health care resource utilization, 75% higher all-cause costs, and higher risk of clinical composite outcome. Social determinants of health (education, income, health insurance plan) partially mediated these race effects.

CONCLUSIONS

Differences in demographics, clinical characteristics, and treatment patterns between Black and White patients with PAH were observed. Disparities between Black and White patients <65 years were only partially mediated through social determinants of health variables, suggesting other factors may be involved.

Pulmonary hypertension survival and hospitalisations in people living with HIV: a systematic review and meta-analysis

INTRODUCTION

People living with HIV (PLHIV) have a higher risk of developing pulmonary hypertension (PH) with subsequent poorer prognosis. This review aimed to determine the (1) survival outcomes and (2) proportion of emergency department (ED) visits and hospitalisations of PLHIV and PH.

METHODS

We conducted a systematic review and meta-analysis of observational studies reporting survival outcomes for PLHIV and PH. Electronic databases (Medline, EMBASE, PubMed, Web of Science, Global Index Medicus and Cochrane Library), trial registries and conference proceedings were searched until 22 July 2023. We pooled similar measures of effect, assessed apriori subgroups and used meta-regression to determine mortality and associated variables.

RESULTS

5248 studies were identified; 28 studies were included with a total of 5459 PLHIV and PH. The mean survival (95% CI) of PLHIV and PH was 37.4 months (29.9 to 44.8). Participants alive at 1, 2 and 3 years were 85.8% (74.1% to 95.0%), 75.2% (61.9% to 86.7%) and 61.9% (51.8% to 71.6%), respectively. ED visits and hospitalisation rates were 73.3% (32.5% to 99.9%) and 71.2% (42.4% to 94.2%), respectively. More severe disease, measured by echocardiogram, was associated with poorer prognosis (β -0.01, 95% CI -0.02 to 0.00, p=0.009). Survival was higher in high-income countries compared with lower-income countries (β 0.50, 95% CI 0.28 to 0.73, p<0.001) and in Europe compared with the America (β 0.56, 95% CI 0.37 to 0.75, p<0.001).

CONCLUSION

Our study confirms poor prognosis and high healthcare utilisation for PLHIV and PH. Prognosis is associated with country income level, geographic region and PH severity. This highlights the importance of screening in this population.

PROSPERO REGISTRATION NUMBER

CRD42023395023.

Insights Into Differences in Pulmonary Hemodynamics in Hispanic Patients With Pulmonary Arterial Hypertension

Background

Emerging data suggest that Hispanic patients with pulmonary arterial hypertension (PAH) exhibit improved survival rates compared to individuals of other ethnicities with similar baseline hemodynamics. However, the underlying reasons for this survival advantage remain unclear. This study focused on comparing pulmonary hemodynamics in Hispanic and non-Hispanic PAH patients and how these differences may contribute to varied clinical outcomes.

Methods

A retrospective analysis of right heart catheterization data was conducted on a treatment-naive PAH patient cohort from a single center.

Results

Over a 10-year period, a total of 226 PAH patients were identified, of which 138 (61%) were Hispanic and 88 (39%) were non-Hispanic. Hispanic patients presented with lower pulmonary artery pressures, lower pulmonary vascular resistance, and exhibited significantly higher pulmonary arterial compliance (PAc). Hispanic patients had better 5-year survival rates.

Conclusions

This study highlights the importance of exploring phenotypic differences in ethnically diverse PAH cohorts.

Differential drug response in pulmonary arterial hypertension: The potential for precision medicine

Pulmonary arterial hypertension (PAH) is a rare, complex, and deadly cardiopulmonary disease. It is characterized by changes in endothelial cell function and smooth muscle cell proliferation in the pulmonary arteries, causing persistent vasoconstriction, resulting in right heart hypertrophy and failure. There are multiple drug classes specific to PAH treatment, but variation between patients may impact treatment response. A small subset of patients is responsive to pulmonary vasodilators and can be treated with calcium channel blockers, which would be deleterious if prescribed to a typical PAH patient. Little is known about the underlying cause of this important difference in vasoresponsive PAH patients. Sex, race/ethnicity, and pharmacogenomics may also factor into efficacy and safety of PAH-specific drugs. Research has indicated that endothelin receptor antagonists may be more effective in women and there have been some minor differences found in certain races and ethnicities, but these findings are muddled by the impact of socioeconomic factors and a lack of representation of non-White patients in clinical trials. Genetic variants in genes such as CYP3A5, CYP2C9, PTGIS, PTGIR, GNG2, CHST3, and CHST13 may influence the efficacy and safety of certain PAH-specific drugs. PAH research faces many challenges, but there is potential for new methodologies to glean new insights into PAH development and treatment.

Health Care Disparities in Pulmonary Arterial Hypertension

The current approach for the management of pulmonary arterial hypertension (PAH) relies on data gathered from clinical trials and large registries. However, there is concern that minorities including Black, Indigenous, and People of Color are underrepresented in these trials and registries, making current data not generalizable to these groups of patients. Hence, it is important to discuss the significance of race/ethnicity and socioeconomic factors in patients with PAH. Here, we review the current knowledge on health care disparities in PAH. We also propose future steps in the global task of assuring justice and equality in access to pulmonary hypertension health care.

Pathophysiology and pathogenic mechanisms of pulmonary hypertension: role of membrane receptors, ion channels, and Ca2+ signaling

The pulmonary circulation is a low-resistance, low-pressure, and high-compliance system that allows the lungs to receive the entire cardiac output. Pulmonary arterial pressure is a function of cardiac output and pulmonary vascular resistance, and pulmonary vascular resistance is inversely proportional to the fourth power of the intraluminal radius of the pulmonary artery. Therefore, a very small decrease of the pulmonary vascular lumen diameter results in a significant increase in pulmonary vascular resistance and pulmonary arterial pressure. Pulmonary arterial hypertension is a fatal and progressive disease with poor prognosis. Regardless of the initial pathogenic triggers, sustained pulmonary vasoconstriction, concentric vascular remodeling, occlusive intimal lesions, in situ thrombosis, and vascular wall stiffening are the major and direct causes for elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension and other forms of precapillary pulmonary hypertension. In this review, we aim to discuss the basic principles and physiological mechanisms involved in the regulation of lung vascular hemodynamics and pulmonary vascular function, the changes in the pulmonary vasculature that contribute to the increased vascular resistance and arterial pressure, and the pathogenic mechanisms involved in the development and progression of pulmonary hypertension. We focus on reviewing the pathogenic roles of membrane receptors, ion channels, and intracellular Ca2+ signaling in pulmonary vascular smooth muscle cells in the development and progression of pulmonary hypertension.

Prognosis in Hispanic patient population with pulmonary arterial hypertension: An application of common risk stratification models

Pulmonary arterial hypertension (PAH) is a cardiovascular disease with high mortality rate. Current guidelines propose initiation and escalation of PAH-targeted treatment based on a goal-directed approach targeting hemodynamic, functional, and biochemical variables. This approach has been successfully validated in large Caucasian cohorts. However, given the low number of Hispanic patients enrolled in large PAH trials and registries, it is unknown if the same prognostic tools can be applied to this patient population. We analyzed a single-center outpatient cohort that consisted of 135 Hispanic patients diagnosed with PAH. Baseline characteristics were calculated based on COMPERA, COMPERA 2.0 and REVEAL 2.0 risk scores before the initiation of PAH-targeted therapies. The survival rate at 1 year after diagnosis was 88% for the entire cohort. The three established risk scores to predict PAH outcomes yielded similar results with reasonable discrimination of mortality in the different risk strata (all p < 0.001). Hispanic patients with PAH have a high mortality rate. Our analysis suggests that guideline proposed risk assessment at baseline yields important prognostic information in this patient population.

RASA3 is a candidate gene in sickle cell disease-associated pulmonary hypertension and pulmonary arterial hypertension

Pulmonary hypertension (PH) is associated with significant morbidity and mortality. RASA3 is a GTPase activating protein integral to angiogenesis and endothelial barrier function. In this study, we explore the association of RASA3 genetic variation with PH risk in patients with sickle cell disease (SCD)-associated PH and pulmonary arterial hypertension (PAH). Cis-expression quantitative trait loci (eQTL) were queried for RASA3 using whole genome genotype arrays and gene expression profiles derived from peripheral blood mononuclear cells (PBMC) of three SCD cohorts. Genome-wide single nucleotide polymorphisms (SNPs) near or in the RASA3 gene that may associate with lung RASA3 expression were identified, reduced to 9 tagging SNPs for RASA3 and associated with markers of PH. Associations between the top RASA3 SNP and PAH severity were corroborated using data from the PAH Biobank and analyzed based on European or African ancestry (EA, AA). We found that PBMC RASA3 expression was lower in patients with SCD-associated PH as defined by echocardiography and right heart catheterization and was associated with higher mortality. One eQTL for RASA3 (rs9525228) was identified, with the risk allele correlating with PH risk, higher tricuspid regurgitant jet velocity and higher pulmonary vascular resistance in patients with SCD-associated PH. rs9525228 associated with markers of precapillary PH and decreased survival in individuals of EA but not AA. In conclusion, RASA3 is a novel candidate gene in SCD-associated PH and PAH, with RASA3 expression appearing to be protective. Further studies are ongoing to delineate the role of RASA3 in PH.

Long-term impact of add-on sequential triple combination therapy in pulmonary arterial hypertension: real world experience

BACKGROUND

Sequential triple combination therapy is recommended for pulmonary arterial hypertension (PAH) patients who are not at therapeutic goal on dual therapy, but long-term data on efficacy and safety is scarce.

OBJECTIVE

To assess the long-term impact of sequential triple combination therapy in patients with PAH who are not at goal on dual combination therapy.

STUDY DESIGN AND METHODS

We performed a retrospective observational study in a racially/ethnically diverse cohort of consecutive PAH patients on a stable dual therapy regimen who remained in intermediate- or high-risk category and were subsequently initiated on sequential triple combination therapy. We studied interval change in functional, echocardiographic, and hemodynamic parameters, REVEAL 2.0 risk category and ERS/ESC 2022 simplified four-strata risk category. Multivariate logistic regression analysis was performed to identify independent predictors of successful risk reduction (achievement or maintenance of REVEAL 2.0 low-risk category). Kaplan-Meier survival curves were created to assess the effect of risk reduction on survival.

RESULTS

Out of 414 PAH patients seen in our program, 55 patients received add-on sequential triple combination regimen and had follow-up hemodynamic data. The mean age was 57 years, with 85% women. The most common etiology of PAH was idiopathic/heritable (41.8%). Most patients were WHO functional class III (76.4%), and 34.5% of patients were in high-risk category (REVEAL 2.0). On a median follow-up of 68 weeks, there was a significant improvement in WHO Functional Class (p < 0.001), six-minute walk distance (35 m) with 61.8% of patients achieving low-risk status by REVEAL 2.0, and a 28% of patients' improvement in pulmonary vascular resistance. Female gender was identified as a strong predictor of successful risk reduction, whereas Hispanic ethnicity estimated right atrial pressure on echocardiogram and pericardial effusion predicted lower probability of risk reduction. Patients who achieved or maintained low-risk status had significantly improved survival.

CONCLUSION

Add-on sequential triple combination therapy significantly increased functional, echocardiographic, and hemodynamic parameters with improvement in risk category and survival.

Social determinants of health in pulmonary arterial hypertension patients in the United States: Clinician perspective and health policy implications

Social determinants of health (SDoH) can impact the vulnerable pulmonary arterial hypertension (PAH) population, especially during the COVID-19 pandemic. Providers' understanding of SDoH at the point of care and their impact is unknown. We conducted semi-structured virtual interviews with US clinicians at 17 pulmonary hypertension (PH) centers and one patient advocate from the Pulmonary Hypertension Association. We sought participants' perspective on SDoH in PAH and their impact. Transcripts were developed and analyzed for key themes to assess potential policy implications. Participants served a large PAH population and demonstrated high awareness of SDoH and its impact on treatment and outcomes. They reported that patients' SDoH, including socioeconomic status, health insurance, access to health care, education levels, health literacy, employment status, and insecurities associated with housing, food, transportation, and family support, impacted health and well-being. COVID-19-related social isolation, mental health, and substance abuse contributed to significant inequities in care provision and outcomes. While telemedicine helped clinicians manage patients remotely during the pandemic, there was a concern for patients with limited access to this medium. Participants reported no formal screening for SDoH at the point of care. With the recognition and the desire to act upon health inequities associated with SDoH, participants felt that it was vital for their centers to have a dedicated PH social worker and support staff to optimize care and outcomes. An approach that integrates SDoH in PAH care management, streamlined through institutional policy, could address health disparities leading to improved healthcare access, outcomes, and quality of care.

Hispanic Ethnicity and Social Determinants of Health in Pulmonary Arterial Hypertension: The Pulmonary Hypertension Association Registry

Rationale There is a noticeable underrepresentation of minorities in clinical trials and registries in pulmonary arterial hypertension (PAH). Prior studies evaluating the association between Hispanic ethnicity and clinical outcomes in patients with PAH have not assessed the socioeconomic profile of Hispanic individuals or the significance of social determinants of health in clinical outcomes. Objective To determine the association between Hispanic ethnicity, social determinants of health, and clinical outcomes in PAH. Methods Prospective cohort study of adult participants with PAH enrolled in the Pulmonary Hypertension Association Registry, a multicenter US-based registry of patients treated at Pulmonary Hypertension Care Centers. Participants were classified as Hispanics and non-Hispanic Whites, based on self-reported ethnicity. A comparison of baseline clinical and sociodemographic characteristics between groups was performed as well using absolute standardized differences (ASD). The primary outcome of the study was to assess transplant-free survival between Hispanics and non-Hispanic Whites. A Cox proportional hazards model was used for the multivariable analysis after adjusting for age, sex, PAH etiology, annual income, education level and health insurance. Results A total of 683 individuals were included, 98 (14.3%) of Hispanic ethnicity. Hispanic patients had impaired access to health care (31.6% vs. 12.9% Medicaid/uninsured; ASD 0.35), lower education level (72.6% vs. 94.0% high school graduates or higher; ASD 0.60) and lower annual income (32.0% vs. 17.4% with income <20,000 US dollars; ASD 0.47), as compared with non-Hispanic Whites. Hispanic patients had a higher frequency of ER visits and a higher number of hospitalizations, despite having similar disease severity (incidence rate ratio 1.452, 95% CI 1.326 - 1.590 and 1.428, 95% CI 1.292 - 1.577, respectively). While the unadjusted analysis showed a lower transplant/death hazard ratio for Hispanics (HR 0.47, 95% CI 0.24-0.94; p=0.032), there was no association between Hispanic ethnicity and outcome in the multivariable model after adjusting for social determinants of health and other covariates (HR 0.76, 95% CI 0.35-1.62; p=0.474). Conclusions Hispanic ethnicity was not associated with differences in survival after adjusting for social determinants of health and other factors. Social determinants of health are important to consider when assessing the association between ethnicity and outcomes in PAH.

The Evolution of Risk Assessment in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a chronic debilitating disease that carries an unacceptably high morbidity and mortality rate despite improved survival with modern therapies. The combination of several modifiable and nonmodifiable variables yields a robust risk assessment across various available clinical calculators. The role of risk calculation is integral to managing PAH and aids in the timely referral to expert centers and potentially lung transplantation. Studies are ongoing to determine the role of risk calculators in the framework of clinical trials and to elucidate novel markers of high risk in PAH.