Prevalence of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in the United States

Economic Burden Associated with Pulmonary Arterial Hypertension in the United States

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pressure in the pulmonary arteries, commonly resulting in right heart failure. PAH is associated with a high economic burden throughout the duration of the disease.

METHODS

This retrospective cohort study of the Milliman Contributor Health Source Data, the Medicare 100% Research Identifiable Files, and the Merative Marketscan® Commercial dataset between 2018 and 2020 identified adult patients with prevalent PAH based on the earliest qualifying diagnosis date or medication date ('index date') between January 1, 2019 and November 30, 2020. Outcomes were assessed using patient data from index date through the earliest of end of enrollment, end of data, or death (Medicare fee-for-service [FFS] only). All-cause and PAH-related medical and pharmacy costs per-patient per-month (PPPM) and healthcare resource utilization per 1000 patients were summarized.

RESULTS

The study included 11,670 Medicare FFS, 1021 Medicare Advantage, 274 Medicaid, and 1174 commercially insured patients in the US. The annual national burden to payers was estimated to be US$3.1 billion. The PPPM payer costs ranged from US$6500 to US$14,742; out-of-pocket (OOP) costs ranged from US$341 to US$907 PPPM. Inpatient utilization rate ranged from 435 to 770 per 1000 patients for all-cause admissions and from 15 to 58 per 1000 patients for PAH-related admissions.

CONCLUSIONS

This study demonstrates that PAH continues to be associated with a high economic burden and healthcare resource utilization across all payer types within the US healthcare system.

Excess healthcare resource utilization and costs for commercially insured patients with pulmonary arterial hypertension: A real-world data analysis

This retrospective study was conducted to evaluate all-cause healthcare resource utilization (HCRU) and costs in commercially insured patients living with pulmonary arterial hypertension (PAH) and explore end-of-life (EOL)-related HCRU and costs. Data from the IQVIA PharMetrics® Plus database (October 2014 to May 2020) were analyzed to identify adults (≥18 years) with PAH (PAH cohort) and those without PH (non-PH cohort). Patients were required to have data for ≥12 months before (baseline) and ≥6 months after (follow-up) the first observed PH diagnosis (index date) for PAH cohort or pseudo index date for non-PH cohort. A PAH EOL cohort was similarly constructed using a broader data window (October 2014 to March 2022) and ≥1 month of follow-up. Annualized all-cause HCRU and costs during follow-up were compared between PAH and non-PH cohorts after 1:1 matching on propensity scores derived from patient characteristics. EOL-related HCRU and costs were explored within 30 days and 6 months before the death date and estimated by a claims-based algorithm in PAH EOL cohort. The annual all-cause total ($183,616 vs. $20,212) and pharmacy ($115,926 vs. $7862; both p < 0.001) costs were 8 and 14 times higher, respectively, in the PAH cohort versus matched non-PH cohort (N = 386 for each). In PAH EOL cohort (N = 28), the mean EOL-related costs were $48,846 and $167,524 per patient within 30 days and 6 months before the estimated death, respectively. Hospitalizations contributed 58.8%-70.8% of the EOL-related costs. The study findings indicate substantial HCRU and costs for PAH. While pharmacy costs were one of the major sources, hospitalization was the primary driver for EOL-related costs.

Population Health Model Predicting the Long-Term Impact of Sotatercept on Morbidity and Mortality in Patients with Pulmonary Arterial Hypertension (PAH)

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare, progressive disease associated with significant morbidity and mortality. The phase 3 STELLAR trial tested sotatercept plus background therapy (BGT) versus placebo plus BGT. BGT was comprised of mono-, double-, or triple-PAH targeted therapy. Building on STELLAR findings, we employed a population health model to assess the potential long-term clinical impact of sotatercept.

METHODS

Based on the well-established ESC/ERS 4-strata risk assessment approach, we developed a six-state Markov-type model (low risk, intermediate-low risk, intermediate-high risk, high risk, lung/heart-lung transplant, and death) to compare the clinical outcomes of sotatercept plus BGT versus BGT alone over a lifetime horizon. State-transition probabilities were obtained from STELLAR. Risk stratum-adjusted mortality and lung/heart-lung transplant probabilities were based on COMPERA PAH registry data, and the post-transplant mortality probability was obtained from existing literature. Model outcomes were discounted at 3% annually. Sensitivity analyses were conducted to examine model robustness.

RESULTS

In the base case, sotatercept plus BGT was associated with longer life expectancy from model baseline (16.5 vs 5.1 years) versus BGT alone, leading to 11.5 years gained per patient. Compared with BGT alone, sotatercept plus BGT was further associated with a gain in infused prostacyclin-free life years per patient, along with 683 PAH hospitalizations and 4 lung/heart-lung transplant avoided per 1000 patients.

CONCLUSIONS

According to this model, adding sotatercept to BGT increased life expectancy by roughly threefold among patients with PAH while reducing utilization of infused prostacyclin, PAH hospitalizations, and lung/heart-lung transplants. Real-world data are needed to confirm these findings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04576988 (STELLAR).

Extracellular Vesicles in Pulmonary Hypertension: A Dangerous Liaison?

The term pulmonary hypertension (PH) refers to different conditions, all characterized by increased pressure and resistance in the pulmonary arterial bed. PH has a wide range of causes (essentially, cardiovascular, pulmonary, or connective tissue disorders); however, idiopathic (i.e., without a clear cause) PH exists. This chronic, progressive, and sometimes devastating disease can finally lead to right heart failure and eventually death, through pulmonary vascular remodeling and dysfunction. The exact nature of PH pathophysiology is sometimes still unclear. Extracellular vesicles (EVs), previously known as apoptotic bodies, microvesicles, and exosomes, are small membrane-bound vesicles that are generated by almost all cell types and can be detected in a variety of physiological fluids. EVs are involved in intercellular communication, thus influencing immunological response, inflammation, embryogenesis, aging, and regenerative processes. Indeed, they transport chemokines, cytokines, lipids, RNA and miRNA, and other biologically active molecules. Although the precise functions of EVs are still not fully known, there is mounting evidence that they can play a significant role in the pathophysiology of PH. In this review, after briefly recapping the key stages of PH pathogenesis, we discuss the current evidence on the functions of EVs both as PH biomarkers and potential participants in the distinct pathways of disease progression.

Inhaled treprostinil vs iloprost: Comparison of adherence, persistence, and health care resource utilization in patients with pulmonary arterial hypertension

BACKGROUND: Pulmonary arterial hypertension (PAH) is associated with a substantial clinical and economic burden. Inhaled prostacyclins are a well-established part of pharmacotherapy for PAH. There are differences between inhaled therapies in the burden imposed by administration frequency. Simpler and less time-consuming inhaled PAH therapies may improve both adherence and persistence and potentially affect outcomes. OBJECTIVE: To compare real-world health care resource use, costs, and treatment adherence and persistence in patients with PAH who initiated inhaled treprostinil or iloprost. METHODS: Adult patients with 1 inpatient or 2 outpatient medical claims separated by at least 30 days with a diagnosis of PAH were identified using International Classification of Diseases, Ninth Revision or Tenth Revision, Clinical Modification codes with a pharmacy claim for inhaled treprostinil or iloprost. Patients were required to be continuously enrolled in the health plan for 6 months prior to and 12 months after the index date. A proportion of days covered of 0.8 or more was considered adherent; persistence was no gap in therapy for at least 60 days. All-cause health care resource utilization and all-cause costs were assessed. RESULTS: 405 and 62 patients were included in the inhaled treprostinil and iloprost cohorts, respectively. Adherence (50.9% and 22.6%; P < 0.0001) and persistence (6 months, 65.2% vs 35.5%; 12 months, 46.7% vs 16.1%; log-rank P < 0.001) were significantly better with inhaled treprostinil. Post-index allcause inpatient admissions (39.3% vs 54.8%; P = 0.02) and post-index emergency department (ED) utilization (36.3% vs 50.0%; P = 0.04) were lower with inhaled treprostinil. Among patients who were persistent with therapy through 12 months, there was no significant difference between groups in mean (SD) all-cause total costs ($266,462 [137,324] vs $262,826 [112,452] for inhaled treprostinil vs iloprost, respectively; P = 0.98). CONCLUSIONS: The results suggest that inhaled treprostinil is less burdensome, is associated with greater adherence and persistence, and may reduce all-cause hospitalizations and ED visits. DISCLOSURES: This study was funded by the United Therapeutics Corporation to obtain data for this analysis and compose the manuscript. Dr Burger has served as clinical investigator in multicenter interventional trials sponsored by United Therapeutics but did not receive any direct compensation. Drs Wu and Morland and Mr Classi are employees of United Therapeutics Corporation and own stock/shares in the company.

Hospitalization-related costs associated with oral agents targeting the prostacyclin pathway for pulmonary arterial hypertension

AIMS

Pulmonary arterial hypertension (PAH) is a rare, progressive, and ultimately fatal form of the broader condition pulmonary hypertension. ESC/ERS guidelines recommend therapy targeting the prostacyclin pathway for patients not achieving low-risk mortality status. Currently, only oral selexipag (OS) and oral treprostinil (OT) have this mechanism of action and are available in the United States (US). A recent database analysis has shown significantly lower hospitalization risk for patients treated with OS versus OT. Nevertheless, differences in hospitalization and treatment costs among PAH patients taking oral prostacyclin pathway agents (PPAs) in the US healthcare system remain unclear. This study aims to estimate the difference in costs for patients who achieve a stable maintenance dose from a US payer perspective.

MATERIALS AND METHODS

We developed a cost calculator including direct medical costs from the US third-party payer perspective to estimate PAH-related hospitalizations and costs associated with oral PPA use over 2 years, in a hypothetical US payer plan with 1 million members. The treatment-eligible population was estimated from real-world epidemiological data. Treatment-specific hospitalizations were estimated from a study using the Optum Clinformatics administrative claims database. Influence of each model parameter was tested in one-way sensitivity analyses (OWSA), while scenario analysis tested the impact of key assumptions.

RESULTS

For 78 PAH patients included in the model, the base case scenario estimated total costs of $46,736,768 with 98 PAH-related admissions for OS, and total costs of $60,113,620 and 161 PAH-related admissions over 2 years for OT. Using OS was associated with 22.3% cost reduction and 39.1% hospitalizations averted; the number of patients needed treated with selexipag to avoid one hospital admission was 1.23. OWSA indicated medication cost was the most sensitive parameter, followed by population parameters.

LIMITATIONS AND CONCLUSIONS

OS use over 2 years would result in lower total, drug, and hospitalization-related costs compared with OT, thus providing financial savings for payers.

Time to diagnosis of pulmonary hypertension and diagnostic burden: A retrospective analysis of nationwide US healthcare data

The main aim of this analysis was to investigate time from symptom onset (chronic unexplained dyspnoea [CUD]) to diagnosis of Group 1 pulmonary hypertension (PH)-pulmonary arterial hypertension (PAH)-and to characterize healthcare resource utilization leading up to diagnosis using a nationwide US claims and an electronic health record (EHR) database from Optum©. Eligible patients were ≥18 years old at first CUD diagnosis (index event) and had a PAH diagnosis on or after index date. Based on administrative codes, PAH was defined as right heart catheterization (RHC), ≥ 2 PAH diagnoses (1 within a year of RHC), and ≥1 post-RHC prescription for PAH treatment. All values are median (1st quartile-3rd quartile) unless otherwise stated. Of 854,722 patients with CUD in the claims database, 582 (0.1%) had PAH. Time from CUD to PAH diagnosis was 2.26 (0.73-4.22) years. PAH patients experienced 3 (2-4) transthoracic echocardiograms (TTEs), 6 (3-12) specialist visits, and 2 (1-4) hospitalizations during the diagnostic interval. Almost one-third of patients (29%) waited 10 months or more to have a TTE. Findings from the EHR database were broadly similar. Resource utilization during the diagnostic interval was also analyzed in an overall PH cohort: findings were generally similar to the PAH cohort (2 [1-3] TTEs, 4 [2-9] specialist visits and 2 [1-4] hospitalizations). These data indicate a delay in the diagnostic pathway for PAH, and illustrate the burden associated with PAH diagnosis.

The direct and indirect health care costs associated with pulmonary arterial hypertension among commercially insured patients in the United States

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare, progressive, and fatal disease associated with considerable overall clinical and economic burden. Although the direct health care costs of PAH have been well described, there are few data regarding indirect costs and productivity loss associated with PAH. Patient data were assessed until the earliest of death, end of full-time employment, end of continuous enrollment, or end of study period. OBJECTIVES: To update data on the direct burden and address the knowledge gap regarding the indirect burden associated with PAH. METHODS: This is a retrospective case-control study with prevalent and incident patients with PAH aged 18-64 years identified from the MarketScan Commercial and Health and Productivity management datasets during the identification period (January 1, 2016, to November 30, 2018). Patients were required to have continuous enrollment for 12 months or longer from the baseline period and 1 month or longer from the follow-up (post-index) period. Among patients with PAH (cases), the first observed PAH diagnosis claim date during the identification period was the index date. Patients without PAH (controls) were selected and assigned a random index date during the same period. Controls were matched 1:1 by age, sex, and region to prevalent and incident PAH cases. Per patient per month (PPPM), all-cause health care resource utilization, costs, and short-term disability (STD) were examined for cases and controls during the follow-up period. Multivariable analysis was performed using the generalized linear model to determine the adjusted direct and indirect health care utilization and costs. RESULTS: A total of 1,293 prevalent and 455 incident patients with PAH were identified. During the follow-up period, prevalent patients with PAH had significantly higher total mean all-cause health care costs ($9,915 vs $359, P < 0.0001) and inpatient length of stay (0.63 vs 0.02 days, P < 0.0001) PPPM as compared with controls. Prevalent patients with PAH had significantly longer STD (6.0 vs 1.5 days, P < 0.0001) and higher STD-related costs ($1,226 vs $277, P < 0.0001) PPPM as compared with controls. Incident patients with PAH had significantly higher total mean all-cause health care costs ($9,353 vs $336, P < 0.0001) and inpatient length of stay (0.92 vs 0.01 days, P < 0.0001) PPPM as compared with controls. Incident patients with PAH also had longer STD (8.1 vs 1.5 days, P < 0.0001) and higher STD-related costs ($1,706 vs $263, P < 0.0001), as compared with controls. CONCLUSIONS: This study showed that incident and prevalent patients with PAH had significantly higher direct and indirect health care resource utilization and costs as well as productivity loss compared with patients without PAH. DISCLOSURES: Ms Ogbomo and Mr Mallampati were paid employees of STATinMED Research at the time of study completion; STATinMED Research is a paid consultant to Janssen Scientific Affairs, LLC. Drs Tsang and Panjabi are employees of Janssen Scientific Affairs LLC, a subsidiary of Johnson and Johnson, the study sponsor.

JAGGED-NOTCH3 signaling in vascular remodeling in pulmonary arterial hypertension

Within the pulmonary arterial tree, the NOTCH3 pathway is crucial in controlling vascular smooth muscle cell proliferation and maintaining smooth muscle cells in an undifferentiated state. Pulmonary arterial hypertension (PAH) is a fatal disease without cure, characterized by elevated pulmonary vascular resistance due to vascular smooth muscle cell proliferation in precapillary arteries, perivascular inflammation, and asymmetric neointimal hyperplasia. Here, we show that human PAH is characterized by overexpression of the NOTCH ligand JAGGED-1 (JAG-1) in small pulmonary artery smooth muscle cells and that JAG-1 selectively controls NOTCH3 signaling and cellular proliferation in an autocrine fashion. In contrast, the NOTCH ligand DELTA-LIKE 4 is minimally expressed in small pulmonary artery smooth muscle cells from individuals with PAH, inhibits NOTCH3 cleavage and signaling, and retards vascular smooth muscle cell proliferation. A new monoclonal antibody for the treatment of PAH, which blocks JAG-1 cis- and trans-induced cleavage of the NOTCH3 receptor in the pulmonary vasculature, was developed. Inhibition of JAG-1-induced NOTCH3 signaling in the lung reverses clinical and pathologic pulmonary hypertension in two rodent models of disease, without toxic side effects associated with nonspecific NOTCH inhibitors. Our data suggest opposing roles of NOTCH ligands in the pulmonary vasculature in pulmonary hypertension. We propose that selectively targeting JAG-1 activation of NOTCH3 may be an effective, safe strategy to treat PAH.

Mechanisms of pulmonary vascular dysfunction in pulmonary hypertension and implications for novel therapies

Pulmonary hypertension (PH) is a serious disease characterized by various degrees of pulmonary vasoconstriction and progressive fibroproliferative remodeling and inflammation of the pulmonary arterioles that lead to increased pulmonary vascular resistance, right ventricular hypertrophy, and failure. Pulmonary vascular tone is regulated by a balance between vasoconstrictor and vasodilator mediators, and a shift in this balance to vasoconstriction is an important component of PH pathology, Therefore, the mainstay of current pharmacological therapies centers on pulmonary vasodilation methodologies that either enhance vasodilator mechanisms such as the NO-cGMP and prostacyclin-cAMP pathways and/or inhibit vasoconstrictor mechanisms such as the endothelin-1, cytosolic Ca2+, and Rho-kinase pathways. However, in addition to the increased vascular tone, many patients have a "fixed" component in their disease that involves altered biology of various cells in the pulmonary vascular wall, excessive pulmonary artery remodeling, and perivascular fibrosis and inflammation. Pulmonary arterial smooth muscle cell (PASMC) phenotypic switch from a contractile to a synthetic and proliferative phenotype is an important factor in pulmonary artery remodeling. Although current vasodilator therapies also have some antiproliferative effects on PASMCs, they are not universally successful in halting PH progression and increasing survival. Mild acidification and other novel approaches that aim to reverse the resident pulmonary vascular pathology and structural remodeling and restore a contractile PASMC phenotype could ameliorate vascular remodeling and enhance the responsiveness of PH to vasodilator therapies.

Prevalence, incidence, and survival of pulmonary arterial hypertension: A systematic review for the global burden of disease 2020 study

Pulmonary arterial hypertension (PAH) is characterized by increased resistance in the pulmonary arterioles as a result of remodeled blood vessels. We sought all available epidemiologic data on population‐based prevalence, incidence, and 1‐year survival of PAH as part of the Global Burden of Disease Study. We performed a systematic review searching Global Index Medicus (GIM) for keywords related to PAH between 1980 and 2021 and identified population‐representative sources of prevalence, incidence, and mortality for clinically diagnosed PAH. Of 6772 articles identified we found 65 with population‐level data: 17 for prevalence, 17 for incidence, and 58 reporting case fatality. Reported prevalence ranged from 0.37 cases/100,000 persons in a referral center of French children to 15 cases/100,000 persons in an Australian study. Reported incidence ranged from 0.008 cases/100,000 person‐years in Finland, to 1.4 cases/100,000 person‐years in a retrospective chart review at a clinic in Utah, United States. Reported 1‐year survival ranged from 67% to 99%. All studies with sex‐specific estimates of prevalence or incidence reported higher levels in females than males. Studies varied in their size, study design, diagnostic criteria, and sampling procedures. Reported PAH prevalence, incidence, and mortality varied by location and study. Prevalence ranged from 0.4 to 1.4 per 100,000 persons. Harmonization of methods for PAH registries would improve efforts at disease surveillance. Results of this search contribute to ongoing efforts to quantify the global burden of PAH.

Epigenetic Mechanisms as Emerging Therapeutic Targets and Microfluidic Chips Application in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease that progress over time and is defined as an increase in pulmonary arterial pressure and pulmonary vascular resistance that frequently leads to right-ventricular (RV) failure and death. Epigenetic modifications comprising DNA methylation, histone remodeling, and noncoding RNAs (ncRNAs) have been established to govern chromatin structure and transcriptional responses in various cell types during disease development. However, dysregulation of these epigenetic mechanisms has not yet been explored in detail in the pathology of pulmonary arterial hypertension and its progression with vascular remodeling and right-heart failure (RHF). Targeting epigenetic regulators including histone methylation, acetylation, or miRNAs offers many possible candidates for drug discovery and will no doubt be a tempting area to explore for PAH therapies. This review focuses on studies in epigenetic mechanisms including the writers, the readers, and the erasers of epigenetic marks and targeting epigenetic regulators or modifiers for treatment of PAH and its complications described as RHF. Data analyses from experimental cell models and animal induced PAH models have demonstrated that significant changes in the expression levels of multiple epigenetics modifiers such as HDMs, HDACs, sirtuins (Sirt1 and Sirt3), and BRD4 correlate strongly with proliferation, apoptosis, inflammation, and fibrosis linked to the pathological vascular remodeling during PAH development. The reversible characteristics of protein methylation and acetylation can be applied for exploring small-molecule modulators such as valproic acid (HDAC inhibitor) or resveratrol (Sirt1 activator) in different preclinical models for treatment of diseases including PAH and RHF. This review also presents to the readers the application of microfluidic devices to study sex differences in PAH pathophysiology, as well as for epigenetic analysis.

Development and validation of a claims-based model to identify patients at risk of chronic thromboembolic pulmonary hypertension following acute pulmonary embolism

OBJECTIVE

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease that often follows pulmonary embolism (PE). Screening for CTEPH is challenging, often delaying diagnosis and worsening prognosis. Predictive risk models for CTEPH could help identify at-risk patients, but existing models require multiple clinical inputs. We developed and validated a predictive risk model for CTEPH using health insurance claims that can be used by payers/quality-of-care organizations to screen patients post-PE.

METHODS

Adult patients newly diagnosed with acute PE (index date) were identified from the Optum De-identified Clinformatics Extended DataMart (January 2007-March 2018; development set) and IBM MarketScan (January 2008-June 2019; validation set) databases. Predictors were identified 12 months before or on the index PE. Risk of "likely CTEPH" was assessed post-PE based on CTEPH-related diagnoses and procedures since the CTEPH diagnosis code (ICD-10-CM: I27.24) was not available until 1 October 2017. Stepwise variable selection was used to build the model using the development set; model validation was subsequently conducted using the validation set.

RESULTS

The development set included 93,428 patients, of whom 11,878 (12.7%) developed likely CTEPH. Older age (odds ratios [OR] = 1.16-1.49), female (OR = 1.09), unprovoked PE (i.e. without thrombotic factors; OR = 1.14), hypertension (OR = 1.07), osteoarthritis (OR = 1.08), diabetes (OR = 1.07), chronic obstructive pulmonary disease (OR = 1.11), obesity (OR = 1.21) were associated with higher odds of likely CTEPH, and oral anticoagulants with lower odds (OR= 0.50, all p < .01). C-statistic was 0.77 in the development and validation sets.

CONCLUSION

A claims-based risk model reliably predicted the risk of CTEPH post-PE and could be used to identify high-risk patients who may benefit from focused monitoring.

Interventional and pharmacological management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by obstruction of the pulmonary vasculature, leading to increased pulmonary vascular resistance and ultimately right ventricular failure, the leading cause of death in non-operated patients. This article reviews the current management of CTEPH. The standard of care in CTEPH is pulmonary endarterectomy (PEA). However, up to 40% of patients with CTEPH are ineligible for PEA, and up to 51% develop persistent/recurrent PH after PEA. Riociguat is currently the only medical therapy licensed for treatment of inoperable or persistent/recurrent CTEPH after PEA based on the results of the Phase III CHEST-1 study. Studies of balloon pulmonary angioplasty (BPA) have shown benefits in patients with inoperable or persistent/recurrent CTEPH after PEA; however, data are lacking from large, prospective, controlled studies. Studies of macitentan in patients with inoperable CTEPH and treprostinil in patients with inoperable or persistent/recurrent CTEPH showed positive results. Combination therapy is under evaluation in CTEPH, and long-term data are not available. In the future, CTEPH may be managed by PEA, medical therapy or BPA - alone or in combination, according to individual patient needs. Patients should be referred to experienced centers capable of assessing and delivering all options.

Epidemiology of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: identification of the most accurate estimates from a systematic literature review

This systematic review of literature and online reports critically appraised incidence and prevalence estimates of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension to identify the most accurate estimates. Medline® and Embase® databases were searched for articles published between 1 January 2003 and 31 August 2020. Studies were grouped according to whether they were registries (population-based estimates), clinical databases (hospital-based estimates) or claims/administrative databases. Registries were classified into systematic and non-systematic registries, according to whether every national centre participated. Of 7309 publications identified, 5414 were screened after removal of duplicates and 33 were included. Inclusion was based on study type, availability of a clear numerator (diagnosed population) and a population- or hospital-based denominator, or all primary data required to calculate estimates. Only the most recent publication from a database was included. Most studies were based on European data and very few included children. In adults, the range of estimates per million was approximately 20-fold for pulmonary arterial hypertension incidence (1.5-32) and prevalence (12.4-268) and of similar magnitude for chronic thromboembolic pulmonary hypertension incidence (0.9-39) and prevalence (14.5-144). Recent (≤5 years) national systematic registry data from centralised healthcare systems provided the following ranges in adult estimates per million: approximately 5.8 for pulmonary arterial hypertension incidence, 47.6-54.7 for pulmonary arterial hypertension prevalence, 3.1-6.0 for chronic thromboembolic pulmonary hypertension incidence and 25.8-38.4 for chronic thromboembolic pulmonary hypertension prevalence. These estimates were considered the most reliable and consistent for the scientific community to plan for resource allocation and improve detection rates.

Evaluation of code-based algorithms to identify pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension patients in large administrative databases

Large administrative healthcare (including insurance claims) databases are used for various retrospective real-world evidence studies. However, in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, identifying patients retrospectively based on administrative codes remains challenging, as it relies on code combinations (algorithms) and the accuracy for patient identification of most of them is unknown. This study aimed to assess the performance of various algorithms in correctly identifying patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension in administrative databases. A systematic literature review was performed to find publications detailing code-based algorithms used to identify pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension patients. PheValuator, a diagnostic predictive modelling tool, was applied to three US claims databases, yielding models that estimated the probability of a patient having the disease. These models were used to evaluate the performance characteristics of selected pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension algorithms. With increasing algorithm complexity, average positive predictive value increased (pulmonary arterial hypertension: 13.4–66.0%; chronic thromboembolic pulmonary hypertension: 10.3–75.1%) and average sensitivity decreased (pulmonary arterial hypertension: 61.5–2.7%; chronic thromboembolic pulmonary hypertension: 20.7–0.2%). Specificities and negative predictive values were high (≥97.5%) for all algorithms. Several of the algorithms performed well overall when considering all of these four performance parameters, and all algorithms performed with similar accuracy across the three claims databases studied, even though most were designed for patient identification in a specific database. Therefore, it is the objective of a study that will determine which algorithm may be most suitable; one- or two-component algorithms are most inclusive and three- or four-component algorithms identify most precise pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension populations, respectively.

Beyond the genome: challenges and potential for epigenetics-driven therapeutic approaches in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease of the cardiopulmonary system caused by the narrowing of the pulmonary arteries, leading to increased vascular resistance and pressure. This leads to right ventricle remodeling, dysfunction, and eventually, death. While conventional therapies have largely focused on targeting vasodilation, other pathological features of PAH including aberrant inflammation, mitochondrial dynamics, cell proliferation, and migration have not been well explored. Thus, despite some recent improvements in PAH treatment, the life expectancy and quality of life for patients with PAH remains poor. Showing many similarities to cancers, PAH is characterized by increased pulmonary arterial smooth muscle cell proliferation, decreased apoptotic signaling pathways, and changes in metabolism. The recent successes of therapies targeting epigenetic modifiers for the treatment of cancer has prompted epigenetic research in PAH, revealing many new potential therapeutic targets. In this minireview we discuss the emergence of epigenetic dysregulation in PAH and highlight epigenetic-targeting compounds that may be effective for the treatment of PAH.

Identifying Patients with Pulmonary Arterial Hypertension Using Administrative Claims Algorithms

Retrospective administrative claims database studies provide real-world evidence about treatment patterns, healthcare resource use, and costs for patients and are increasingly used to inform policy-making, drug formulary, and regulatory decisions. However, there is no standard methodology to identify patients with pulmonary arterial hypertension (PAH) from administrative claims data. Given the number of approved drugs now available for patients with PAH, the cost of PAH treatments, and the significant healthcare resource use associated with the care of patients with PAH, there is a considerable need to develop an evidence-based and systematic approach to accurately identify these patients in claims databases. A panel of pulmonary hypertension clinical experts and researchers experienced in retrospective claims database studies convened to review relevant literature and recommend best practices for developing algorithms to identify patients with PAH in administrative claims databases specific to a particular research hypothesis.

Psychosocial and Financial Burden of Therapy in USA Patients with Pulmonary Arterial Hypertension

Abstract: Pulmonary arterial hypertension (PAH) is a devastating disease with significant morbidity and mortality. There are many psychosocial and financial implications of this disease; however, little is known how this affects the treatment of PAH patients. A questionnaire-based prospective cohort study was performed on 106 PAH patients from a Pulmonary Hypertension Center and the Pulmonary Hypertension Association national conference in 2018. The demographic, treatment, psychosocial, employment, financial impact on treatment data was obtained. The majority of patients had cardiopulmonary symptoms despite treatment. The symptoms affected their social and work lives, with about one in three applying for disability because of their PAH. The majority of PAH patients had insurance coverage, but still noted a significant financial burden of the disease, with nearly a half who needed financial assistance to pay for their PAH medications. Thirty (28.3%; 95% CI, 20.6-37.5%) patients mentioned they changed their medication regimen, with some skipping doses outright (28 [26.4%; 95% CI, 19-35.6%]) in order to save money. PAH continues to cause significant psychosocial and financial burden on patients despite advances in medications. This impact ranged from dissatisfaction with quality of life, to unemployment, to altering their medication regimen to save money.

The Public Health Burden of Cardiomyopathies: Insights from a Nationwide Inpatient Study

Cardiomyopathies are responsible for heart failure and sudden cardiac death, but epidemiological data are scarce and the public health burden may be underestimated. We studied aggregating data from all public or private hospitals in France. Patients were categorized from relevant ICD-10 codes into dilated, hypertrophic, restrictive, or other cardiomyopathies (DCM, HCM, RCM, or OCM, respectively). Between 2008 and 2015, a total of 326,461 distinct patients had cardiomyopathy-related hospitalizations. The hospital-based prevalence of cardiomyopathy was 809 per million inhabitants (PMI) per year, including 428 PMI for DCM, 101 PMI for HCM, 26 PMI for RCM, and 253 PMI for OCM. Patients with cardiomyopathies accounted for 51% of all heart transplants, 33% of defibrillator implantations, 38% of mechanical circulatory supports, and 11.3% of hospitalizations for heart failure. In patients less than 40 years of age, these figures were 71%, 51%, 63%, and 23%, respectively. Over 2008–2015 and considering all cardiomyopathies, there was a significant increase for heart transplant (average annual percentage change, AAPC: +3.86%, p = 0.0015) and for defibrillator implantation (AAPC: +6.98%, p < 0.0001), and a significant decrease of in-hospital mortality (AAPC: −4.7%, p = 0.0002). This nationwide study shows that cardiomyopathies constitute an important cause of hospitalization, with increasing invasive therapeutic procedures and decreasing mortality.

Characterizing Health Outcomes in Idiopathic Pulmonary Fibrosis using US Health Claims Data

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a life-threatening interstitial lung disease (ILD). Characterizing health outcomes of IPF patients is challenging due to disease rarity.

OBJECTIVE

This study aimed to identify the burden of disease in patients newly diagnosed with IPF.

METHODS

Patients with ≥1 claim with an IPF diagnosis were identified from a United States healthcare insurer's database (2000-2013). Patients with other known causes of ILD or aged <40 years were excluded. Subgroups were compared based on the 2011 change in International Classification of Diseases, 9th Revision (ICD-9) definition of IPF and occurrence of IPF testing. The prevalence and incidence of preselected health conditions of clinical interest were estimated.

RESULTS

Median age of newly diagnosed patients (n = 7,298) was 62 years (54.0% male). Restricting to patients with IPF diagnostic testing did not substantially affect cohort characteristics, nor did ICD-9 IPF coding change. Mean follow-up was 1.7 years; 16.8% of patients died; and a substantial proportion of patients were censored due to end of health plan enrollment (50.7%) and other causes of ILD (19.6%). The incidence of pulmonary hypertension, lung cancer, and claims-based algorithm proxy for acute respiratory worsening of unknown cause was 22.5, 17.6, and 12.6 per 1,000 person-years, respectively.

CONCLUSIONS

Patients with IPF had a high disease burden with a variety of health outcomes observed, including a high rate of mortality. Database censoring due to changes in enrollment or other ILD diagnoses limited follow-up. Altering cohort entry definitions, including IPF testing or ICD-9 IPF coding change, had little impact on cohort baseline characteristics.

The SGLT2 inhibitor empagliflozin reduces mortality and prevents progression in experimental pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a rare, but progressive and devastating vascular disease with few treatment options to prevent the advancement to right ventricular dysfunction hypertrophy and failure. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, enhances urinary glucose excretion as well as reduces cardiovascular events and mortality in individuals with type 2 diabetes. While empagliflozin has been reported to lower systemic hypertension due to increased diuresis, the effect of empagliflozin on PAH is unknown. We used monocrotaline (MCT)-treated Sprague-Dawley rats to determine if empagliflozin alters PAH-associated outcomes. Compared to vehicle control, daily empagliflozin administration significantly improved survival in rats with severe MCT-induced PAH. Hemodynamic assessments showed that empagliflozin treatment significantly reduced mean pulmonary artery pressure, right ventricular systolic pressure, and increased pulmonary acceleration time. Empagliflozin treatment resulted in reduced right ventricular hypertrophy and fibrosis. Histological and molecular assessments of lung vasculature revealed significantly reduced medial wall thickening and decreased muscularization of pulmonary arterioles after empagliflozin treatment compared to vehicle-treated rats. In summary, SGLT2 inhibition with empagliflozin lowered mortality, reduced right ventricle systolic pressure, and attenuated maladaptive pulmonary remodeling in MCT-induced PAH. Clinical studies evaluating the efficacy of SGLT-2 inhibition should be considered for patients with PAH.

Therapeutic Challenges And Advances In The Management Of Systemic Sclerosis-Related Pulmonary Arterial Hypertension (SSc-PAH)

Systemic sclerosis (SSc) is a rare autoimmune disorder with multi-organ involvement. SSc-associated pulmonary arterial hypertension (SSc-PAH) is one of the leading causes of morbidity and mortality in the SSc population. With advances in our understanding of pulmonary arterial hypertension (PAH) diagnosis and treatment, outcomes for all PAH patients have significantly improved. While SSc-PAH patients have also benefited from these advances, significant challenges remain. Diagnosis of PAH is a challenging endeavor in SSc patients who often have many co-existing pulmonary and cardiac comorbidities. Given the significantly elevated prevalence and lifetime risk of PAH in the SSc population, screening for SSc-PAH is a critically useful strategy. Treatment with pulmonary arterial (PA) vasodilators has resulted in a dramatic improvement in the survival and quality of life of PAH patients. While therapy with PA vasodilators is beneficial in SSc-PAH patients, therapy effects appear to be attenuated when compared to responses in patients with idiopathic PAH (IPAH). This review attempts to chronicle and summarize the advances in our understanding of the optimal screening strategies to identify PAH in patients with SSc. The article also reviews the advances in the therapeutic and risk stratification strategies for SSc-PAH patients.

Cardiac remodelling in a swine model of chronic thromboembolic pulmonary hypertension: comparison of right vs. left ventricle

KEY POINTS

Right ventricle (RV) function is the most important determinant of survival and quality of life in patients with chronic thromboembolic pulmonary hypertension (CTEPH). The changes in right and left ventricle gene expression that contribute to ventricular remodelling are incompletely investigated. RV remodelling in our CTEPH swine model is associated with increased expression of the genes involved in inflammation (TGFβ), oxidative stress (ROCK2, NOX1 and NOX4), and apoptosis (BCL2 and caspase-3). Alterations in ROCK2 expression correlated inversely with RV contractile reserve during exercise. Since ROCK2 has been shown to be involved in hypertrophy, oxidative stress, fibrosis and endothelial dysfunction, ROCK2 inhibition may present a viable therapeutic target in CTEPH.

ABSTRACT

Right ventricle (RV) function is the most important determinant of survival and quality of life in patients with chronic thromboembolic pulmonary hypertension (CTEPH). The present study investigated whether the increased cardiac afterload is associated with (i) cardiac remodelling and hypertrophic signalling; (ii) changes in angiogenic factors and capillary density; and (iii) inflammatory changes associated with oxidative stress and interstitial fibrosis. CTEPH was induced in eight chronically instrumented swine by chronic nitric oxide synthase inhibition and up to five weekly pulmonary embolizations. Nine healthy swine served as a control. After 9 weeks, RV function was assessed by single beat analysis of RV-pulmonary artery (PA) coupling at rest and during exercise, as well as by cardiac magnetic resonance imaging. Subsequently, the heart was excised and RV and left ventricle (LV) tissues were processed for molecular and histological analyses. Swine with CTEPH exhibited significant RV hypertrophy in response to the elevated PA pressure. RV-PA coupling was significantly reduced, correlated inversely with pulmonary vascular resistance and did not increase during exercise in CTEPH swine. Expression of genes associated with hypertrophy (BNP), inflammation (TGFβ), oxidative stress (ROCK2, NOX1 and NOX4), apoptosis (BCL2 and caspase-3) and angiogenesis (VEGFA) were increased in the RV of CTEPH swine and correlated inversely with RV-PA coupling during exercise. In the LV, only significant changes in ROCK2 gene-expression occurred. In conclusion, RV remodelling in our CTEPH swine model is associated with increased expression of genes involved in inflammation and oxidative stress, suggesting that these processes contribute to RV remodelling and dysfunction in CTEPH and hence represent potential therapeutic targets.

Identifying chronic thromboembolic pulmonary hypertension through the French national hospital discharge database

Chronic thromboembolic pulmonary hypertension (CTEPH), a rare pulmonary vascular disease, is often misdiagnosed due to nonspecific symptoms. The objective of the study was to develop, refine and validate a case ascertainment algorithm to identify CTEPH patients within the French exhaustive hospital discharge database (PMSI), and to use it to estimate the annual number of hospitalized patients with CTEPH in France in 2015, as a proxy for disease prevalence. As ICD-10 coding specifically for CTEPH was not available at the time of the study, a case ascertainment algorithm was developed in close collaboration with an expert committee, using a two-step process (refinement and validation), based on matched data from PMSI and hospital medical records from 2 centres. The best-performing algorithm (specificity 95%, sensitivity 70%) consisted of ≥1 pulmonary hypertension (PH) diagnosis during 2015 and any of the following criteria over 2009-2015: (i) CTEPH interventional procedure, (ii) admission for PH and pulmonary embolism (PE), (iii) PE followed by hospitalization in competence centre then in reference centre, (iv) history of PE and right heart catheterization. Patients with conditions suggestive of pulmonary arterial hypertension were excluded. A total of 3,138 patients hospitalized for CTEPH was estimated for 2015 (47 cases/million, range 43 to 50 cases/million). Assuming that patients are hospitalized at least once a year, the present study provides an estimate of the minimal prevalence of CTEPH and confirms the heavy burden of this disease.

Characterizing idiopathic pulmonary fibrosis patients using US Medicare-advantage health plan claims data

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a rare life-threating interstitial lung disease (ILD). This study characterizes demographics, health care utilization, and comorbidities among elderly IPF patients and estimates prevalence and incidence rates for selected outcomes.

METHODS

Cohort study using a large US health insurance database (Optum's Medicare Advantage plan).

INCLUSION CRITERIA

≥ 1 diagnosis code for IPF (2008 - 2014), age ≥65 years, no diagnosis of IPF or other ILD in prior 12 months. Demographics, health care utilization, comorbidities and incidence rates for various outcomes were estimated. Follow-up continued until the earliest of: health plan disenrollment, death, a claim for another known cause of ILD, or end of the study period.

RESULTS

4,716 patients were eligible; 53.4% had IPF diagnostic testing. Median age was 77.5 years, 50.3% were male, median follow-up time was 0.8 years. Incidence rates ranged from 1.0/1,000 person-years (lung transplantation) to 374.3/1,000 person-years (arterial hypertension). Baseline characteristics and incidence rates were similar for cohorts of patients with and without IPF diagnostic testing.

CONCLUSIONS

Elderly IPF patients experience a variety of comorbidities before and after IPF diagnosis. Therapies for IPF and for the associated comorbidities may reduce morbidity and associated health care utilization of these patients.

Accuracy of Algorithms to Identify Pulmonary Arterial Hypertension in Administrative Data: A Systematic Review

BACKGROUND

The diagnosis of pulmonary arterial hypertension (PAH) is challenging, and there is significant overlap with the more heterogenous diagnosis of pulmonary hypertension (PH). Clinical and research efforts that rely on administrative data are limited by current coding systems that do not adequately reflect the clinical classification scheme. The aim of this systematic review is to investigate current algorithms to detect PAH using administrative data and to appraise the diagnostic accuracy of these algorithms against a reference standard.

METHODS

We conducted comprehensive searches of Medline, Embase, and Web of Science from their inception. We included English-language articles that applied an algorithm to an administrative or electronic health record database to identify PAH in adults.

RESULTS

Of 2,669 unique citations identified, 32 studies met all inclusion criteria. Only four of these studies validated their algorithm against a reference standard. Algorithms varied widely, ranging from single International Classification of Diseases (ICD) codes to combinations of visit, procedure, and pharmacy codes. ICD codes alone performed poorly, with positive predictive values ranging from 3.3% to 66.7%. The addition of PAH-specific therapy and diagnostic procedures to the algorithm improved the diagnostic accuracy.

CONCLUSIONS

Algorithms to identify PAH in administrative databases vary widely, and few are validated. The sole use of ICD codes performs poorly, potentially leading to biased results. ICD codes should be revised to better discriminate between PH groups, and universally accepted algorithms need to be developed and validated to capture PAH in administrative data, better informing research and clinical efforts.

Breathing (and Coding?) a Bit Easier: Changes to International Classification of Disease Coding for Pulmonary Hypertension

The International Classification of Disease (ICD) coding system is broadly used by health-care providers, hospitals, health-care payers, and governments to track health trends and statistics at the global, national, and local levels and to provide a reimbursement framework for medical care based on diagnosis and severity of illness. The current iteration of the ICD system, the ICD, Tenth Revision (ICD-10), was implemented in 2015. Although many changes to the prior ICD, Ninth Revision system were included in the ICD-10 system, the newer revision failed to adequately reflect advances in the clinical classification of certain diseases such as pulmonary hypertension (PH). Recently, a proposal to modify the ICD-10 codes for PH was considered and ultimately adopted for inclusion as an update to the ICD-10 coding system. Although these revisions better reflect the current clinical classification of PH, in the future, further changes should be considered to improve the accuracy and ease of coding for all forms of PH.

Validation of claims-based algorithms for pulmonary arterial hypertension

Administrative claims studies do not adequately distinguish pulmonary arterial hypertension (PAH) from other forms of pulmonary hypertension (PH). Our aim is to develop and validate a set of algorithms using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and electronic medical records (EMR), to identify patients with PAH. From January 2012 to August 2015, the EMRs of patients with ICD-9-CM codes for PH with an outpatient visit at the University of Texas Medical Branch were reviewed. Patients were divided into PAH or non-PAH groups according to EMR encounter diagnosis. Patient demographics, echocardiography, right heart catheterization (RHC) results, and PAH-specific therapies were assessed. RHC measurements were reviewed to categorize cases as hemodynamically determined PAH or not PAH. Weighted sensitivity, specificity, and positive and negative predictive values were calculated for the developed algorithms. A logistic regression analysis was conducted to determine how well the algorithms performed. External validation was performed at the University of Virginia Health System. The cohort for the development algorithms consisted of 683 patients with PH, PAH group (n = 191) and non-PAH group (n = 492). A hemodynamic diagnosis of PAH determined by RHC was recorded in the PAH (26%) and non-PAH (3%) groups. The positive predictive value for the algorithm that included ICD-9-CM and PAH-specific medications was 66.9% and sensitivity was 28.2% with a c-statistic of 0.66. The positive predictive value for the EMR-based algorithm that included ICD-9-CM, EMR encounter diagnosis, echocardiography, RHC, and PAH-specific medication was 69.4% and a c-statistic of 0.87. A validation cohort of 177 patients with PH examined from August 2015 to August 2016 using EMR-based algorithms yielded a similar positive predictive value of 62.5%. In conclusion, claims-based algorithms that included ICD-9-CM codes, EMR encounter diagnosis, echocardiography, RHC, and PAH-specific medications better-identified patients with PAH than ICD-9-CM codes alone.

Anxiety, Depression, and Health-Related QOL in Patients Diagnosed with PAH or CTEPH

BACKGROUND

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are life-threatening diseases with a high burden of symptoms. Although depression, anxiety, and reduced health related quality of life (HRQOL) have also been reported, a comparative analysis which explores these traits and their underlying factors was lacking.

METHODS

A retrospective analysis of depression, anxiety, and health related QOL was conducted using a Hospital anxiety and depression scale (HADS) as well as the SF-36 HRQOL questionnaire. Results from these tools were compared with haemodynamic and functional parameters in 70 PAH and 23 CTEPH outpatients from a German tertiary care center specializing in pulmonary hypertension.

RESULTS

Although HRQOL was reduced in both cohorts of patients, individuals diagnosed with CTEPH scored lower in nearly all SF-36 parameters. Significance was noted in both "mental health" (p = 0.01) and "mental component summary score" (MCS) (p = 0.02). Depression was also more frequent in patients with CTEPH (56%) than in patients with PAH (30%), (p = 0.03). Overall, depression and anxiety correlated with most SF-36 scales in both PAH and CTEPH. In CTEPH, depression also correlated with the Borg Dyspnea Scale (r = 0.44, p = 0.01). These patients also had significantly lower pCO₂ levels than the PAH cohort reflecting more severe ventilation/perfusion mismatch. All other haemodynamic and functional parameters did not differ across the groups.

CONCLUSION

While both cohorts of patients suffer from a reduced HRQOL as well as depression and anxiety, decreases in mental health parameters are more pronounced in the CTEPH cohort. This suggests a strong effort to improve early detection, especially in dyspneic patients with classical risk factors for CTEPH and PAH and argues for mental illness interventions alongside routine clinical care provided to patients diagnosed with PAH or CTEPH.

Modern diagnosis of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) should be suspected in patients presenting persistent dyspnea three months after a pulmonary embolism or in patients presenting with acute pulmonary embolism and suggestive images on the CT-scan. For these patients, a specific diagnostic work-up should be performed. First step consists of the ventilation/perfusion (V/Q) scan which is a good screening test due to its high sensitivity and high negative predictive value. Pulmonary angiography remains the gold standard approach for the confirmation of the diagnosis and pre-surgical evaluation of CTEPH. New emerging technologies such as Dual-Energy Computed Tomography angiography (DECT) and Computed Tomography angiography (CTA) are developing and broadly available. These non invasive methods provide diagnostic information similar to conventional pulmonary angiography and surgical operability information. They are to be considered as an alternative in the diagnostic approach of patients with CTEPH as presented in the ESC/ERS guidelines. Haemodynamic measurement whiles exercising during right heart catheterization may improve diagnostic sensitivity of CTEPH and could therefore be used as a diagnostic test in patient with normal haemodynamic at rest.

A Review of Clinical Trial Endpoints of Patients with Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension and How They Relate to Patient Outcomes in the United States

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are subgroups of pulmonary hypertension and are considered rare diseases. Understanding how endpoints of clinical trials (and patient registry studies) of patients with PAH and CTEPH are associated with patient outcomes is important in order to address the concerns of patients, health care providers, decision makers, and payers. The purpose of this review was to examine how endpoints used in clinical trials and patient registry studies are associated with outcomes of patients with PAH and CTEPH. A PubMed literature search was conducted to retrieve published studies, including randomized phase III clinical trials and observational studies, from years 2000 to May 2015 that evaluated the associations between change in 6-minute walking distance (6MWD), 6MWD thresholds, change in World Health Organization functional class (WHO-FC), and time to clinical worsening with outcomes of patients with PAH and CTEPH. Based on this review of published literature, a reduction in 6MWD as a criterion for PAH worsening, a deterioration in WHO-FC, and delay in the time to clinical worsening are clinically meaningful trial endpoints and are associated with outcomes of patients with PAH and CTEPH. Utilization and standardization of these endpoints will be useful for comparing interventions of clinical trials and therapies. Hospitalizations are frequent among patients with PAH and CTEPH, and total health care costs are high. From a U.S. payer perspective, clinical worsening is an important composite endpoint in that it includes hospitalization, which can be transformed into a preventative cost value associated with efficacious treatment of patients with PAH and CTEPH. In view of the greater number of medications available to treat PAH, the introduction of the first approved therapy to treat CTEPH, and the increasing use of combination pharmacotherapy, reliable prognostic markers of treatment responsiveness are important to help guide appropriate management. As new clinical trials and observational studies are conducted, it will be important to maintain universal endpoints so that health care providers, decision makers, and payers can better understand the value of targeted pharmacotherapies and combination therapies for the treatment of patients with PAH and CTEPH.

DISCLOSURES

Sponsorship for this review and article processing charges were funded by Bayer HealthCare Pharmaceuticals. Divers and Platt are employees of Bayer HealthCare Pharmaceuticals. Wang is an employee of Bayer HealthCare Pharmaceuticals and owns stock in the company. Lin and Lingohr-Smith are employees of Novosys Health, which received research funds from Bayer HealthCare Pharmaceuticals in connection with conducting this review and developing this manuscript. Mathai is a consultant to Bayer HealthCare Pharmaceuticals and also reports consulting fees from Actelion and Gilead. Study concept and design were contributed by Divers, Platt, Lin, and Mathai. Lin and Lingohr-Smith collected the data, and data interpretation was performed by Divers, Platt, Wang, and Matthai. The manuscript was written primarily by Lingohr-Smith, with assistance from the other authors, and revised by Divers, Platt, Wang, and Mathai.

An Update on the Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary artery hypertension that is defined as a mean arterial pulmonary pressure greater than 25mmHg that persists for more than 6 months following anticoagulation therapy in the setting of pulmonary emboli. CTEPH is categorized by the World Health Organization as group IV pulmonary hypertension and is thought to be due to unresolved thromboemboli in the pulmonary artery circulation. Among the 5 classes of pulmonary hypertension, CTEPH is unique in that it is potentially curable with the use of pulmonary thromboendarterectomy surgery. Despite an increasing array of medical and surgical treatment options for patients with CTEPH over the past 2 decades, patients commonly present with advanced disease and carry a poor prognosis, thus, the need for early diagnosis and appropriate referral to an expert center. This review article first highlights the epidemiology, pathophysiology, and clinical presentation of CTEPH. The article then provides diagnostic and therapeutic algorithms for the management of the patient with suspected CTEPH.

Scope of problem of pulmonary arterial hypertension

BACKGROUND

As with many uncommon diseases, data in patients with pulmonary arterial hypertension are sparse in regard to emergency service visits, hospitalizations, and mortality. The purpose of this investigation is to assess the scope of the problem of Group 1 pulmonary arterial hypertension in adults in the US and trends from 2001 to 2007.

METHODS

The Nationwide Emergency Department Sample, 2007-2011, was used to determine the number of emergency department visits, hospitalizations, and all-cause mortality of patients aged ≥18 years with Group 1 pulmonary arterial hypertension. We assessed patients with a discharge code for "primary pulmonary hypertension," and excluded patients with known causes of pulmonary hypertension that are not classified as Group 1.

RESULTS

There were 64,451 emergency department visits and 52,779 hospitalizations for pulmonary arterial hypertension from 2007-2011 in patients aged ≥18 years. The proportion of all emergency department visits that were for pulmonary arterial hypertension decreased from 16.4/100,000 visits in 2007 to 8.9/100,000 visits in 2011 (P < .0001). The proportion of all hospitalizations that were for pulmonary arterial hypertension decreased from 79/100,000 hospitalizations in 2007 to 38/100,000 hospitalizations in 2011 (P < .0001). Population-based death rates in patients with pulmonary arterial hypertension decreased from 4.6/million population in 2007 to 1.7/million population in 2011 (P < .0001).

CONCLUSIONS

Decreasing rates of emergency department visits, hospitalizations, and deaths in patients with Group 1 pulmonary arterial hypertension were shown from 2007-2011. We speculate that this resulted from improved treatment during the period of observation.

Evaluation of WO-2014132220, selective PDGFR inhibitors for the treatment of pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare disease currently treated by a range of vasodilator agents and/or endothelin antagonists. Inhibition of platelet derived growth factor receptor (PDGFR) kinases has been suggested to provide an additional therapeutic modality, and clinical studies with the non-selective PDGFR inhibitor imatinib appear to validate this hypothesis. However, side-effects associated with a lack of selectivity suggest clinical utility requires the identification and development of selective PDGFR inhibitors.

AREAS COVERED

This application claims derivatives and crystalline forms of two previously claimed PDGFR inhibitors and their use for the treatment of PAH. N-(5-(2-(2,2-dimethylpyrrolidin-1-yl)ethylcarbamoyl)-2-methylpyridin-3-yl)-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carboxamide and N-(5-(2-(2,6-cis-dimethylpiperidin-1-yl)ethylcarbamoyl)-2-fluorophenyl)-7-(1-methyl-1H-pyrazol-5-yl)imidazo[1,2-a]pyridine-3-carboxamide have respective IC50 values of 3 and 45 nM in a cellular proliferation assay.

EXPERT OPINION

These two compounds are likely to be selective PDGFR inhibitors. The nature of this filing suggests that Novartis intends to develop at least one of these compounds for the treatment of PAH.

The economic burden of pulmonary arterial hypertension (PAH) in the US on payers and patients

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare condition that can ultimately lead to right heart failure and death. In this study we estimated the health care costs and resource utilization associated with PAH in a large US managed care health plan.

METHODS

Subjects with claims-based evidence of PAH from 1/1/2004 to 6/30/2010 (identification period) were selected. To be included in the final PAH study sample, subjects were required to have ≥2 claims with a primary PH diagnosis; ≥2 claims with a PAH related-diagnosis (connective tissue diseases, congenital heart diseases, portal hypertension); and ≥1 claim with evidence of a PAH-indicated medication. The earliest date of a claim with evidence of PAH-indicated medication during the identification period was set as the index date. Health care costs and resource utilization were compared between an annualized baseline period and a 12 month follow-up period.

RESULTS

504 PAH subjects were selected for the final study cohort. Estimated average total health care costs were approximately 16% lower in the follow-up period compared to the baseline period (follow-up costs = $98,243 [SD = 110,615] vs. baseline costs = $116,681 [SD = 368,094], p < 0.001), but substantively high in each period relative to costs reported for other chronic diseases. Pharmacy costs were significantly higher in the follow-up period vs. the baseline period, ($38,514 [SD = 34,817] vs. $6,440 [SD = 12,186], p < 0.001) but medical costs were significantly lower in the follow-up vs. baseline ($59,729 [SD = 106,683] vs. $110,241 [SD = 368,725], p < 0.001). These costs were mirrored in health-care resource utilization estimates. The average counts of ambulatory visits and inpatient stays were lower in the follow-up vs. the baseline (both p < 0.001). Results varied in exploratory analyses when less restrictive subject identification algorithms were used.

CONCLUSIONS

Subjects with evidence of PAH had substantively high health care costs. Medical costs appeared to decrease following PAH medication use, but with a concomitant increase in pharmacy costs.

Characterizing the financial burden of pulmonary arterial hypertension within an integrated healthcare delivery system

PURPOSE

Financial burden associated with providing healthcare to patients with pulmonary arterial hypertension (PAH) is poorly characterized. This study sought to quantify 3-year healthcare expenditures and determine whether expenditures differed between incident and prevalent PAH cases.

METHODS

This was a retrospective cohort study of Kaiser Permanente Colorado (KPCO) patients with confirmed diagnosis of PAH. Included patients were followed from study entry until 3 years, death, or termination of KPCO membership, whichever came first. All expenditures were reported in 2011 US dollars from the KPCO perspective.

RESULTS

In total, 157 patients were included: 44 (28%) prevalent and 113 (72%) incident cases. Mean age (prevalent vs incident cases) was 61 years vs 67 years and 13.6% vs 27.4% were males. The majority of patients (55%) were classified as WHO Group 1 PAH. Prevalent cases had less follow-up (843 vs 975 days; p = 0.033). Overall, median total per patient per day (PPPD) and 3-year total expenditures were $56 (interquartile range (IQR = $29-$166) and $50,599 (IQR = $25,958-$135,535), respectively. After adjustment for patient characteristics and chronic disease burden, median PPPD ($54 vs $56; p = 0.950) and 3-year ($37,340 vs $55,073; p = 0.111) total expenditures were equivalent between prevalent and incident cases; however, the risk of death during the 3-year follow-up was lower among incident cases (hazard ratio = 0.41, 95% CI = 0.18-0.91). No significant differences were detected in pharmacy, inpatient, medical office, emergency department, or other expenditures. Median PAH specialty medication PPPD expenditures were also equivalent, also ($226 vs $223 among specialty medication users; p = 0.861).

CONCLUSION

Healthcare expenditures related to PAH represent substantial financial burden. Significant differences according to prevalent or incident case status appeared to be driven by median ED and inpatient expenditures; however, PAH specialty medication expenditures represented a substantial cost-driver overall. Future efforts should focus on optimizing care for patients with PAH to avoid unnecessary harm or waste.

Development and validation of the living with pulmonary hypertension questionnaire in pulmonary arterial hypertension patients

BACKGROUND

The Living with Pulmonary Hypertension questionnaire (LPH) was adapted from the Minnesota Living with Heart Failure Questionnaire for use in patients with pulmonary arterial hypertension (PAH). Study objectives were to confirm the face and content validity, to assess the structure and psychometric properties, and provide guidance for the interpretation of the LPH.

METHODS

A qualitative interview study was conducted with PAH patients in the US (n=12), Germany (n=14) and France (n=12) to evaluate the face and content validity of the LPH. Psychometric validation was performed using blinded data from a double blind, Phase III, clinical trial (n=196). Validation analyses were performed on baseline and week 12 (visit 6/last visit) data and included evaluation of: item response distributions, quality of completion, construct validity, reliability, clinical validity and responsiveness. Analyses to provide an estimation of the Minimal Important Difference (MID) for the LPH scores were performed.

RESULTS

Cognitive debriefing interviews with 38 PAH patients indicated that the most commonly reported PAH symptoms and impacts are covered by LPH items. Patients found the LPH questionnaire relevant and comprehensive to their experience. Some suggestions were made to enhance the face validity of the LPH. The content validity of the questionnaire was supported. Results of the psychometric validation analyses (n=190) indicated that the LPH Emotional and Physical scores met the criteria for convergent and discriminant validity; for the total score all but two items met the test for item convergent validity. Internal consistency reliability was demonstrated by Cronbach's alpha values of >0.70 for all LPH scores. The LPH Physical and Total scores discriminated between World Health Organisation (WHO) Functional classes and 6 Minute walk test distances, indicating clinical validity and were also responsive to change in clinical severity, as measured by change in WHO functional class and Borg CR 10 Scale. Further investigation is required to confirm the responsiveness of the Emotional score. Estimation of MID using distribution-based methods indicated a change of 3 points for the sub-scales and 7 for the total score to be clinically meaningful.

CONCLUSION

The LPH is a valid and reliable instrument that meets FDA criteria.

Chronic thromboembolic pulmonary hypertension: an underdiagnosed entity?

Chronic thromboembolic pulmonary hypertension (CTEPH) is the only cause of pulmonary hypertension for which there is a potential cure, which is in the form of pulmonary endarterectomy. There is a strong link between pulmonary embolism (PE) and the development of CTEPH. Although CTEPH was initially believed to be a rare complication, this belief has been reconsidered following several studies suggesting that up to 8.8% of patients develop CTEPH within the 2 years after PE. However, considering the incidence of PE, there is a significant discrepancy in the number of patients who are diagnosed, referred, and treated for CTEPH. Potential reasons for this include its often vague clinical presentation, the variable association of CTEPH with PE, and discrepancies when interpreting imaging studies. Underdiagnosis of CTEPH is preventing patients from accessing potentially curative therapy. Increased awareness about this condition is an important initial step to improving diagnostic rates and treatment.

Treatment patterns and healthcare system burden of managed care patients with suspected pulmonary arterial hypertension in the United States

OBJECTIVES

To describe treatment patterns and healthcare burden among individuals with suspected pulmonary arterial hypertension (PAH), as identified through a practice guideline-based healthcare claims algorithm.

METHODS

Adults with evidence of PAH from 1 January 2004 (commercial and Medicaid) or 1 July 2006 (Medicare Advantage) through 30 June 2008 were identified. Given the lack of an ICD-9 code for PAH, an algorithm was developed requiring: (1) ≥ 1 claim for PAH medication (index date); (2) ≥ 1 claim with a pulmonary hypertension diagnosis code in the 6-month pre-index period (baseline) or within 90 days post-index; (3) a right heart catheterization or pulmonary hypertension-related inpatient stay during baseline or within 90 days post-index; and (4) continuous health plan enrollment for 6 months pre-index and ≥ 6 months post-index. Patients with PAH-specific medications during baseline were excluded. Treatment patterns, healthcare utilization, and costs were assessed during the period ending with the earlier of health plan disenrollment or 31 December 2008.

RESULTS

Among the 521 included patients, 69% were female. Most patients (94%) initiated treatment with monotherapy (most commonly sildenafil or bosentan), and 12.7% of all patients augmented their therapy by the end of the observation period. The medication possession ratio was 0.96 each for ambrisentan (SD=0.04), bosentan (SD=0.04), and sildenafil (SD=0.05). Overall, 72.6% of patients discontinued therapy with a mean of 149 (SD=170) days until discontinuation. A mean (SD) of 2.14 (1.82) all-cause office and 1.64 (1.98) outpatient visits occurred per patient per month. Mean PAH-related healthcare costs were $6617 per patient per month, comprising 71% of all-cause costs. The guideline-based algorithm may not have perfectly captured patients with PAH.

CONCLUSIONS

Patients with suspected PAH were likely to initiate treatment with oral monotherapy, had high compliance rates, and received close ambulatory follow-up. PAH-related costs constituted the majority of all-cause healthcare costs.