How Closely Do Clinical Trial Participants Resemble "Real-World" Patients with Groups 2 and 3 Pulmonary Hypertension? A Structured Review

Cluster analysis identifies novel real-world lung disease-pulmonary hypertension subphenotypes: implications for treatment response

Background

Clinical trials repurposing pulmonary arterial hypertension (PAH) therapies to patients with lung disease- or hypoxia-pulmonary hypertension (PH) (classified as World Health Organization Group 3 PH) have failed to show a consistent benefit. However, Group 3 PH clinical heterogeneity suggests robust phenotyping may inform detection of treatment-responsive subgroups. We hypothesised that cluster analysis would identify subphenotypes with differential responses to oral PAH therapy.

Methods

Two k-means analyses were performed on a national cohort of US veterans with Group 3 PH; an inclusive model (I) of all treated patients (n=196) and a haemodynamic model (H) limited to patients with right heart catheterisations (n=112). The primary outcome was organ failure or all-cause mortality by cluster. An exploratory analysis evaluated within-cluster treatment effects.

Results

Three distinct clusters of Group 3 PH patients were identified. In the inclusive model (C1I n=43, 21.9%; C2I n=102, 52.0%; C3I n=51, 26.0%), lung disease and spirometry drove cluster assignment. By contrast, in the haemodynamic model (C1H n=44, 39.3%; C2H n=43, 38.4%; C3H n=25, 22.3%), right heart catheterisation data surpassed the importance of lung disease and spirometry. In the haemodynamic model, compared to C3H, C1H experienced the greatest hazard for respiratory failure or death (HR 6.1, 95% CI 3.2-11.8). In an exploratory analysis, cluster determined treatment response (p=0.006). Conclusions regarding within-cluster treatment responses were limited by significant differences between select variables in the treated and untreated groups.

Conclusions

Cluster analysis identifies novel real-world subphenotypes of Group 3 PH patients with distinct clinical trajectories. Future studies may consider this methodological approach to identify subgroups of heterogeneous patients that may be responsive to existing pulmonary vasodilatory therapies.

Understanding the financial cost of cancer clinical trial participation

BACKGROUND

Though financial hardship is a well-documented adverse effect of standard-of-care cancer treatment, little is known about out-of-pocket costs and their impact on patients participating in cancer clinical trials. This study explored the financial effects of cancer clinical trial participation.

METHODS

This cross-sectional analysis used survey data collected in December 2022 and May 2023 from individuals with cancer previously served by Patient Advocate Foundation, a nonprofit organization providing social needs navigation and financial assistance to US adults with a chronic illness. Surveys included questions on cancer clinical trial participation, trial-related financial hardship, and sociodemographic data. Descriptive and bivariate analyses were conducted using Cramer's V to estimate the in-sample magnitude of association. Associations between trial-related financial hardship and sociodemographics were estimated using adjusted relative risks (aRR) and corresponding 95% confidence intervals (CI) from modified Poisson regression models with robust standard errors.

RESULTS

Of 650 survey respondents, 18% (N = 118) reported ever participating in a cancer clinical trial. Of those, 47% (n = 55) reported financial hardship as a result of their trial participation. Respondents reporting trial-related financial hardship were more often unemployed or disabled (58% vs. 43%; V = 0.15), Medicare enrolled (53% vs. 40%; V = 0.15), and traveled >1 h to their cancer provider (45% vs. 17%; V = 0.33) compared to respondents reporting no hardship. Respondents who experienced trial-related financial hardship most often reported expenses from travel (reported by 71% of respondents), medical bills (58%), dining out (40%), or housing needs (40%). Modeling results indicated that respondents traveling >1 h vs. ≤30 min to their cancer provider had a 2.2× higher risk of financial hardship, even after adjusting for respondent race, income, employment, and insurance status (aRR = 2.2, 95% CI 1.3-3.8). Most respondents (53%) reported needing $200-$1000 per month to compensate for trial-related expenses. Over half (51%) of respondents reported less willingness to participate in future clinical trials due to incurred financial hardship. Notably, of patients who did not participate in a cancer clinical trial (n = 532), 13% declined participation due to cost.

CONCLUSION

Cancer clinical trial-related financial hardship, most often stemming from travel expenses, affected almost half of trial-enrolled patients. Interventions are needed to reduce adverse financial participation effects and potentially improve cancer clinical trial participation.

Real-world use of inhaled treprostinil for lung disease-pulmonary hypertension: A protocol for patient evaluation and prescribing

Inhaled treprostinil was approved recently for interstitial lung disease-pulmonary hypertension; however, efficacy in "real-world" populations is not known. We designed a protocol and report our experience evaluating 10 patients referred for therapy. Misdiagnosis at presentation was common; ultimately, three patients (30%) were prescribed drug. This protocol offers an opportunity to standardize longitudinal assessment of inhaled treprostinil in clinical practice.

Demographic and Health Behavior Factors Associated With Clinical Trial Invitation and Participation in the United States

IMPORTANCE

Representative enrollment in clinical trials is critical to ensure equitable and effective translation of research to practice, yet disparities in clinical trial enrollment persist.

OBJECTIVE

To examine person-level factors associated with invitation to and participation in clinical trials.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study analyzed responses from 3689 US adults who participated in the nationally representative Health Information National Trends Survey, collected February through June 2020 via mailed questionnaires.

EXPOSURES

Demographic, clinical, and health behavior-related characteristics.

MAIN OUTCOMES AND MEASURES

History of invitation to and participation in a clinical trial, primary information sources, trust in information sources, and motives for participation in clinical trials were described. Respondent characteristics are presented as absolute numbers and weighted percentages. Associations between respondent demographic, clinical, and health behavior-related characteristics and clinical trial invitation and participation were estimated using survey-weighted logistic regression models.

RESULTS

The median (IQR) age of the 3689 respondents was 48 (33-61) years, and most were non-Hispanic White individuals (2063 [59%]; non-Hispanic Black, 452 [10%]; Hispanic, 521 [14%]), had more than a high school degree (2656 [68%]), were employed (1809 [58%]), and had at least 1 medical condition (2535 [61%]). Overall, 439 respondents (9%) had been invited to participate in any clinical trial. Respondents with increased odds of invitation were non-Hispanic Black compared with non-Hispanic White (adjusted odds ratio [aOR], 1.85; 95% CI, 1.13-3.02), had greater than a high school education compared with less than high school education (eg, ≥college degree: aOR, 4.84; 95% CI, 1.89-12.39), were single compared with married or living as married (aOR, 1.68; 95% CI, 1.04-2.73), and had at least 1 medical condition compared to none (eg, 1 medical condition: aOR, 2.25; 95% CI, 1.32-3.82). Respondents residing in rural vs urban areas had 77% decreased odds of invitation to a clinical trial (aOR 0.33; 95% CI 0.17-0.65). Of invited respondents, 199 (47%) participated. Compared with non-Hispanic White respondents, non-Hispanic Black respondents had 72% decreased odds of clinical trial participation (aOR, 0.28; 95% CI, 0.09-0.87). Respondents most frequently reported "health care providers" as the first and most trusted source of clinical trial information (first source: 2297 [59%]; most trusted source: 2597 [70%]). The most frequently reported motives for clinical trials participation were "wanting to get better" (2294 [66%]) and the standard of care not being covered by insurance (1448 [41%]).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that invitation to and participation in clinical trials may differ by person-level demographic and clinical characteristics. Strategies toward increasing trial invitation and participation rates across diverse patient populations warrant further research to ensure equitable translation of clinical benefits from research to practice.

Outcomes of pulmonary vasodilator use in Veterans with pulmonary hypertension associated with left heart disease and lung disease

Randomized trials of pulmonary vasodilators in pulmonary hypertension due to left heart disease (Group 2) and lung disease (Group 3) have demonstrated potential for harm. Yet these therapies are commonly used in practice. Little is known of the effects of treatment outside of clinical trials. We aimed to establish outcomes of vasodilator treatment for Groups 2/3 pulmonary hypertension in real-world practice. We conducted a retrospective cohort study of 132,552 Medicare-eligible Veterans with incident Groups 2/3 pulmonary hypertension between 2006 and 2016, and a secondary nested case-control study. Our primary outcome was a composite of death by any cause or selected acute organ failures. In our cohort analysis, we calculated adjusted risks of time to our outcome using Cox proportional hazards models with facility-specific random effects. In our case-control analysis, we used logistic mixed-effects models to estimate the effect of any past, recent, and cumulative exposure on our outcome. From our cohort study, 3249 (2.5%) Veterans were exposed to pulmonary vasodilators. Exposure to vasodilators was associated with increased risk of our primary outcome, in both Group 3 (HR: 1.58 (95% CI: 1.37-1.82)) and Group 2 (HR: 1.26 (95% CI: 1.12-1.41)) pulmonary hypertension patients. The case-control study determined odds of our outcome increased by 11% per year of exposure (OR: 1.11 (95% CI: 1.07-1.16)). Treating Groups 2/3 pulmonary hypertension with vasodilators in clinical practice is associated with increased risk of harm. This extension of trial findings to a real-world setting offers further evidence to limit use of vasodilators in Groups 2/3 pulmonary hypertension outside of clinical trials.