Temporal Trends and Clinical Trial Characteristics Associated With the Inclusion of Women in Heart Failure Trial Steering Committees: A Systematic Review

How to make cardiology clinical trials more inclusive

Cardiovascular clinical trials continue to under-represent children, older adults, females and people from ethnic minority groups relative to population disease distribution. Here we describe strategies to foster trial representativeness, with proposed actions at the levels of trial funding, design, conduct and dissemination. In particular, trial representativeness may be increased through broad recruitment strategies and site selection criteria that reflect the diversity of patients in the catchment area, as well as limiting unjustified exclusion criteria and using pragmatic designs that minimize research burden on patients (including embedded and decentralized trials). Trial communications ought to be culturally appropriate; engaging diverse people with lived experience in the co-design of some trial elements may foster this. The demographics of trialists themselves are associated with participant demographics; therefore, trial leadership must be actively diversified. Funding bodies and journals increasingly require the reporting of sociodemographic characteristics of trial participants, and regulatory bodies now provide guidance on increasing trial diversity; these steps may increase the momentum towards change. Although this Perspective focuses on the cardiovascular trial context, many of these strategies could be applied to other fields.

Prognostic value of quality of life and functional status in patients with heart failure: a systematic review and meta-analysis

BACKGROUND

Functional health status is increasingly being recognized as a viable endpoint in heart failure (HF) trials. We sought to assess its prognostic impact and relationship with traditional clinical outcomes in patients with HF.

METHODS

MEDLINE and Cochrane central were searched up to January 2021 for post hoc analyses of trials or observational studies that assessed independent association between baseline health/functional status, and mortality and hospitalization in patients with HF across the range of left ventricular ejection fractions to evaluate the prognostic ability of NYHA class [II, III, IV], KCCQ, MLHFQ, and 6MWD. Hazard ratios (HR) with 95% confidence intervals were pooled.

RESULTS

Twenty-two studies were included. Relative to NYHA I, NYHA class II (HR 1.54 [1.16-2.04]; p < 0.01), NYHA class III (HR 2.08 [1.57-2.77]; p < 0.01), and NYHA class IV (HR 2.53 [1.25-5.12]; p = 0.01) were independently associated with increased risk of mortality. 6MWD (per 10 m) was associated with decreased mortality (HR 0.98 [0.98-0.99]; p < 0.01). A 5-point increase in KCCQ-OSS (HR 0.94 [0.91-0.96]; p < 0.01) was associated with decreased mortality. A high MLHFQ score (> 45) was significantly associated with increased mortality (HR 1.30 [1.14-1.47]; p < 0.01). NHYA class, 6MWD (per 10 m), KCCQ-OSS, and MLHFQ all significantly associated with all-cause mortality in patients with HF.

CONCLUSION

Identifying such patients with poor health status using functional health assessment can offer a complementary assessment of disease burden and trajectory which carries a strong prognostic value.

Systematic Review of Women Leading and Participating in Nephrology Randomized Clinical Trials

Introduction

Women are underrepresented in the leadership of and participation in randomized controlled trials (RCTs). We conducted a bibliometric review of nephrology RCTs to examine trial leadership by women and participation of women in nephrology RCTs.

Methods

A bibliometric review of RCTs published in top medical, surgical, or nephrology journals was conducted using MEDLINE and EMBASE from January 2011 to December 2021. Leadership by women as corresponding authors, women trial participation, and trial characteristics were examined with duplicate independent data extraction. Logistic regression was used to examine associations between trial characteristics and women leadership and trial participation.

Results

A total of 1770 studies were screened and 395 RCTs met eligibility criteria. The number (%) of women in corresponding, first, and last authorship positions were as follows: 89 (22%), 109 (28%), and 74 (19%), respectively, without change over time (P = 0.94). The median percentage (interquartile range [IQR]) of women trial participants was 39.0% (13.5%) with no difference between women or men lead authors (P = 0.15). Men lead authors were statistically less likely to enroll women in RCTs. Women lead authors were less likely to be funded by industry (odds ratio [OR]: 0.30; 95% confidence interval [CI]: 0.14-0.63; P = 0.002) or lead international trials (OR: 0.11; 95% CI: 0.01-0.83; P = 0.03). Trials with sex-specific eligibility criteria were more likely to have women leaders (OR: 2.56; 95% CI: 1.19-5.49; P = 0.02) than those without.

Discussion

Gender inequalities in RCT leadership and RCT participation exist in nephrology and did not improve over time. Strategies to improve inequalities need to be implemented and evaluated.

Exercise-based cardiac rehabilitation in women with heart failure: a review of enrollment, adherence, and outcomes

Exercise-based cardiac rehabilitation (CR) is an evidence-based recommendation for patients with stable heart failure (HF). Less clear is how effective exercise-based CR is for women with HF. The aim of this review was to synthesize the evidence for the effects of exercise-based CR on mortality, hospitalizations, exercise capacity, and quality of life (QOL) among women with HF. We identified 18 studies comprising 4917 patients, of which 1714 were women. The interventions evaluated consisted of various combinations of supervised in-hospital and out-patient sessions as well as home-based programs that included aerobic (walking, treadmill, bicycle) and resistance training. The interventions ranged from 12 to 54 weeks, with a frequency of 2-7 sessions per week, lasting from 30 to 105 min per session. Because of a paucity of sex-specific analyses of the outcomes, it was not possible to draw conclusions for women. There was limited evidence for mortality benefit for men or women participating in exercise-based CR. There was more substantial evidence for reductions in hospitalizations for the participants. Generally, exercise training improved exercise capacity. The effects of exercise-based CR on QOL were mixed with most studies favoring CR at 3 months but not at 4, 5, and 12 months. Moreover, generally, the physical dimension of QOL but not the mental dimensions improved. Recommendations for future research to reduce the gap in knowledge about the effects of exercise-based CR for women are offered.

Improving representativeness in trials: a call to action from the Global Cardiovascular Clinical Trialists Forum

Participants enrolled in cardiovascular disease (CVD) randomized controlled trials are not often representative of the population living with the disease. Older adults, children, women, Black, Indigenous and People of Color, and people living in low- and middle-income countries are typically under-enrolled in trials relative to disease distribution. Treatment effect estimates of CVD therapies have been largely derived from trial evidence generated in White men without complex comorbidities, limiting the generalizability of evidence. This review highlights barriers and facilitators of trial enrollment, temporal trends, and the rationale for representativeness. It proposes strategies to increase representativeness in CVD trials, including trial designs that minimize the research burden on participants, inclusive recruitment practices and eligibility criteria, diversification of clinical trial leadership, and research capacity-building in under-represented regions. Implementation of such strategies could generate better and more generalizable evidence to reduce knowledge gaps and position the cardiovascular trial enterprise as a vehicle to counter existing healthcare inequalities.

Dear colleagues: enough with the men-only author panels

Graphical Abstract.

A Systematic Review of Sex-Specific Reporting in Heart Failure Clinical Trials: Trial Flow and Results

Background

Females are historically underenrolled in heart failure (HF) randomized controlled trials (RCTs) relative to disease prevalence. Sex differences in trial flow, including withdrawals and losses to follow up, may further limit the generalizability of results.

Objectives

This study aimed to assess the frequency of sex-specific reporting of trial flow, treatment efficacy, and adverse events in HF RCTs.

Methods

We systematically searched MEDLINE, Embase, and CINAHL for HF RCTs published between 2000 and 2020 in journals with an impact factor ≥10. We assessed whether trial flow, treatment effect, and adverse events were disaggregated by sex. We used multivariable regression to assess associations between trial characteristics and sex subgroup analysis. We analyzed temporal trends in sex-specific reporting.

Results

We included 224 RCTs with 228,801 total participants (28.2% female). No RCT reported sex-disaggregated screening, consent, or withdrawal rates; and 2 (0.9%) reported sex-disaggregated losses to follow-up. Seventy-five RCTs (33.4%) presented sex subgroup analysis, and 63 (28.3%) reported sex-treatment interaction. No RCT reported sex-specific adverse events. Large trial size (odds ratio: 13.16, 95% CI: 5.67-30.52; P < 0.001) and device/procedure interventions (odds ratio: 5.13, 95% CI: 1.55-16.95; P < 0.007) were independently associated with sex subgroup analysis. Over the study period, there was an increase in sex subgroup analysis (P < 0.001) and testing for sex-treatment interaction (P < 0.001).

Conclusions

HF RCTs rarely reported sex differences in trial flow or adverse events and uncommonly performed sex subgroup analysis. Improved sex-disaggregated reporting could highlight the causes and extent of sex differences in trial participation and facilitate appropriate inferences about treatment effect.

Global representation of heart failure clinical trial leaders, collaborators, and enrolled participants: a bibliometric review 2000-20

AIMS

The geographic representation of investigators and participants in heart failure (HF) randomized controlled trials (RCTs) may not reflect the global distribution of disease. We assessed the geographic diversity of RCT leaders and explored associations with geographic representation of enrolled participants among impactful HF RCTs.

METHODS AND RESULTS

We searched MEDLINE, EMBASE, and CINAHL for HF RCTs published in journals with impact factor ≥ 10 between January 2000 and June 2020. We used the Jonckheere-Terpstra test to assess temporal trends and multivariable logistic regression models to explore associations between predictors and outcomes. There were 414 eligible RCTs. Only 80 of 828 trial leaders [9.7%; 95% confidence interval (CI): 7.8-11.8%] and 453 of 4656 collaborators (9.7%; 95% CI: 8.8-10.6%) were from outside Europe and North America, with no change in temporal trends and with greater disparities in large RCTs. The adjusted odds of trial leadership outside Europe and North America were lower with industry funding [adjusted odds ratio (aOR): 0.33; 95% CI: 0.15-0.75; P = 0.008]. Among 157 416 participants for whom geography was reported, only 14.5% (95% CI: 14.3-14.7%) were enrolled outside Europe and North America, but odds of enrolment were 10-fold greater with trial leadership outside Europe and North America (aOR: 10.0; 95% CI: 5.6-19.0; P < 0.001).

CONCLUSION

Regions disproportionately burdened with HF are under-represented in HF trial leadership, collaboration, and enrolment. RCT leadership outside Europe and North America is independently associated with participant enrolment in under-represented regions. Increasing research capacity outside Europe and North America could enhance trial diversity and generalizability.

Representation of women in heart failure clinical trials: Barriers to enrollment and strategies to close the gap

Heart failure is a significant public health burden that differentially impacts women. Important sex- and gender-based differences in HF risk factors, presentation, and treatment exist, and the generation of high-quality evidence is critical to elucidate these differences. Despite the remarkable growth of the heart failure clinical research enterprise over the last four decades, women remain underrepresented in heart failure clinical trials relative to the population prevalence of heart failure in women. This disparity has resulted in significant knowledge gaps regarding the optimal care of women with heart failure. In this review, we summarize the existing literature regarding the participation of women in heart failure clinical trials. Additionally, we explain the evidence surrounding sex- and gender-specific barriers to enrollment in heart failure clinical trials and describe interventions that should be implemented throughout the clinical trial lifespan to achieve sex and gender parity.

Protection by inclusion: Increasing enrollment of women in cardiovascular trials

Despite differences in biology that influence disease incidence, drug metabolism, and response to therapies, women remain under-enrolled in cardiovascular clinical trials. Estimates regarding treatment efficacy and safety are derived from male-predominant trial populations, with inadequate balance between sex subgroups for meaningful analysis on sex-specific treatment effects. Treatment strategies for women, particularly women of childbearing years, are derived from trials with predominantly men participants, from lower quality, observational studies, or anecdotal evidence. Guideline recommendations for women who are pregnant or lactating are typically based on opinion as there is little evidence to guide them. In this review, we discuss trial design factors independently associated with the under-enrollment of women, identify possible strategies to increase the enrollment of women in trials, and suggest multi-level actions that could close sex-based research disparities. Recruiting and retaining women trialists, independently associated with increased enrollment of women and Black, Indigenous, and Persons of Color (BIPOC) participants, and diversifying research teams may be effective approaches. Modifying trial design by eliminating default sex-specific exclusion criteria, developing patient-centered consent and participation processes, incorporating pragmatic follow-up schemes, and incorporating sex/gender analysis into trial planning may also increase the enrollment of women participants. Journals and funding bodies should require trials to report participant to prevalence ratios, sex-disaggregated trial flow, and sex-treatment interactions. Healthcare systems can help create research-ready cultures that both enhance patient engagement in trials and expedite end-of-trial knowledge translation.

Improving the enrollment of women and racially/ethnically diverse populations in cardiovascular clinical trials: An ASPC practice statement

Cardiovascular disease (CVD) remains the leading cause of death for both women and men worldwide. In the United States (U.S.), there are significant disparities in cardiovascular risk factors and CVD outcomes among racial and ethnic minority populations, some of whom have the highest U.S. CVD incidence and mortality. Despite this, women and racial/ethnic minority populations remain underrepresented in cardiovascular clinical trials, relative to their disease burden and population percentage. The lack of diverse participants in trials is not only a moral and ethical issue, but a scientific concern, as it can limit application of future therapies. Providing comprehensive demographic data by sex and race/ethnicity and increasing representation of diverse participants into clinical trials are essential in assessing accurate drug response, safety and efficacy information. Additionally, diversifying investigators and clinical trial staff may assist with connecting to the language, customs, and beliefs of study populations and increase recruitment of participants from diverse backgrounds. In this review, a working group for the American Society for Preventive Cardiology (ASPC) reviewed the literature regarding the inclusion of women and individuals of diverse backgrounds into cardiovascular clinical trials, focusing on prevention, and provided recommendations of best practices for improving enrollment to be more representative of the U.S. society into trials.