The impact of cardiovascular disease prevalence on women's enrollment in landmark randomized cardiovascular trials: a systematic review

Sex distribution in clinical trials of radiologic contrast agents: A 27-year review

PURPOSE

Clinical trials play a pivotal role in assessing the safety and efficacy of medical therapies. Addressing sex distribution among enrollees in clinical trials of radiologic contrast agents is essential for ensuring the generalizability of trial outcomes. Previous research has highlighted the influence of demographic factors, particularly sex, on treatment responses, emphasizing the need for equitable representation in clinical trials. Our study aim was to determine the sex distribution of enrollees in clinical trials of radiologic contrast agents.

METHODS

Our retrospective study included a total of 65 clinical trials conducted between 1990 and 2017 identified on clinicaltrials.gov after a comprehensive review including searching individually for all FDA approved contrast agents. Data collected included the year of FDA approval, the number of participants, sex distribution, trial location, trial phase, and study type. Inter-rater validation ensured data accuracy.

RESULTS

Our analysis revealed fluctuations in sex distribution of trial enrollees. Enrollment of males exceeded females in most years, with a shift towards a more equitable representation in recent trials. Trials conducted in the United States had a higher rate of enrollment by females. Phase I trials had the most balanced representation, whereas Phase IV trials had the highest sex disparity.

CONCLUSION

Across all trials, females made up 47.3 % of enrollees [3316 out of 7016 total enrollees]. Enrollment of males exceeded females in 44 of the 65 trials studied, females outnumbered males in 19 trials, and enrollment was equal between the sexes in 2 trials. While the sex distribution observed across all trials represents an equitable representation of enrollees, the wide variance of sex distribution at the level of individual trials has the potential to limit the generalizability of results.

Temporal Trends of Enrollment by Sex and Race in Major Cardiovascular Randomized Clinical Trials

Background

Women and racialized minorities continue to be underrepresented in cardiovascular (CV) trial outcomes data, despite comprising a significant global burden of CV disease. This study evaluated the impact of trial characteristics on the temporal enrollment of women and racialized minorities in prominent CV trials published in the period 1986-2023.

Methods

MEDLINE was searched for CV trials published in The Lancet, the Journal of the American Medical Association, and the New England Journal of Medicine. Participant and investigator demographics, types of interventions, clinical indications, and funding sources were compared according to the enrollment of women or racialized minorities.

Results

From 799 studies, including 4,071,921 patients, the enrollment of women and racialized minorities significantly increased from 1986 to 2023 (both P ≤ 0.001). Although the enrollment of women varied by trial indication, comprising 25.0% of coronary artery disease, 35.2% of noncoronary and/or vascular disease, 13.8% of heart failure, 17.0% of arrhythmia, and 28.7% of other CV trials (P ≤ 0.001), it did not differ by peer-reviewed vs industry funding. First authors who were women were more likely than first authors who were men to enroll significantly more women (P = 0.01).

Conclusions

Active efforts to increase diverse enrollment, along with improved reporting, including of sex and race, in future CV trials may increase the generalizability of their findings and applicability to global populations.

Analysis of Gender-Based Inequality in Cardiovascular Health: An Umbrella Review

This umbrella review aims to investigate possible gender-based inequality in cardiovascular health and improve understanding surrounding differing presentations seen in women. Searches of current literature were conducted using Medline; Cochrane; Cumulative Index of Nursing and Allied Health Literature (CINAHL Plus); and PubMed databases. Focusing on systematic reviews and meta-analyses from the last decade, searches were expanded to the publication year of 2000 onwards, to enable a broader review of current practices. Current clinical guidelines were also reviewed. 17 articles were deemed to satisfy the desired criteria and were therefore carried forward to be critically appraised. The articles reviewed were multifactorial; however, they can be grouped into four categories of common focus: risk factors, presentation, treatment, and current research. On critical analysis, 13 reoccurring themes were noted throughout the reviewed articles with each discussed in detail within this review. There is a need to prioritize women in cardiovascular health, through raising awareness, improving prevention (both primary and secondary), reducing delays in presentation, and increasing understanding and recognition of sex differences in symptom presentation, to enable improved diagnosis and treatment along with the standardization of gender-specific clinical guidance. The results are unanimous regarding an undeniable gender-based inequality in cardiovascular health to the detriment of women. With such damning evidence that women are under-represented and indeed undertreated, the time has come now to question whether women should be considered as their own specialty within cardiology and to ultimately raise awareness and ensure women are given the same consideration regarding cardiovascular disease (CVD) risk assessment and treatment, in order to finally remove gender inequality in cardiovascular (CV) health. In order to reverse this disparity, it is clear from the included studies that further research is required to understand the sex differences seen in both the presentation and symptoms of CVD as well as to enable improved treatment of women and the development of sex-specific strategies and clinical guidance to empower clinicians moving forward.

Underrepresentation of women in randomized controlled trials: a systematic review and meta-analysis

BACKGROUND

Although regulatory changes towards correcting the underrepresentation of women in randomized controlled trials (RCTs) occurred (National Institutes of Health 1994), concerns exist about whether an improvement is taking place. In this systematic review and meta-analysis, we aimed to assess the inclusion rates of women in recent RCTs and to explore the potential barriers for the enrollment of women.

METHODS

RCTs published in 2017 examining any type of intervention in adults were searched in PubMed and Cochrane Library. The following predefined medical fields were included: cardiovascular diseases, neoplasms, endocrine system diseases, respiratory tract diseases, bacterial and fungal infections, viral diseases, digestive system diseases, and immune system diseases. Studies were screened independently by two reviewers, and an equal number of studies was randomly selected per calendric month. The primary outcome was the enrollment rate of women, calculated as the number of randomized women patients divided by the total number of randomized patients. Rates were weighted by their inverse variance; statistical significance was tested using general linear models (GLM).

RESULTS

Out of 398 RCTs assessed for eligibility, 300 RCTs were included. The enrollment rate of women in all the examined fields was lower than 50%, except for immune system diseases [median enrollment rate of 68% (IQR 46 to 81)]. The overall median enrollment rate of women was 41% (IQR 27 to 54). The median enrollment rate of women decreased with older age of the trials' participants [mean age of trials' participants ≤ 45 years: 47% (IQR 30-64), 46-55 years: 46% (IQR 33-58), 56-62 years: 38% (IQR 27-50), ≥ 63 years: 33% (IQR 20-46), p < 0.001]. Methodological quality characteristics showed no significant association with the enrollment rates of women. Out of the 300 included RCTs, eleven did not report on the number of included women. There was no significant difference between these studies and the studies included in the analysis.

CONCLUSIONS

Women are being inadequately represented, in the selected medical fields analyzed in our study, in recent RCTs. Older age is a potential barrier for the enrollment of women in clinical trials. Low inclusion rates of elderly women might create a lack of crucial knowledge in the adverse effects and the benefit/risk profile of any given treatment. Factors that might hinder the participation of women should be sought and addressed in the design of the study.

The representation of females in clinical trials for substance use disorder conducted in the United States (2010-19)

BACKGROUND AND AIMS

Women have historically been under-represented in clinical research, but the extent to which this is true for substance use disorder (SUD) trials is unknown. We aimed to determine the ratio of female:male participation in clinical trials for SUDs and describe the reporting of sex-specific outcomes from 2010 to 2019.

DESIGN

A retrospective cohort review of clinical trials involving people with SUD.

SETTING

United States.

PARTICIPANTS

Clinical trials including people with SUD registered in clinicaltrials.gov and completed between 1 January 2010 and 31 December 2019 were reviewed. Trials were excluded if they had < 30 participants, focused on SUD prevention, were conducted outside the United States and/or did not report data on participant sex or gender.

MEASUREMENTS

The following were extracted for each trial: primary outcome, number of participants enrolled, analytical sample size, percentage of participants who were female, inclusion of transgender participants, whether sex-based analyses were performed, funding source, type of SUD and type of intervention. Relative representation in trials was examined using the female:male ratio, reported using median ratios and by year of trial completion. The proportion of females participating was adjusted using the underlying disease prevalence among females using National Survey on Drug Use and Health data.

FINDINGS

A total of 316 trials met inclusion criteria: 274 were mixed-sex, 12 enrolled only males and 30 only females. In 274 mixed-sex trials, 40% of 57 544 participants were female. Only 22 trials (8%) reported any sex-specific analyses; four studies (1.5%) reported inclusion of transgender participants. Females represented 35% of participants in trials targeting illicit drug use disorder, 52% in nicotine use disorder and 29% in alcohol use disorder. Accounting for underlying disease prevalence revealed that women had the lowest relative enrollment in alcohol use disorder trials (median participation to prevalence ratio in 2017: 0.58; 95% confidence interval: 0.13, 0.91).

CONCLUSIONS

A review of 316 US clinical trials for alcohol, nicotine and illicit substance use disorders completed between 2010 and 2019 showed that females were enrolled at lower rates than males overall. Only 8% of the trials reviewed reported sex-specific analyses and 1.5% reported transgender participants.

Distinct pathophysiological pathways in women and men with heart failure

AIMS

Clinical differences between women and men have been described in heart failure (HF). However, less is known about the underlying pathophysiological mechanisms. In this study, we compared multiple circulating biomarkers to gain better insights into differential HF pathophysiology between women and men.

METHODS AND RESULTS

In 537 women and 1485 men with HF, we compared differential expression of a panel of 363 biomarkers. Then, we performed a pathway over-representation analysis to identify differential biological pathways in women and men. Findings were validated in an independent HF cohort (575 women, 1123 men). In both cohorts, women were older and had higher left ventricular ejection fraction (LVEF). In the index and validation cohorts respectively, we found 14/363 and 12/363 biomarkers that were relatively up-regulated in women, while 21/363 and 14/363 were up-regulated in men. In both cohorts, the strongest up-regulated biomarkers in women were leptin and fatty acid binding protein-4, compared to matrix metalloproteinase-3 in men. Similar findings were replicated in a subset of patients from both cohorts matched by age and LVEF. Pathway over-representation analysis revealed increased activity of pathways associated with lipid metabolism in women, and neuro-inflammatory response in men (all p &lt; 0.0001).

CONCLUSION

In two independent cohorts of HF patients, biomarkers associated with lipid metabolic pathways were observed in women, while biomarkers associated with neuro-inflammatory response were more active in men. Differences in inflammatory and metabolic pathways may contribute to sex differences in clinical phenotype observed in HF, and provide useful insights towards development of tailored HF therapies.

Best Practices for Designing Informative Trials Including Women

PURPOSE OF REVIEW

Despite mandates from funding agencies and professional societies to broaden inclusivity in medical research, women remain underrepresented in cardiovascular clinical trials. This lack of representation limits the generalizability of the findings and results in uncertainty about the safety and efficacy of many cardiovascular therapies in female patients.

RECENT FINDINGS

Several barriers impact women's participation in clinical trials, including enrollment criteria, common misconceptions, access to tertiary care, and women representation in clinical trial leadership. This short review discusses these barriers and suggests potential solutions to increase women's participation in clinical trials and improve their cardiovascular health.

Underrepresentation of women in cardiovascular trials- it is time to shatter this glass ceiling

Cardiovascular disease (CVD) is the leading cause of death in women, with underrepresented minority (URM) women experiencing the highest mortality rate. For decades, there has been an underrepresentation of women in CVD trials. Although more recent studies have increased the number of women enrolled in these trials, systematic reviews have demonstrated that this enrollment is still low. The National Institute of Health along with other agencies have boosted their efforts to increase enrollment of women and URM populations in CVD trials. Despite these efforts, there still remains a gap. This paper reviews the magnitude, implications and causes of the underrepresentation of women in CVD trials. A proposed multifaceted approach to solving this issue is also outlined in this commentary. Hopefully, implementation of these proposed solutions may facilitate the increase of women, including URM women, enrolled in CVD trials. It is anticipated that this will improve CVD outcomes in these patients.

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.

Representation of Women in Stroke Clinical Trials: A Review of 281 Trials Involving More Than 500,000 Participants

BACKGROUND AND OBJECTIVES

Women have been underrepresented in cardiovascular disease clinical trials but there is less certainty over the level of disparity specifically in stroke. We examined the participation of women in trials according to stroke prevalence in the population.

METHODS

Published randomized controlled trials with ≥100 participants enrolled between 1990 and 2020 were identified from ClinicalTrials.gov. To quantify sex disparities in enrollment, we calculated the participation to prevalence ratio (PPR), defined as the percentage of women participating in a trial vs the prevalence of women in the disease population.

RESULTS

There were 281 stroke trials eligible for analyses with a total of 588,887 participants, of whom 37.4% were women. Overall, women were represented at a lower proportion relative to their prevalence in the underlying population (mean PPR 0.84; 95% confidence interval [CI] 0.81-0.87). The greatest differences were observed in trials of intracerebral hemorrhage (PPR 0.73; 95% CI 0.71-0.74), trials with a mean age of participants <70 years (PPR 0.81; 95% CI 0.78-0.84), nonacute interventions (PPR 0.80; 95% CI 0.76-0.84), and rehabilitation trials (PPR 0.77; 95% CI 0.71-0.83). These findings did not significantly change over the period from 1990 to 2020 (p for trend = 0.201).

DISCUSSION

Women are disproportionately underrepresented in stroke trials relative to the burden of disease in the population. Clear guidance and effective implementation strategies are required to improve the inclusion of women and thus broader knowledge of the impact of interventions in clinical trials.

The effect of sex on door-to-balloon time in patients presenting with ST-elevation myocardial infarction and referred for primary percutaneous coronary intervention: A systematic review

Timely reperfusion using primary percutaneous coronary intervention (pPCI) is the cornerstone of acute ST-elevation myocardial infarction (STEMI) management. We conducted a systematic review to examine the effect of sex on door-to-balloon (D2B) time and symptom-to-balloon (S2B) time. We observed longer D2B times and S2B times in female patients presenting with STEMI and referred for pPCI when compared to male patients. Future work is required to try and elucidate and mitigate sex-based front-line treatment delays for female STEMI patients.

Disparities in Cardiovascular Care and Outcomes for Women From Racial/Ethnic Minority Backgrounds

Purpose of review

Racial, ethnic, and gender disparities in cardiovascular care are well-documented. This review aims to highlight the disparities and impact on a group particularly vulnerable to disparities, women from racial/ethnic minority backgrounds.

Recent findings

Women from racial/ethnic minority backgrounds remain underrepresented in major cardiovascular trials, limiting the generalizability of cardiovascular research to this population. Certain cardiovascular risk factors are more prevalent in women from racial/ethnic minority backgrounds, including traditional risk factors such as hypertension, obesity, and diabetes. Female-specific risk factors including gestational diabetes and preeclampsia as well as non-traditional psychosocial risk factors like depressive and anxiety disorders, increased child care, and familial and home care responsibility have been shown to increase risk for cardiovascular disease events in women more so than in men, and disproportionately affect women from racial/ethnic minority backgrounds. Despite this, minimal interventions to address differential risk have been proposed. Furthermore, disparities in treatment and outcomes that disadvantage minority women persist. The limited improvement in outcomes over time, especially among non-Hispanic Black women, is an area that requires further research and active interventions.

Summary

Understanding the lack of representation in cardiovascular trials, differential cardiovascular risk, and disparities in treatment and outcomes among women from racial/ethnic minority backgrounds highlights opportunities for improving cardiovascular care among this particularly vulnerable population.

Trial characteristics associated with under-enrolment of females in randomized controlled trials of heart failure with reduced ejection fraction: a systematic review

AIMS

To evaluate temporal trends in the enrolment of females in randomized controlled trials (RCTs) of heart failure with reduced ejection fraction (HFrEF) published in high-impact journals, and assess RCT characteristics associated with under-enrolment.

METHODS AND RESULTS

We searched MEDLINE, EMBASE and CINAHL for studies published from January 2000 to May 2019 in journals with impact factor ≥10. We included RCTs that recruited adults with HFrEF. We used a 20% threshold below the sex distribution of HFrEF to define under-enrolment. We used multivariable logistic regression to assess trial characteristics independently associated with under-enrolment. We included 317 RCTs. Among the 183 097 participants, mean (standard deviation) age was 63.0 (7.0) years and 25.5% were female. Females were under-enrolled in 71.6% [95% confidence interval (CI) 66.6-76.6%] of the RCTs; enrolment did not increase significantly between 2000-2019. Sex-related eligibility criteria [odds ratio (OR) 2.05, 95% CI 1.01-4.16; P = 0.046]; recruitment in ambulatory settings (OR 2.56, 95% CI 1.37-4.81; P = 0.003); trial coordination in North America (OR 4.44, 95% CI 1.09-18.07; P = 0.037), Europe (OR 6.79, 95% CI 1.63-27.39; P = 0.018) and Asia (OR 9.33, 95% CI 1.40-12.40; P = 0.033); drug (OR 1.76, 95% CI 1.96-7.36; P < 0.001) and device/surgical interventions (OR 1.69, 95% CI 1.16-9.43; P = 0.002); and men in first and last authorship position (OR 1.32, 95% CI 1.12-3.54; P = 0.047) were associated with under-enrolment of females.

CONCLUSIONS

Females were under-enrolled relative to disease distribution in a majority of high-impact HFrEF RCTs, with no change in temporal trends between 2000 and 2019. Trial characteristics and gender of trial leaders were associated with under-enrolment.

Women’s Cardiac Health in 2020: A Systematic Review

Although substantial progress has been made toward improving gender- and sex-specific cardiovascular disease (CVD) management and outcomes, contemporary reports indicate a persistent knowledge gap with regard to optimal risk-stratification and management in female cardiac heart disease (CHD) patients. Prominent patient and system delays in diagnosing CHD are, in part, due to the limited awareness for the latent CVD risk in women, a lack of sex-specific thresholds within clinical guidelines, and subsequent limited performance of contemporary diagnostic approaches in women. Several traditional risk factors for CHD affect both women and men. But other factors can play a bigger role in the development of heart disease in women. In addition, little is known about the influence of socioenvironmental and contextual factors on gender-specific disease manifestation and outcomes. It is imperative that we understand the mechanisms that contribute to worsening risk factors profiles in young women to reduce future atherosclerotic CVD morbidity and mortality. This comprehensive review focuses on the novel aspects of cardiovascular health in women and sex differences as they relate to clinical practice and prevention, diagnosis, and treatment of CVD. Increased recognition of the prevalence of traditional cardiovascular risk factors and their differential impact in women, as well as emerging nontraditional risk factors unique to or more common in women, contribute to new understanding mechanisms, leading to worsening outcome for women.

Sex-specific efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation: An individual patient data meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a growing health burden, and pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) represents an attractive therapeutic option. Sex-specific differences in the epidemiology, pathophysiology, and clinical presentation of AF and PVI are recognized.

OBJECTIVE

We aimed at comparing the efficacy, safety, and procedural characteristics of CB and RF in women and men undergoing a first PVI procedure.

METHODS

We searched for randomized controlled trials and prospective observational studies comparing CB and RF ablation with at least 1 year of follow-up. After merging individual patient data from 18 data sets, we investigated the sex-specific (procedure failure defined as recurrence of atrial arrhythmia, reablation, and reinitiation of antiarrhythmic medication), safety (periprocedural complications), and procedural characteristics of CB vs RF using Kaplan-Meier and multilevel models.

RESULTS

From the 18 studies, 4840 men and 1979 women were analyzed. An analysis stratified by sex correcting for several covariates showed a better efficacy of CB in men (hazard ratio for recurrence 0.88; 95% confidence interval 0.78-0.98, P = .02) but not in women (hazard ratio 0.98; 95% confidence interval 0.83-1.16; P = .82). For women and men, the energy source had no influence on the occurrence of at least 1 complication. For both sexes, the procedure time was significantly shorter with CB (-22.5 minutes for women and -27.1 minutes for men).

CONCLUSION

CB is associated with less long-term failures in men. A better understanding of AF-causal sex-specific mechanisms and refinements in CB technologies could lead to higher success rates in women.

Women’s Participation in Cardiovascular Clinical Trials From 2010 to 2017

Background:

Cardiovascular disease is the leading cause of death among women worldwide, yet, women have historically been underrepresented in cardiovascular trials.

Methods:

We systematically assessed the participation of women in completed cardiovascular trials registered in ClinicalTrials.gov between 2010 and 2017, and extracted publicly available information including disease type, sponsor type, country, trial size, intervention type, and the demographic characteristics of trial participants. We calculated the female-to-male ratio for each trial and determined the prevalence-adjusted estimates for participation of women by dividing the percentage of women among trial participants by the percentage of women in the disease population (participation prevalence ratio; a ratio of 0.8 to 1.2 suggests comparable prevalence and good representation).

Results:

We identified 740 completed cardiovascular trials including a total of 862 652 adults, of whom 38.2% were women. The median female-to-male ratio of each trial was 0.51 (25th quartile, 0.32; 75th quartile, 0.90) overall and varied by age group (1.02 in ≤55 year old group versus 0.40 in the 61- to 65-year-old group), type of intervention (0.44 for procedural trials versus 0.78 for lifestyle intervention trials), disease type (0.34 for acute coronary syndrome versus 3.20 for pulmonary hypertension), region (0.45 for Western Pacific versus 0.55 for the Americas), funding/sponsor type (0.14 for government-funded versus 0.73 for multiple sponsors), and trial size (0.56 for smaller [n≤47] versus 0.49 for larger [n≥399] trials). Relative to their prevalence in the disease population, participation prevalence ratio was higher than 0.8 for hypertension, pulmonary arterial hypertension and lower (participation prevalence ratio 0.48 to 0.78) for arrhythmia, coronary heart disease, acute coronary syndrome, and heart failure trials. The most recent time period (2013 to 2017) saw significant increases in participation prevalence ratios for stroke ( P =0.007) and heart failure ( P =0.01) trials compared with previous periods.

Conclusions:

Among cardiovascular trials in the current decade, men still predominate overall, but the representation of women varies with disease and trial characteristics, and has improved in stroke and heart failure trials.

The impact of sex and age on T cell immunity and ischemic stroke outcomes

Sex differences are well-recognized in ischemic stroke, a disease mainly affecting the elderly. Stroke results in robust activation of central and peripheral immune responses which contributes to functional outcome. Aging is associated with increased low-grade chronic inflammation known as "inflammaging" that renders aged males and females more susceptible to poor outcomes after ischemic stroke. Despite the fact that sex differences are well-documented in immunity and inflammation, few studies have focused on sex differences in inflammatory responses after ischemic stroke and even fewer have been performed in the context of aging. The role of T cell responses in ischemic stroke have gained increasing attention over the past decade as data suggest a major role in the pathophysiology/recovery after ischemic injury. T cells offer an attractive therapeutic target due to their relatively delayed infiltration into the ischemic brain. This review will focus on T cell immune responses in ischemic stroke, highlighting studies examining the effects of aging and biological sex.

Participation of Women in Clinical Trials Supporting FDA Approval of Cardiovascular Drugs

BACKGROUND

Concerns exist that women are underrepresented in trials of cardiovascular medications.

OBJECTIVES

The authors sought to examine women's participation and the reported safety and efficacy by gender for pivotal cardiovascular disease (CVD) trials submitted to the U.S. Food and Drug Administration (FDA) supporting marketing applications.

METHODS

On the basis of publicly available FDA reviews, the authors assessed enrollment of women in trials supporting 36 drug approvals from 2005 to 2015. Prevalence-corrected estimates for the participation of women were calculated as the percentage of women among trial participants divided by the percentage of women in the disease population (participation to prevalence ratio [PPR]), with a range between 0.8 and 1.2 reflecting similar representation of women in the trial and disease population. Sex differences in efficacy and safety were assessed.

RESULTS

The proportion of women enrolled ranged from 22% to 81% (mean 46%). The calculated PPR by disease area was within or above the desirable range for atrial fibrillation (0.8 to 1.1), hypertension (0.9), and pulmonary arterial hypertension (1.4); PPR was <0.8 for heart failure (0.5 to 0.6), coronary artery disease (0.6), and acute coronary syndrome/myocardial infarction (0.6). The authors found little indication of clinically meaningful gender differences in efficacy or safety. Gender differences in efficacy or safety were described in labeling for 4 drugs.

CONCLUSIONS

Women were well represented in trials of drugs for hypertension and atrial fibrillation, and overrepresented for pulmonary arterial hypertension. Representation of women fell below a PPR of 0.8 for trials in heart failure, coronary artery disease, and acute coronary syndrome. Minimal gender differences in drug efficacy and safety profiles were observed.

Sex-specific efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a growing healthcare burden, for which pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) represent attractive therapies. Women are at higher risk of recurrence after AF ablation and present a specific complications profile. Therefore, a systematic catheter-specific assessment of pulmonary vein isolation is urgently needed in women.

OBJECTIVE

Systematically assessing the sex-specific efficacy/safety of CB vs RF ablation.

METHODS

We performed a structured database search of the scientific literature for randomized controlled trials (RCTs) and observational prospective studies (OPS) comparing CB and RF ablation efficacy at 1 year. We investigated the reporting of sex-specific analyses and assessed the comparative sex-specific efficacy, safety and procedural characteristics of CB vs RF using random-effect meta-regression accounting for the proportion of enrolled women.

RESULTS

Twenty-three studies were included (18 OPS and 5 RCTs) for a total of 13 509 patients. Sex-specific outcomes by ablation device were reported in two and sex-specific regression in four studies, none of which took the ablation device into account. Meta-regression accounting for the proportion of enrolled women showed no significant difference in outcomes between RF or CB.

CONCLUSION

The sex-specific reporting in trials comparing CB to RF is extremely low. A quantitative meta-regression using the percentage of enrolled women as sex-specific indicator did not show any difference between CB and RF but acknowledging the low percentage of enrolled women and the lack of sex-specific data, further research including patient-level data is urgently needed to draw more definitive conclusions.

Enrollment and Retention of Men and Women in Health Services Research and Development Trials

INTRODUCTION

Sex- and gender-specific science is essential to inform patient-centered, evidence-based care. Developing such evidence requires adequate inclusion of both women and men in trials. We sought to describe study participation of women and men in Department of Veterans Affairs Health Services Research and Development trials.

METHODS

We identified recent health services research trials from one Health Services Research and Development Center of Innovation and compared the participation of women and men from trial recruitment to study completion. We also calculated the participation to prevalence ratio (PPR) by sex for each trial.

RESULTS

We included eight trials that started recruitment between 2011 and 2014. Only one study purposefully attempted to boost the recruitment of women. Overall, the PPR for women ranged from 0.2 to 4.5, with seven studies having a PPR of greater than 1, indicating that women participated in these trials at proportions greater than their prevalence in the disease population within the Department of Veterans Affairs. The PPR for men ranged from 0.8 to 1.1. Retention was best with those studies that used administrative data for final outcomes assessment. No studies provided results stratified by sex or conducted analyses to explore treatment effect by sex.

CONCLUSIONS

At a single site, women participated in Health Services Research and Development trials at similar or greater rates to men without cross-study efforts to enrich the recruitment or retention of women. Adding strategic recruitment approaches could further boost the proportion of women in Department of Veterans Affairs trials and enable adequately powered sex-based analyses.

Gender differences in clinical registration trials: is there a real problem?

AIMS

Several studies have reported the under-representation of women in clinical trials, thereby challenging the external validity of the benefit/risk assessments of launched drugs. Our aim was to determine the extent to which women have been included in clinical trials used for drug registration and to analyse the fraction of women participating in phases I, II and III.

METHODS

We conducted cross-sectional, structured research into publicly available registration dossiers of Food and Drug Administration (FDA)-approved drugs that are prescribed frequently. Furthermore, we analysed compounds with high hepatic clearance and a known gender-related difference in drug response. In a sensitivity analysis, we compared figures with US disease prevalence data.

RESULTS

For 38 of the initial 137 drugs (28%), sufficient data were reported and publicly available. For these drugs, 185 479 trial participants were included, of whom 47% were female and 44% were male; gender was not reported for 9% of participants. However, the number of female participants varied with the phase of the trial, with 22% females in phase I trials vs. 48% and 49%, respectively, in phase II and III trials. When compared with US disease prevalence data, 10 drugs (26%) had a greater than 20% difference between the proportion of females affected with the disease compared with representation in clinical trials.

CONCLUSIONS

From these publicly available data, there was no evidence of any systematic under-representation of women in clinical trials.

A Patient Presents with Longstanding, Severe LV Dysfunction. Is There a Role for Additional Risk Stratification Before ICD?

Increased longevity of patients with systolic heart failure caused by the use of implantable cardioverter-defibrillators (ICDs) is one of the most successful achievements in contemporary medicine. During the last 2 decades, the scientific community has striven to increase the benefits of ICD usage by specifying indications for primary prevention ICD implantation. Left ventricular ejection fraction is neither highly specific nor is it a highly sensitive risk marker of sudden cardiac death. The authors discuss risk-stratification approaches in different patient populations with structural heart disease and systolic heart failure.

Women, the menopause, hormone replacement therapy and coronary heart disease

PURPOSE OF REVIEW

Cardiovascular disease considerations are associated with the menopause. Despite a misconception that women have a minimal risk for coronary heart disease (CHD), it is the major cause of female deaths. This review highlights issues of hormone replacement therapy (HRT) and CHD in women.

RECENT FINDINGS

A woman under age 60, who suffers a myocardial infarction (MI), has a 2-year post-MI mortality of 28.9%; it is 19.6% in men. CHD and MI in women are subtle. In addition, female mortality from CHD increases after the menopause. The increased inflammatory risk factor status of women plays a role in development of atherosclerosis, before and after the menopause. Until after the menopause, women overall have a lower CHD mortality rate. Menopause is associated with unique symptoms, especially vasomotor ones; preexisting cardiovascular disease further exacerbates problems associated with the menopause. Use of HRT after the menopause is a major issue. Early menopause at age 39 years or younger and late menopause at age 56 years or older increase cardiovascular risk. HRT should not be prescribed for cardiovascular risk prevention, but when less than 10 years from menopause at a normal age, women can be reassured that cardiovascular risk from HRT is very low.

SUMMARY

Prescription of HRT should never be made only for cardiovascular risk reduction. However, when symptom-related and other indications are present, HRT is appropriate and well tolerated in the early years after menopause with onset at a normal age.

What is the extent and quality of documentation and reporting of fidelity to implementation strategies: a scoping review

BACKGROUND

Implementation fidelity is critical to the internal and external validity of implementation research. Much of what is written about implementation fidelity addresses fidelity of evidence-informed interventions rather than fidelity of implementation strategies. The documentation and reporting of fidelity to implementation strategies requires attention. Therefore, in this scoping review, we identify the extent and quality of documentation and reporting of fidelity of implementation strategies that were used to implement evidence-informed interventions.

METHODS

A six-stage methodological framework for scoping studies guided our work. Studies were identified from the outputs of the Effective Practice and Organization of Care (EPOC) review group within the Cochrane Database of Systematic Reviews. EPOC's primary focus, implementation strategies influencing provider behavior change, optimized our ability to identify articles for inclusion. We organized the retrieved articles from the systematic reviews by journal and selected the three journals with the largest number of retrieved articles. Using a data extraction tool, we organized retrieved article data from these three journals. In addition, we summarized implementation strategies using the EPOC categories. Data extraction pertaining to the quality of reporting the fidelity of implementation strategies was facilitated with an "Implementation Strategy Fidelity Checklist" based on definitions adapted from Dusenbury et al. We conducted inter-rater reliability checks for all of the independently scored articles. Using linear regression, we assessed the fidelity scores in relation to the publication year.

RESULTS

Seventy-two implementation articles were included in the final analysis. Researchers reported neither fidelity definitions nor conceptual frameworks for fidelity in any articles. The most frequently employed implementation strategies included distribution of education materials (n = 35), audit and feedback (n = 32), and educational meetings (n = 25). Fidelity of implementation strategies was documented in 51 (71 %) articles. Inter-rater reliability coefficients of the independent reviews for each component of fidelity were as follows: adherence = 0.85, dose = 0.89, and participant responsiveness = 0.96. The mean fidelity score was 2.6 (SD = 2.25). We noted a statistically significant decline in fidelity scores over time.

CONCLUSIONS

In addition to identifying the under-reporting of fidelity of implementation strategies in the health literature, we developed and tested a simple checklist to assess the reporting of fidelity of implementation strategies. More research is indicated to assess the definitions and scoring schema of this checklist. Careful reporting of details about fidelity of implementation strategies will make an important contribution to implementation science.

Coronary artery disease in women: From the yentl syndrome to contemporary treatment

In recent years attention has been raised to the fact of increased morbidity and mortality between women who suffer from coronary disease. The identification of the so called Yentl Syndrome has emerged the deeper investigation of the true incidence of coronary disease in women and its outcomes. In this review an effort has been undertaken to understand the interaction of coronary disease and female gender after the implementation of newer therapeutic interventional and pharmaceutics’ approaches of the modern era.

Guidelines for the prevention of stroke in women: a statement for healthcare professionals from the American Heart Association/American Stroke Association

PURPOSE

The aim of this statement is to summarize data on stroke risk factors that are unique to and more common in women than men and to expand on the data provided in prior stroke guidelines and cardiovascular prevention guidelines for women. This guideline focuses on the risk factors unique to women, such as reproductive factors, and those that are more common in women, including migraine with aura, obesity, metabolic syndrome, and atrial fibrillation.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statement Oversight Committee and the AHA's Manuscript Oversight Committee. The panel reviewed relevant articles on adults using computerized searches of the medical literature through May 15, 2013. The evidence is organized within the context of the AHA framework and is classified according to the joint AHA/American College of Cardiology and supplementary AHA Stroke Council methods of classifying the level of certainty and the class and level of evidence. The document underwent extensive AHA internal peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

We provide current evidence, research gaps, and recommendations on risk of stroke related to preeclampsia, oral contraceptives, menopause, and hormone replacement, as well as those risk factors more common in women, such as obesity/metabolic syndrome, atrial fibrillation, and migraine with aura.

CONCLUSIONS

To more accurately reflect the risk of stroke in women across the lifespan, as well as the clear gaps in current risk scores, we believe a female-specific stroke risk score is warranted.

Reporting and representation of ethnic minorities in cardiovascular trials: a systematic review

BACKGROUND

Ethnic minority groups in the United States are at increased risk of developing cardiovascular diseases, experiencing adverse outcomes, and receiving suboptimal treatment. Such discrepancies may be related to a difference in race-specific outcomes in the management of cardiovascular diseases. However, little is known about the reporting and representation of ethnic minorities in major cardiovascular trials.

METHODS

A systematic review of major cardiovascular randomized controlled trials published in The Journal of the American Medical Association, The Lancet, and The New England Journal of Medicine between 1997 and 2010 was performed. We determined the reporting rate of the following ethnic minority groups in studies that enrolled American patients: whites, African Americans, Asians, and Hispanics.

RESULTS

A total of 250 randomized controlled trials that enrolled 1,103,694 patients were included in the systematic review. Among them, 56% (n = 140) of the trials reported information on race. No significant temporal changes in racial reporting were observed during the study period (P = .21). The median enrollment rate in trials for whites, African Americans, Hispanics, and Asians was 86%, 7%, 6%, and 4%, respectively. When compared with the population prevalence of disease burden, we found that whites were overrepresented (88% vs 78%, P < .001), whereas African Americans were underrepresented (3% vs 11%, P < .001), in trials of coronary artery disease.

CONCLUSIONS

Despite significant changes in the ethnic composition of the United States, we found that only about half of all major cardiovascular trials reported any racial information. Underrepresentation of ethnic minority groups in cardiovascular trials was observed.

Determinants of a subject's decision to participate in clinical anesthesia research

BACKGROUND

A top priority for research studies is to ensure that potential participants receive adequate information to make a truly informed decision. Understanding patient experiences with the recruitment process may identify areas for improvement in the consent process. We examined which factors were associated with the decision to consent in a clinical research study.

METHODS

Patients scheduled for elective surgery were asked to complete a questionnaire about the consent process, immediately after being approached to participate in an anesthesia-related research study. Sociodemographic characteristics, preoperative levels of anxiety and depression, medical comorbidities, factors that may affect decision to participate in a research study, and study design features were collected. A multivariable logistic regression model was estimated to identify factors associated with providing consent. Performance of the prediction model was assessed using the receiver operating characteristic curve. Internal validity was assessed by a bootstrap analysis.

RESULTS

In all, 282 participants completed the questionnaire. Of those, 179 (63%) had consented to participate in research, and 103 (37%) had declined to participate. In the multivariable logistic regression model, the odds of providing consent were higher for males (odds ratio [OR] [95% confidence interval]=2.49 [1.29-4.79]) and for patients with higher levels of patient comfort (OR=1.84 [1.22-2.78]). The odds of providing consent were lower for protocols that require additional testing (OR=0.15 [0.06-0.39]) and patients with higher levels of concern about blood sampling (OR=0.70 [0.54-0.90]) or worry about study risks (OR=0.72 [0.55-0.95]). Bootstrap analysis revealed a stable model with high internal validity.

CONCLUSIONS

The 2 strongest predictors of consent were male gender and comfort; predictors of refusal were protocol type that requires additional testing, greater concern about blood sampling and study risks, and lower overall patient comfort with the study. These patient and study characteristics may inform modification of the consent process for clinical research studies and facilitate the development of more accurate enrollment projections and strategies.

Considerations of sex and gender differences in preclinical and clinical trials

Women continue to be underrepresented in clinical trials, particularly in Phases I and II of experimental drug studies in spite of legislative guidelines in the USA, Canada, the European Union, Australia, and Japan requiring the inclusion of women in clinical trials. As such, women remain a vulnerable population subject to the adverse effects of pharmacological therapies. Thus, women experience higher rates of adverse drug reactions than do men and for women of reproductive age or who may be pregnant, therapeutic options may be limited. This chapter provides a brief history of inclusion of sex and gender as variables in clinical trials, summarizes governmental legislation for consideration of sex and gender in clinical trials and provides specific examples of drugs which have been withdrawn from the market because of side effects in women. Additional information related to sex and gender in preclinical testing, trial design, challenges to recruitment of women for clinical trials and statistical methods for analysis of data also is considered.