Low rate of sex-specific result reporting in cardiovascular trials

Women are Underrepresented in Non-small Cell Lung Cancer Clinical Trials: A Systematic Review

PURPOSE

To perform a systematic review of clinical trials examining non-small cell lung cancer (NSCLC) to better understand the equity afforded to women in the study of lung cancer.

METHODS

An electronic search was conducted for all NSCLC clinical trials published between 2010 and 2020 with included words "carcinoma, non-small cell, lung" and "non-small cell lung cancer." Studies from PubMed, Cochrane, and SCOPUS were included and were uploaded into Covidence to assist with systematic review. All articles were screened by two separate individuals and reviewed for location, study type, cancer stage, field of study of the research team, and percentage of females included. Student's t-test was used to compare the means of males and females.

RESULTS

Across the 269 studies that met inclusion criteria, fewer females than males were enrolled (38.7% vs. 61.1%; p < 0.0001). Compared with studies from 2010 to 2015, those from 2016 to 2020 had greater representation of females (36.7% vs. 41.4%, p = 0.0091, respectively). Both nonsurgical and surgical studies enrolled fewer female than male patients (38.1% vs. 61.7%, p < 0.0001; 43.1% vs. 57.2%, p = 0.0002, respectively). Clinical trials from the USA had the least difference between sexes with an average of 46.7% females enrolled. Less females compared with males were enrolled in early-stage NSCLC (37.6% female vs. 62.6% male, p < 0.0001) and late-stage NSCLC trials (37.6% female vs. 62.0% male, p < 0.0001).

CONCLUSIONS

Despite recent improvement, there continues to be significant underrepresentation of females compared with males in NSCLC clinical trials.

Sex-based differences in transfusion need after severe injury: Findings of the PROPPR study

BACKGROUND

Women are underrepresented in trauma research, and aggregated results of clinical trials may mask effects that differ by sex. It is unclear whether women respond differently to severe hemorrhage compared with men. We sought to evaluate sex-based differences in outcomes after severe trauma with hemorrhage.

METHODS

We performed a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Trauma patients predicted to require massive transfusion were randomized to a 1:1:1 vs 1:1:2 plasma to platelet to red blood cell transfusion ratio. Analysis was performed according to sex, controlling for clinical characteristics and transfusion arm.

RESULTS

A total of 134 women and 546 men were analyzed. In multivariable analysis, there was no difference in mortality at 24 hours (hazard ratio for women 0.64, 95% confidence interval 0.34-1.23, P = .18) or in time to hemostasis (hazard ratio 1.10, 95% confidence interval 0.84-1.42, P = .49) by sex. We observed no difference between sexes in volume of blood products transfused during active hemorrhage. However, after anatomic hemostasis, women received lower volumes of all products, with a 38% reduction in fresh frozen plasma (mean ratio 0.62 (95% confidence interval 0.43-0.89, P = .01), 49% reduction in platelets (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01) and 49% reduction in volume of red blood cells (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01).

CONCLUSION

Mortality and time to hemostasis of trauma patients with hemorrhage did not differ by sex. Although there was no difference in transfusion requirement during active hemorrhage, once hemostasis was achieved, women received fewer units of all blood products than men. Further research is required to determine whether women exhibit differences in coagulation during and after severe traumatic hemorrhage.

Determining If Sex Bias Exists in Human Surgical Clinical Research

Importance

Sex is a variable that is poorly controlled for in clinical research.

Objectives

To determine if sex bias exists in human surgical clinical research, to determine if data are reported and analyzed using sex as an independent variable, and to identify specialties in which the greatest and least sex biases exist.

Design, Setting, and Participants

For this bibliometric analysis, data were abstracted from 1303 original peer-reviewed articles published from January 1, 2011, through December 31, 2012, in 5 surgery journals.

Main Outcomes and Measures

Study type, location, number and sex of participants, degree of sex matching of included participants, and inclusion of sex-based reporting, statistical analysis, and discussion of data.

Results

Of 2347 articles reviewed, 1668 (71.1%) included human participants. After excluding 365 articles, 1303 remained: 17 (1.3%) included males only, 41 (3.1%) included females only, 1020 (78.3%) included males and females, and 225 (17.3%) did not document the sex of the participants. Although female participants represent more than 50% (n = 57 688 606) of the total number (115 377 213) included, considerable variability existed with the number of male (46 111 818), female (58 805 665), and unspecified (10 459 730) participants included among the journals, between US domestic and international studies, and between single vs multicenter studies. For articles included in the study, 38.1% (497 of 1303) reported these data by sex, 33.2% (432 of 1303) analyzed these data by sex, and 22.9% (299 of 1303) included a discussion of sex-based results. Sex matching of the included participants in the research overall was poor, with 45.2% (589 of 1303) of the studies matching the inclusion of both sexes by 50%. During analysis of the different surgical specialties, a wide variation in sex-based inclusion, matching, and data reporting existed, with colorectal surgery having the best matching of male and female participants and cardiac surgery having the worst.

Conclusions and Relevance

Sex bias exists in human surgical clinical research. Few studies included men and women equally, less than one-third performed data analysis by sex, and there was wide variation in inclusion and matching of the sexes among the specialties and the journals reviewed. Because clinical research is the foundation for evidence-based medicine, it is imperative that this disparity be addressed so that therapies benefit both sexes.

Reporting of Sex Effects by Systematic Reviews on Interventions for Depression, Diabetes, and Chronic Pain

Systematic reviews (SRs) have the potential to contribute uniquely to the evaluation of sex and gender differences (termed "sex effects"). This article describes the reporting of sex effects by SRs on interventions for depression, type 2 diabetes mellitus, and chronic pain conditions (chronic low back pain, knee osteoarthritis, and fibromyalgia). It includes SRs published since 1 October 2009 that evaluate medications, behavioral interventions, exercise, quality improvement, and some condition-specific treatments. The reporting of sex effects by primary randomized, controlled trials is also examined. Of 313 eligible SRs (86 for depression, 159 for type 2 diabetes mellitus, and 68 for chronic pain), few (n = 29) reported sex effects. Most SRs reporting sex effects used metaregression, whereas 9 SRs used subgroup analysis or individual-patient data meta-analysis. The proportion of SRs reporting the sex distribution of primary studies varied from a low of 31% (n = 8) for low back pain to a high of 68% (n = 23) for fibromyalgia. Primary randomized, controlled trials also infrequently reported sex effects, and most lacked an adequate sample size to examine them. Therefore, all SRs should report the proportion of women enrolled in primary studies and evaluate sex effects using appropriate methods whenever power is adequate.

Gender difference in the response to valsartan/amlodipine single-pill combination in essential hypertension (China Status II): An observational study

BACKGROUND

The China STATUS II is a prospective, multicentre, open-label, post-marketing, observational study including Chinese adults (aged ⩾ 18 years) with essential hypertension who were prescribed once-daily valsartan/amlodipine (Val/Aml 80/5 mg) single-pill combination. In order to examine gender differences in treatment response to Val/Aml, we further analysed data from the China STATUS II study.

METHODS

A total of 11,312 patients (6456 (57%) men and 4856 (43%) women) received the Val/Aml treatment for 8 weeks. After the treatment, we compared the proportion of patients not achieving the target systolic blood pressure (SBP: < 140 mm Hg) or diastolic blood pressure (DBP: < 90 mm Hg) in different age groups (by Fisher exact probability test) and estimated the changes in blood pressure (BP) according to age and gender, using a mixed model.

RESULTS

At enrolment, mean SBP was higher in the female versus the male patients (160.0 ± 12.71 versus 159.3 ± 12.31 mm Hg; p = 0.003), whereas the mean DBP was higher in the male versus the female patients (96.4 ± 10.65 versus 94.5 ± 10.72 mm Hg; p < 0.001). The overall proportion of women not achieving the target BP was less than that of men (57.41% versus 59.59%; p < 0.05) at 4 weeks and (22.22% versus 23.78%; p < 0.05) at 8 weeks after the Val/Aml treatment. Among both men and women, the proportion of patients not achieving the target SBP increased with age; however, the proportion not achieving the target DBP decreased with age. The mixed-model analysis showed that the changes in SBP were closely related to gender, indicating that the SBP-lowering effect after Val/Aml treatment might be better in women. In addition, the changes in DBP were closely related to age.

CONCLUSIONS

Gender might be a factor for consideration in the decision-making process of individualised antihypertensive therapy, in the future.

Sex-specific analysis of data in high-impact orthopaedic journals: how are we doing?

BACKGROUND

In 2001, the Institute of Medicine released a report stating that sex must be considered in all aspects and at all levels of biomedical research. Knowledge of differences between males and females in responses to treatment serves to improve our ability to care for our patients.

QUESTIONS/PURPOSES

The purpose of our study was to determine (1) if there is an increase in the proportion of sex-specific reporting from 2000 to 2005 and to 2010; and (2) whether there is a proportional difference in such reporting based on journal type: subspecialty versus general orthopaedics. We hypothesize that assessment of the role of sex in outcomes has improved during the past 15 years and that the proportion of studies with of sex-specific analyses has increased with awareness of the role of sex in clinical outcomes and disease states. We additionally hypothesized that the reporting of sex would be similar between subspecialty and general orthopaedic journals.

METHODS

Five high-impact orthopaedic journals, consisting of two general and three subspecialty journals, were chosen for review. Issues from even-numbered months during three calendar years (2000, 2005, 2010) were critically assessed for the presence of sex-specific analyses and reporting by two separate reviewers. Retrospective and prospective clinical studies, with a minimum of 20 patients, were included for analysis. Cadaveric, biomechanical, and in vitro studies were excluded. Review articles and clinical studies with less than 20 patients were excluded. A total of 821 studies that met inclusion criteria were analyzed: 206 in 2000, 277 in 2005, and 338 in 2010.

RESULTS

Overall, the proportion of sex-specific analyses increased during the three times studied (19%, 40/206, [95% CI, 0.14-0.25] of the studies in 2000; 27%, 77/277, [95% CI, 0.23-0.33] in 2005; and 30%, 102/338, [95% CI, 0.25-0.35] in 2010). The increase in the proportion of sex-specific analysis was significant between 2000 and 2005 (p = 0.033), but was not significant between 2005 and 2010 (p = 0.518). During each of the three specific years studied, general and subspecialty journals increased in the proportions that reported sex-based analyses, but specialty journals had significantly higher reporting rates only in 2000 (2000: 11.9%, 13/109, [95% CI, 0.06-0.18] and 27.8%, 27/97, [95% CI, 0.19-0.37], p = 0.004; 2005: 22.9%, 33/144, [95% CI, 0.16-0.30], and 33.1%, 44/133, [95% CI, 0.25-0.41], p = 0.059; 2010: 28.2%, 51/181, [95% CI, 0.22-0.35] and 32.5%, 51/157, [95% CI, 0.25-0.40], p = 0.390).

CONCLUSIONS

Our findings indicate that inclusion of sex-specific analysis and reporting in the orthopaedic literature improved during our study period, but are present in less than 1/3 of the studies. Although subgroup analysis and reporting are required by NIH guidelines, it is important that such analyses be published in non-NIH-funded studies to generate hypotheses regarding sex differences for subsequent research. These data also are important as they can be used in systematic reviews where large independent studies may not be available in the literature.

CLINICAL RELEVANCE

Where evaluating conditions that affect males and females, studies should be designed with sufficient sample size to allow for subgroup analysis by sex to be performed, and they should include sex-specific differences among the a priori research questions.

Does a change in health research funding policy related to the integration of sex and gender have an impact?

We analyzed the impact of a requirement introduced in December 2010 that all applicants to the Canadian Institutes of Health Research indicate whether their research designs accounted for sex or gender. We aimed to inform research policy by understanding the extent to which applicants across health research disciplines accounted for sex and gender. We conducted a descriptive statistical analysis to identify trends in application data from three research funding competitions (December 2010, June 2011, and December 2011) (N = 1459). We also conducted a qualitative thematic analysis of applicants' responses. Here we show that the proportion of applicants responding affirmatively to the questions on sex and gender increased over time (48% in December 2011, compared to 26% in December 2010). Biomedical researchers were least likely to report accounting for sex and gender. Analysis by discipline-specific peer review panel showed variation in the likelihood that a given panel will fund grants with a stated focus on sex or gender. These findings suggest that mandatory questions are one way of encouraging the uptake of sex and gender in health research, yet there remain persistent disparities across disciplines. These disparities represent opportunities for policy intervention by health research funders.

Sex and gender differences in myocarditis and dilated cardiomyopathy

Heart failure due to nonischemic dilated cardiomyopathy (DCM) contributes significantly to the global burden of cardiovascular disease. Myocarditis is, in turn, a major cause of acute DCM in both men and women. However, recent clinical and experimental evidence suggests that the pathogenesis and prognosis of DCM differ between the sexes. This seminar provides a contemporary perspective on the immune mediators of myocarditis, including interdependent elements of the innate and adaptive immune response. The heart's acute response to injury is influenced by sex hormones that appear to determine the subsequent risk of chronic DCM. Preliminary data suggest additional genetic variations may account for some of the differences in epidemiology, left ventricular recovery, and survival between men and women. We highlight the gaps in our knowledge regarding the management of women with acute DCM and discuss emerging therapies, including bromocriptine for the treatment of peripartum cardiomyopathy.

Inclusion of women and gender-specific analyses in randomized clinical trials of treatments for depression

BACKGROUND

The higher prevalence and cost of depression for women compared with men and the possible gender differences in treatment response demand the inclusion of women in clinical trials of depression treatments. The 1993 National Institutes of Health (NIH) Revitalization Act set a new standard, requiring investigators to consider the inclusion of women and analyze outcomes by gender, yet compliance with these standards in depression research has not been examined systematically. The purpose of this study is to examine the inclusion of women and gender-specific analyses in recent randomized clinical trials (RCTs) for depression.

METHODS

RCTs were identified through a MEDLINE search for trials published between January 1 and December 31, 2007, and a Clinicaltrials.gov search of self-identified interventional studies to treat depression.

RESULTS

Of the 150 RCTs for depression published in 2007, 15% did not report the gender composition of their sample, 50% of studies did not analyze outcomes by gender, and 12% controlled for gender but did not analyze for gender differences. Of the 768 trials reviewed on Clinicaltrials.gov, 89% reported recruiting male and female participants, yet <1% reported an intention to analyze results by gender.

CONCLUSIONS

Many recent studies of depression treatments include women but do not examine outcomes by gender. Understanding how women differ from men in response to treatment is critical for enhancing treatment efficacy for the greatest number of adults with depression.

Strategies and methods to study sex differences in cardiovascular structure and function: a guide for basic scientists

Background

Cardiovascular disease remains the primary cause of death worldwide. In the US, deaths due to cardiovascular disease for women exceed those of men. While cultural and psychosocial factors such as education, economic status, marital status and access to healthcare contribute to sex differences in adverse outcomes, physiological and molecular bases of differences between women and men that contribute to development of cardiovascular disease and response to therapy remain underexplored.

Methods

This article describes concepts, methods and procedures to assist in the design of animal and tissue/cell based studies of sex differences in cardiovascular structure, function and models of disease.

Results

To address knowledge gaps, study designs must incorporate appropriate experimental material including species/strain characteristics, sex and hormonal status. Determining whether a sex difference exists in a trait must take into account the reproductive status and history of the animal including those used for tissue (cell) harvest, such as the presence of gonadal steroids at the time of testing, during development or number of pregnancies. When selecting the type of experimental animal, additional consideration should be given to diet requirements (soy or plant based influencing consumption of phytoestrogen), lifespan, frequency of estrous cycle in females, and ability to investigate developmental or environmental components of disease modulation. Stress imposed by disruption of sleep/wake cycles, patterns of social interaction (or degree of social isolation), or handling may influence adrenal hormones that interact with pathways activated by the sex steroid hormones. Care must be given to selection of hormonal treatment and route of administration.

Conclusions

Accounting for sex in the design and interpretation of studies including pharmacological effects of drugs is essential to increase the foundation of basic knowledge upon which to build translational approaches to prevent, diagnose and treat cardiovascular diseases in humans.

Inclusion, analysis, and reporting of sex and race/ethnicity in clinical trials: have we made progress?

BACKGROUND

The National Institutes of Health (NIH) Revitalization Act of 1993 requires that NIH-funded clinical trials include women and minorities as participants; other federal agencies have adopted similar guidelines. The objective of this study is to determine the current level of compliance with these guidelines for the inclusion, analysis, and reporting of sex and race/ethnicity in federally funded randomized controlled trials (RCTs) and to compare the current level of compliance with that from 2004, which was reported previously.

METHODS

RCTs published in nine prominent medical journals in 2009 were identified by PubMed search. Studies where individuals were not the unit of analysis, those begun before 1994, and those not receiving federal funding were excluded. PubMed search located 512 published articles. After exclusion of ineligible articles, 86 (17%) remained for analysis.

RESULTS

Thirty studies were sex specific. The median enrollment of women in the 56 studies that included both men and women was 37%. Seventy-five percent of the studies did not report any outcomes by sex, including 9 studies reporting <20% women enrolled. Among all 86 studies, 21% did not report sample sizes by racial and ethnic groups, and 64% did not provide any analysis by racial or ethnic groups. Only 3 studies indicated that the generalizability of their results may be limited by lack of diversity among those studied. There were no statistically significant changes in inclusion or reporting of sex or race/ethnicity when compared with 2004.

CONCLUSIONS

Ensuring enhanced inclusion, analysis, and reporting of sex and race/ethnicity entails the efforts of NIH, journal editors, and the researchers themselves.

Statins for the primary prevention of cardiovascular events in women with elevated high-sensitivity C-reactive protein or dyslipidemia: results from the Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) and meta-analysis of women from primary prevention trials

BACKGROUND

Statin therapy in women without cardiovascular disease (CVD) is controversial, given the insufficient evidence of benefit. We analyzed sex-specific outcomes in the Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) and synthesized the results with prior trials.

METHODS AND RESULTS

JUPITER participants included 6801 women > or =60 years of age and 11 001 men > or =50 years of age with high-sensitivity C-reactive protein > or =2 mg/L and low-density lipoprotein cholesterol <130 mg/dL randomized to rosuvastatin versus placebo. Meta-analysis studies were randomized placebo-controlled statin trials with predominantly or exclusively primary prevention in women and sex-specific outcomes (20 147 women; >276 CVD events; mean age, 63 to 69 years). Absolute CVD rates (per 100 person-years) in JUPITER women for rosuvastatin and placebo (0.57 and 1.04, respectively) were lower than for men (0.88 and 1.54, respectively), with similar relative risk reduction in women (hazard ratio, 0.54; 95% confidence interval, 0.37 to 0.80; P=0.002) and men (hazard ratio, 0.58; 95% confidence interval, 0.45 to 0.73; P<0.001). In women, there was significant reduction in revascularization/unstable angina and nonsignificant reductions in other components of the primary end point. Meta-analysis of 13 154 women (240 CVD events; 216 total deaths) from exclusively primary prevention trials found a significant reduction in primary CVD events with statins by a third (relative risk, 0.63; 95% confidence interval, 0.49 to 0.82; P<0.001; P for heterogeneity=0.56) with a smaller nonsignificant effect on total mortality (relative risk, 0.78; 95% confidence interval, 0.53 to 1.15; P=0.21; P for heterogeneity=0.20). Similar results were obtained for trials that were predominantly but not exclusively primary prevention.

CONCLUSIONS

JUPITER demonstrated that in primary prevention rosuvastatin reduced CVD events in women with a relative risk reduction similar to that in men, a finding supported by meta-analysis of primary prevention statin trials. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00239681.