Abstract Body (Do not enter title and authors here): Background: Although Heart failure (HF) has similar lifetime risk among both men and women, women are more likely to develop HF with preserved ejection fraction and experience distinct risk factors and outcomes. Despite this, women remain underrepresented in HF clinical trials, particularly in studies of HF with reduced ejection fraction and device-based interventions, with average women participation of 25%. As a result, current guideline recommendations, including those from the leading US cardiology institutes, are predominantly based on evidence derived from male cohorts, compromising the applicability of these recommendations to women. In our study, we examined the the representation of women in the studies used to formulate the current HF management practice guidelines.

Methods: We conducted systematic review of all primary studies cited in the 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure that reported the number of women participants and included in the evidence table; those were mainly used to derive the current recommendations. Studies were classified into randomized controlled trials (RCTs) and nonrandomized studies. The average women participation proportion were analyzed to RCTs and non-RCTs and comparison done for the average proportion of women participants by year of publication and the section where was cited in the guidelines.

Results: A total of 462 studies (192 RCTs, 270 non-RCTs) were included in the analysis, the mean proportion of women participants was 27.8% in RCTs and 36.2% in non-RCTs. Temporal analysis demonstrated a gradual increase in women representation in both study types; however, the gap between RCTs and non-RCTs persisted. In the most recent period, women representation reached 33.2% in non-RCTs and 26.4% in RCTs. Despite these improvements, women remain consistently underrepresented relative to their disease burden.

Conclusion: Women representation in HF studies cited in the current clinical practice guidelines remains suboptimal, particularly within RCTs. Although modest improvements have occurred over time, significant disparities persist. These findings underscore the need to identify the barriers and implement systematic strategies to enhance the inclusion of women in clinical research, especially in studies that inform clinical practice guidelines, to ensure equitable, evidence-based care for all patients with HF.