Integrating sex and gender in studies of cardiac resynchronization therapy: a systematic review

AIMS: To examine the prevalence, temporal changes, and impact of the National Institute of Health (NIH) Sex as a Biological Variable (SABV) policy on sex and gender reporting and analysis in cardiac resynchronization therapy (CRT) cohort studies. METHODS AND RESULTS: We searched MEDLINE, EMBASE, and Web of Science for cohort studies reporting the effectiveness and safety of CRT in heart failure patients from January 2000 to June 2020, with no language restrictions. Segmented regression analysis was used for policy analysis. We included 253 studies. Fourteen per cent considered sex in the study design. Outcome data disaggregated by sex were only reported in 17% of the studies. Of the studies with statistical models (n = 173), 57% were adjusted for sex. Sixty‐eight per cent of those reported an effect size for sex on the outcome. Sex‐stratified analyses were conducted in 13% of the studies. Temporal analysis shows an increase in sex reporting in background, statistical models, study design, and discussion. Besides statistical models, NIH SABV policy analysis showed no significant change in the reporting of sex in study sections. Gender was not reported or analysed in any study. CONCLUSIONS: There is a need to improve the study design, analysis, and completeness of reporting of sex in CRT cohort studies. Inadequate sex integration in study design and analysis may potentially hinder progress in understanding sex disparities in CRT. Deficiencies in the integration of sex in studies could be overcome by implementing guidance that already exists.