OBJECTIVES: To investigate for trends in sex-related differences in the invasive diagnostic-therapeutic cascade in a population of patients with acute coronary syndromes (ACS).

DESIGN: A nationwide cohort study.

SETTING: Administrative and clinical registries covering all hospitalisations, invasive cardiac procedures and deaths in the Danish population of 5.6 million inhabitants.

PARTICIPANTS: We included 52,565 patients aged 30-90 years who were hospitalised with a first ACS from January 2005 to November 2011. Follow-up was 60 days from the day of index admission.

MAIN OUTCOME MEASURES: Diagnostic coronary angiography, percutaneous coronary intervention or coronary artery bypass within 60 days of index admission.

RESULTS: Women constituted 36%, were older, had more comorbidity and were less likely to be admitted to a hospital with cardiac catheterisation facilities than men. Mortality rates were similar for both sexes. Diagnostic coronary angiography was performed less frequently on women compared with men, both within 1 day (31% vs 42%; p<0.001) and within 60 days (67% vs 80%; p<0.001), yielding adjusted female-male HRs of 0.83 (0.79-0.87) and 0.86 (0.84-0.89), respectively.Among the 39,677 patients undergoing coronary angiography, non-obstructive coronary artery disease was more frequent among women than men (22% vs 9%; p<0.001). Women were less likely to undergo percutaneous coronary intervention (58% vs 72%; p<0.001) and coronary artery bypass (6% vs 11%, p<0.001) within 60 days than men, yielding adjusted HRs of 0.96 (0.92-0.99) and 0.81 (0.74-0.89), respectively. The sex-related differences were not attenuated over time for any of the invasive cardiac procedures (p values for trend >0.05).

CONCLUSIONS: In this nationwide study, men were more likely to undergo an invasive approach than women when hospitalised with a first ACS--a difference persisting from 2005 to 2011. Future studies should focus on the potential mechanisms behind this differential treatment.