New research published in The Lancet has examined the gender-differential effects of the doses of angiotensin-converting-enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs) and β blockers when used for heart failure with reduced ejection fraction (HFrEF). Only patients with left ventricular ejection fraction less than 40% were included, and those who died within the first three months were excluded. The primary outcome was a composite of time to all-cause mortality or hospitalisation for heart failure: 1308 men and 402 women with were studied. The woman were on average older (74 [12] years vs 70 [12] years, p<0·0001) and had lower bodyweights (72 [16] kg vs 85 [18] kg, p<0·0001) and heights (162 [7] cm vs 174 [8] cm, p<0·0001), but BMI was not significantly different. A similar proportion of men and women reached guideline-recommended target doses of ACE inhibitors or ARBs (25% vs 23%) and β blockers (14% vs 13%). For men, the lowest hazards of death or hospitalisation for heart failure occurred at 100% of the recommended dose of ACE inhibitors or ARBs and β blockers, but women achieved about 30% lower risk at only 50% of the recommended doses, with no further decrease in risk at higher dose levels, with the sex differences persisting after adjusting for clinical covariates, including age and body surface area. Women with HFrEF may not need the same doses of ACE inhibitors or ARBs and β blockers as men. Read more here