Changes in loop diuretic use following mitral valve surgery for mitral regurgitation according to age: a nationwide cohort study

Abstract Background Loop diuretic use may provide complementary information on postoperative heart failure burden after mitral valve surgery. Aims We investigated changes in loop diuretic use before and after mitral valve surgery for mitral regurgitation and assessed postoperative heart failure admission according to age. Methods and results Using Danish nationwide registries, we identified patients aged ≥18 years discharged after first-time mitral valve surgery for mitral regurgitation between 1996 and 2022. Loop diuretic use was assessed from redeemed prescriptions before surgery and at postoperative landmarks. Heart failure admission within 5 years was estimated with death as a competing risk. Among 6,840 patients, loop diuretic use was 46.2% before surgery and declined among survivors to 27.0% at 12–15 months and 23.7% at 36–39 months. Preoperative use was more frequent with increasing age, ranging from 27.9% in patients aged 18–49 years to 64.3% in those aged ≥80 years. Postoperatively, loop diuretic use remained common, ranging from 13.5% to 41.6% at 12–15 months and from 11.9% to 35.4% at 36–39 months across age groups. The 5-year cumulative incidence of heart failure admission was 20.9% (95% CI: 20.0–22.0%) overall and increased across age groups, from 13.9% to 27.4%. Preoperative loop diuretic use was associated with higher 5-year mortality irrespective of recorded heart failure status. Conclusions Loop diuretic use declined after mitral valve surgery for mitral regurgitation but remained common, particularly among older patients, and showed an age-related pattern consistent with hospital admission for heart failure.