The mortality risk of deferring optimal medical therapy in heart failure: a systematic comparison against norms for surgical consent and patient information leaflets
Aims: The prescription of optimal medical therapy for heart failure is often delayed despite compelling evidence of a reduction in mortality. We calculated the absolute risk resulting from delayed prescription of therapy. For comparison, we established the threshold applied by clinicians when discussing the risk for death associated with an intervention, and the threshold used in official patient information leaflets.
Methods and results: We undertook a meta-analysis of randomized controlled trials to calculate the excess mortality caused by deferral of medical therapy for 1 year. Risk ratios for angiotensin-converting enzyme inhibitors, beta-blockers and aldosterone antagonists were 0.80, 0.73 and 0.77, respectively. In patients who might achieve a 1-year survival rate of 90% if treated, a 1-year deferral of treatment reduced survival to 78% (i.e. an annual absolute increase in mortality of 12 in 100 patients). This corresponds to an additional absolute mortality risk per month of 1%. A survey of clinicians carried out to establish the risk threshold at which they would obtain written consent showed the majority (85%) sought written consent for interventions associated with a 12-fold lower mortality risk: one in 100 patients. A systematic review of UK patient information leaflets to establish the magnitude of risk considered sufficient to be stated explicitly showed that leaflets begin to mention death at a ∼18 000-fold lower mortality risk of just 0.0007 in 100 patients.
Conclusions: Deferring heart failure treatment for 1 year carries far greater risk than the level at which most doctors seek written consent, and 18 000 times more risk than the level at which patient information leaflets begin to mention death.