EMPA-REG HF Event Reduction Index: Explanation and Clinical Context
The EMPA-REG OUTCOME trial enrolled patients with type 2 diabetes mellitus and established atherosclerotic cardiovascular disease, randomized to Empagliflozin or placebo, and demonstrated a 35 % relative risk reduction in hospitalization for heart failure (HHF) with empagliflozin.
This calculator uses a user-entered estimate of baseline annual risk of HHF or cardiovascular death, applies the 35 % relative risk reduction observed in the trial, and projects the event risk over the chosen duration. The difference between the projected risk without treatment and with treatment is expressed as the “Event Reduction Index” (absolute percentage points reduction).
Clinical significance:
The tool helps clinicians and patients to visualise the magnitude of benefit that may accrue from empagliflozin over a defined period, translating relative risk reduction into absolute terms over time. It emphasises that even in populations with lower baseline risk, the proportional benefit remains similar, but the absolute benefit depends on baseline risk.
Interpretation:
If the baseline risk is low, the absolute reduction may be modest despite a strong relative reduction. If baseline risk is high, the absolute benefit becomes more substantial. Use of this tool should complement clinical judgement considering individual patient factors (renal function, HF status, glycaemic control, etc).
Reference:
Zinman B, et al. Empagliflozin, cardiovascular outcomes, and mortality in type 2 diabetes. N Engl J Med. 2015;373:2117-2128. DOI:10.1056/NEJMoa1504720.