Heart failure calculator predicts drug effects

A prescription can stall before the first pill is taken. In heart failure, clinicians often hesitate over the possibility of low blood pressure, worsening kidney function or high potassium levels; a new free calculator now estimates those effects for different treatment combinations, using individual data from 38,753 participants in nine major trials.

The tool was developed by The George Institute for Global Health with Brigham and Women's Hospital and Harvard Medical School. It takes in a patient's age, sex, body mass index, starting blood pressure, kidney function, potassium level and history of heart-failure hospitalization, then produces estimates for five major medicine classes: an angiotensin receptor blocker–neprilysin inhibitor (ARNI), an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (ACEI/ARB), a sodium-glucose cotransporter 2 inhibitor (SGLT2i), and steroidal or nonsteroidal mineralocorticoid receptor antagonists (sMRA and nsMRA).

The underlying trade-off is narrower than the fears that can block treatment. The recommended combinations were associated with modest blood-pressure reductions, early declines in kidney function and small to modest rises in serum potassium. Against standard care, however, the risk of worsening heart-failure events fell by 31% to 61%. Current guidelines recommend a four-pillar approach for heart failure with reduced ejection fraction— a beta-blocker, ARNI, sMRA and SGLT2i—shown to reduce all-cause mortality by up to 60%. Registry studies suggest that only 2% of eligible patients receive that full treatment approach.

The model was tested against observed outcomes from 1,016 participants in four additional trials, and its estimates aligned with what happened in those studies. That supports the calculator's reliability, but it does not settle how well it will work across everyday patients: the authors say the model was developed from clinical-trial populations and may not be fully generalizable.

So what changes in practice? A clinician can use a patient's own starting measurements to see the likely short-term effects of combining therapies, rather than relying only on broad averages or avoiding treatment because of uncertainty. That could make it easier to start medicines together when appropriate, while keeping monitoring and clinical judgment in the loop. The calculator is available free of charge, but the sources do not establish how widely it is being used or whether it improves prescribing outside trials.