New tool predicts side effects that stall heart failure treatment

Clinical takeaway: The physiologic effects that make clinicians hesitate, such as hypotension, worsening kidney function, and hyperkalemia, are modest and quantifiable in advance, while the benefits of combination therapy remain significant. 

Heart failure therapy has a delivery complexity problem. Four-pillar medical therapy can cut all-cause mortality by as much as 60%, yet registry data suggest only about 2% of eligible patients receive the full regimen. The reasons clinicians most often cite for holding back are not doubts about efficacy but worries about adverse effects such as low blood pressure, reduced kidney function, or rising potassium. 

Clinicians knew the early physiologic shifts were real, but not how large to expect them in the patient in front of them. That uncertainty has fed a pattern of deferred starts that leaves patients unprotected for months. A new pooled analysis of individual patient data from landmark heart failure trials now puts data against those expected shifts, and pairs them with a freely available calculator that generates an estimate for each individual patient. 

Across recommended combinations, the model found that the feared physiologic effects are modest: single-digit drops in systolic blood pressure, early declines in estimated glomerular filtration rate under 10 mL/min/1.73 m², and potassium increases of roughly 0.2 to 0.35 mmol/L over the first two to 12 weeks of therapy. Effects ran somewhat larger in reduced ejection fraction than in mildly reduced or preserved ejection fraction. Those shifts sit against relative reductions in worsening heart failure events of 31% to 61% compared with standard care, depending on the combination. 

The calculator turns those pooled estimates into a patient-specific forecast. A clinician enters age, sex, body mass index, baseline blood pressure, kidney function, potassium, and heart failure hospitalization history, selects any combination of the five drug classes the tool covers, which do not include beta-blockers, and gets the expected short-term change in all three parameters before writing the prescription. Against data from 1,016 patients in four separate trials, the tool's estimates aligned with observed outcomes. 

The analysis pooled individual participant data from 38,753 patients in nine randomized trials spanning the full range of ejection fraction. Drug-class effects were modeled as additive after covariate adjustment, meaning estimates for untested combinations are extrapolated rather than observed. The authors note the trial populations may limit generalizability to broader practice. 

The free calculator is live now, requiring only input of routine clinic values that a PCP already should have on hand. It's not clear if more information will help to boost more aggressive prescribing, but authors are hopeful. 

"By providing a personalised estimate of what to expect when initiating combination therapy, the calculator can reduce uncertainty and give clinicians greater confidence to prescribe these treatments simultaneously, ultimately helping more patients receive therapies that improve long-term outcomes," said Nelson Wang, a cardiologist and senior research fellow at The George Institute for Global Health. 

Source: Wang N, et al. (2026 Aug 31) Nat Med. Short-term effects of combinations of heart failure therapies on blood pressure, kidney function and serum potassium