Patients with heart failure (HF) and a diminished ejection fraction have been the focus of research by the Heart Failure Collaboratory (HFC), which has resulted in the creation of a score that considers both the types and quantities of medications recommended by clinical guidelines. This score has the potential to be used to determine whether or not further advantages are seen from new treatments, even for patients who are already undergoing intensive medical treatment based on established guidelines. The authors investigated the efficacy of dapagliflozin according to a modified HFC score in the DAPA-HF (Dapagliflozin And Prevention of Adverse outcomes in Heart Failure) trial. Patients with heart failure and a decreased ejection fraction were randomly assigned to receive either dapagliflozin or a placebo in DAPA-HF. The modified HFC score accounted for race and electrocardiogram rhythm and rate, with a maximum possible score of 100%. The progression of HF or death from cardiovascular causes was the primary endpoint. The median modified HFC score was 50% (IQR: 27.5%-62.5%; range 0%-100%). The greatest tertile of the treatment score was related to a reduced risk of worsening HF or cardiovascular death compared with the lowest tertile (tertile 1, reference; tertile 2, HR: 0.97 [95% CI: 0.82-1.14]; tertile 3, HR: 0.83 [95% CI: 0.70-0.99]). The risk of worsening HF or cardiovascular death was reduced by dapagliflozin across all treatment score tertiles (hazard ratios [HRs] for dapagliflozin vs placebo across tertile 1 to 3 were: 0.76 [95% CI: 0.61-0.94], 0.76 [95% CI: 0.60-0.97], and 0.71 [95% CI: 0.55-0.90], respectively; P<sub style=”vertical-align: sub;”>interaction</sub> = 0.89]. Hospitalization rates for HF decreased, cardiovascular deaths decreased, overall mortality rates decreased, and the Kansas City Cardiomyopathy Questionnaire total symptom score (KCCQ-TTS) improved consistently. Without exception, dapagliflozin outperformed placebo across the board, independent of the adjusted HFC score. In clinical studies, this score can be simply generated and used to measure the additive effects of novel medicines.