Impact of polypharmacy on 3-year mortality in patients with heart failure: a retrospective study

Abstract Background Guideline-directed medical therapy (GDMT) is important in heart failure management; however, polypharmacy itself may impact heart failure. Although measures against polypharmacy are needed, current discussion on unilateral drug tapering (including the drugs that should be tapered) is insufficient. In this study, we investigated the relationship between the number of prescribed GDMT drugs and prognosis in patients with heart failure. Methods In this single-centre retrospective study, 3,146 eligible patients with heart failure were included and divided into four groups based on the median number of prescribed GDMT drugs and the median number of drugs not included in the GDMT (ni-GDMT) at the time of hospital discharge. The definition of GDMT was based on various Japanese guidelines. The primary outcome was all-cause mortality within 3 years of hospital discharge. Results A total of 252 deaths were observed during the 3-year follow-up period. Kaplan–Meier analysis revealed that groups with GDMT drug count ≥ 5 and ni-GDMT drug count < 4 had the lowest mortality, and those with GDMT drug count < 5 and ni-GDMT drug count ≥ 4 had the highest mortality (log-rank, P < 0.001). Cox regression analysis revealed a significant association between ni-GDMT drug count and all-cause mortality, even after adjustment for number of GDMT medications, age, male, left ventricular ejection function < 40%, hemoglobin, albumin levels, and estimated glomerular filtration rate HR = 1.06 (95% CI: 1.01–1.11), P = 0.020. Conversely, the GDMT drug count was not associated with increased mortality rates. Conclusions The ni-GDMT drug count was significantly associated with 3-year mortality in patients with heart failure. Conversely, the GDMT drug count did not worsen the prognosis. Polypharmacy measures should consider ni-GDMT drug quantity to improve the prognosis and outcomes in patients with heart failure.