Paracetamol and adverse cardiovascular outcomes in patients with heart failure

Abstract Background Paracetamol is the most widely used pain killer worldwide, yet its potential influence on cardiovascular events among patients with heart failure (HF) remains unclear. Thus, this study aims to investigate both the short-term and long-term effects of paracetamol use on all-cause mortality and cardiovascular events in HF patients. Methods Using the previously validated territory-wide clinical information registry, paracetamol use was identified among all eligible patients with HF (N = 211,409) from 2000 to 2020. A case-crossover design was used to investigate the associations between short-term use of paracetamols and all-cause mortality and cardiovascular outcomes. Defined daily dose (DDD) was used to evaluate the dose-response relationship. Additionally, the marginal structural design was applied to model paracetamol use as a time-varying exposure and evaluate its long-term effects during the follow-up period. Results Of all eligible subjects, the mean age was 73.2±12.3 years, and 43.6% was male. Over a median follow-up of 10.5 years (interquartile range: 5.7-15.8), 113,258 (53.6%) patients were re-hospitalised for HF, HF-related death occurred in 11,892 (5.6%) patients, incident myocardial infarction (MI) in 28223 (13.3%) patients, incident stroke in 26458 (12.5%) patients, cardiovascular death (CVD) in 72,175 (34.1%) patients and all-cause death in 123,505 (58.4%) patients. Associating HF rehospitalisation to previous paracetamol exposure using the case-crossover design displayed an elevated risk (OR 3.62, 95% CI 3.53-3.71). Associations were similar for MI (OR 5.77, 95% CI 5.50-6.05), stroke (OR 2.37, 95% CI 2.25-2.49), HF-related death (OR 1.86, 95% CI 1.75-1.98), CVD (OR 3.64, 95% CI 3.55-3.73), and all-cause mortality (OR 3.32, 95% CI 3.26-3.39). Moreover, compared with paracetamol users taking the reference dose, users of low, medium and high doses of paracetamol had 16%, 17% and 52% higher risk of HF rehospitalisation. During the long-term follow-up, the average weighted hazard ratio (HR) for HF rehospitalisation in paracetamol users was 2.48 (95% CI 2.46–2.50) as compared with paracetamol non-users after accounting for all-cause mortality as a competing risk. Similarly, the average weighted HR for incident MI or stroke was 2.71 (2.62-2.81) and 3.45 (3.34-3.57), respectively. However, neutral results were shown for HF-related death, CVD and all-cause mortality. Conclusion The use of paracetamol among patients with HF is common. Paracetamol was associated with adverse cardiovascular outcomes both in short-term and long-term follow-up with a dose-response relationship, while its impact on long-term mortality remained neutral. Future randomized controlled trials or experimental studies are warranted to gain a comprehensive understanding of the underlying mechanisms driving such associations between paracetamol and adverse cardiovascular outcomes.