Safety, adherence and efficacy of PCSK9 inhibitors: a retrospective real-world study

Introduction PCSK9 inhibitors demonstrated their effectiveness in reducing low-density lipoprotein cholesterol (LDL-C) and cardiovascular events in landmark trials. It remains unclear whether the results can be translated to Asian populations. This study was designed to assess the real-world safety, adherence and efficacy of PCSK9 inhibitors. Methods A retrospective review for patients newly initiated on PCSK9 inhibitors between 1st June 2017 and 31st July 2021 was conducted in a tertiary cardiology centre. Patients aged ≥ 21 years with a minimum one-month follow-up were included. Adverse drug reactions (ADRs), drug discontinuation, adherence patterns and efficacy between evolocumab and alirocumab groups were compared. Multivariable and propensity score adjusted Cox regression analyses were applied to analyse the outcomes. Results Of 87 patients screened, 80 (51 evolocumab; 29 alirocumab) were included. There were no significant differences between evolocumab and alirocumab groups in ADRs (11.8% vs 3.4%, adjusted HR, 2.97; 95% CI, 0.34 – 25.89 in multivariable analysis; adjusted HR, 3.24; 95% CI, 0.38–27.69 after propensity score adjustment) and discontinuation rates (27.5% vs 34.5%, adjusted HR, 0.89; 95% CI, 0.40–2.02 in multivariable analysis; adjusted HR, 0.88; 95% CI, 0.39–1.99 after propensity score adjustment). High medication cost was the main reason for discontinuation. One-third of patients had inadequate adherence to PCSK9 inhibitors. Both groups showed significant reductions of LDL-C compared to baseline. Conclusions PCSK9 inhibitors are efficacious, safe and well tolerated. Further studies are warranted to examine the cost-effectiveness of PCSK9 inhibitors to rationalise their sustainable use for cardiovascular prevention.