A retrospective nationwide analysis of evolocumab use in Sweden and its effect on low-density lipoprotein cholesterol levels

Abstract

Background: Treatment with proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors reduces low-density lipoprotein cholesterol (LDL-C) levels and decreases the incidence of major ischaemic events in clinical trials. However, less is known about the efficacy of PCSK9 inhibition in clinical practice. This study aimed to describe the change in LDL-C levels over time and LDL-C goal achievement in patients with/without atherosclerotic cardiovascular disease (ASCVD), who were prescribed evolocumab in clinical practice, and to describe adherence to and persistence with treatment.

Methods: Patients in Sweden with at least one evolocumab prescription filled between July 2015 and May 2020 were included. Medical history and lipid-lowering therapy (LLT) were sourced from national registries. LDL-C levels before and after treatment initiation were assessed using medical records. Persistence with and adherence to evolocumab and oral LLT were assessed up to 12 months after treatment initiation using the refill-gap method and proportion of days covered, respectively.

Results: Of the 2,360 patients with at least one prescription for evolocumab, 2,341 were included; 1,858 had ASCVD. Persistence with (76%) and adherence to (86%) evolocumab were high throughout the 12 months following initiation. Mean LDL-C levels decreased by 53% (95% confidence interval [CI]: 51-55%) in patients adherent to evolocumab (n = 567) and 59% (95% CI: 55-63%) in patients adherent to evolocumab and oral LLT (n = 186). Similar reductions in LDL-C were observed in patients with/without ASCVD. Reduced LDL-C levels remained stable during follow-up. Amongst patients adherent to evolocumab and those adherent to evolocumab and oral LLT, 23 and 55% achieved the LDL-C goal of <1.4 mmol/L, respectively.

Conclusions: The evolocumab LDL-C-lowering effect observed in clinical trials was confirmed in clinical practice in Sweden, particularly in patients also treated with oral LLT. During follow-up, adherence to and persistence with evolocumab were high, with stable reduced levels of LDL-C during observation.

Keywords: Adherence; LDL-C; PCSK9 inhibitors; evolocumab; persistence; real-world evidence.