Barriers to prescribing proprotein convertase subtilisin-kexin type 9 inhibitors after coronary revascularisation

Intern Med J. 2023 Jun;53(6):994-1001. doi: 10.1111/imj.15700. Epub 2022 Sep 4.

Abstract

Background: Guidelines advocate for intensive lipid-lowering in patients with atherosclerotic cardiovascular disease (ASCVD). In May 2020, evolocumab, a proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitor, became government subsidised in Australia for patients with ASCVD requiring further low-density lipoprotein cholesterol (LDL-C) lowering.

Aim: To identify barriers to prescribing PCSK9 inhibitors in hospitalised patients with ASCVD.

Methods: A retrospective 3-month, single-site, observational analysis was conducted in consecutive patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery. Lipid-lowering therapy prescriptions, including PSCK9 inhibitors, were assessed using electronic medical records, compared against the Australian Pharmaceutical Benefits eligibility criteria, and barriers to PCSK9 inhibitor use identified.

Results: Of 331 patients, 244 (73.7%) underwent PCI and 87 (26.3%) underwent CABG surgery. A lipid profile during or within 8 weeks of admission was measured for 202 (82.8%) patients undergoing PCI and 59 (67.8%) undergoing CABG surgery. In patients taking high-intensity statins on admission (n = 109), LDL-C ≥1.4, ≥1.8 and >2.6mmol/L was seen in 64 (58.7%), 44 (40.4%) and 19 (17.4%) patients respectively. High-intensity statin prescribing at discharge was high (>80%); however, ezetimibe was initiated in zero patients with LDL-C ≥1.4 mmol/L. There was variable advice given by clinicians for LDL-C targets. No patients met the criteria for subsidised PSCK9 inhibitor therapy, largely due to lack of qualifying lipid levels following combined statin and ezetimibe therapy.

Conclusion: Prescribing of non-statin LDL-C-lowering therapies remains low in patients with ASCVD. Underprescribing of ezetimibe and suboptimal lipid testing rates are barriers to accessing subsidised PCSK9i therapy using current Australian eligibility criteria.

Keywords: PCSK9 inhibitor; cardiovascular disease; coronary artery bypass graft; dyslipidaemia; low-density lipoprotein cholesterol; statin.

MeSH terms

  • Anticholesteremic Agents* / pharmacology
  • Australia / epidemiology
  • Cholesterol, LDL
  • Ezetimibe / therapeutic use
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors* / therapeutic use
  • Percutaneous Coronary Intervention*
  • Proprotein Convertase 9
  • Retrospective Studies
  • Subtilisins

Substances

  • Anticholesteremic Agents
  • PCSK9 protein, human
  • Proprotein Convertase 9
  • Cholesterol, LDL
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Ezetimibe
  • Subtilisins