Analysis of Adherence to anti-PCSK9 Antibody Therapy among Patients from Italy.

Introduction: Hypercholesterolemia is one of the main risk factors associated with atherosclerotic cardiovascular disease and coronary heart disease. Statins are the standard cholesterollowering treatment; however, they have shown, in clinical practice, a reduced adherence to therapy (<50%) and a modest achievement of the expected outcomes for treatment. This condition prompt scientific research to develop drugs with different mechanisms of action. In this regard, excellent results have been achieved with therapeutic use of monoclonal antibodies against PCSK9, enzyme involved in recycling of Low density lipoprotein receptors (LDLR) on the hepatocytes surface. Indeed, the reduction in receptor density caused by PCSK9 is associated with increased serum LDL levels.

Materials and methods: After the data extraction of all Local Health Authority (ASL) of Foggia patients (302) who received, in 2021, at least one administration of Alirocumab or Evolocumab, the therapeutic adherence was calculated, for each individual patient, by indirect method (calculation of the Medication Possession Ratio - MPR). According to scientific literature, patients were classified into: adherents (MPR>80%), average adherents (MPR between 40% and 80%) and non-adherents (MPR<40%). Patients were then stratified by gender and age groups (0-18, 19-49, 50-64, >65).

Results: The results show that, for both drugs (Alirocumab and Evolocumab), women are more adherent than men and the group of young adults (19-49 years old) is the one with the lowest adherence to therapy, 69% for Alirocumab and 56% for Evolocumab.

Conclusion: According to Italian Drug Agency (AIFA), poor therapeutic adherence is the main cause of ineffectiveness of drug therapies, and it is associated with increased hospitalizations, morbidity and mortality. Data obtained from this study allow to detect the categories of patients who need specific programs about the correct use of drugs, in order to increase therapeutic adherence and facilitate the achievement of the expected outcomes for treatment.