Quantitative Adherence Level Evaluation Among Long-Term Antiretroviral Therapy Patients in Latvia

Anna Gavrilova; Maksims Zolovs; Inga Urtāne; Dins Šmits

doi:10.2147/PPA.S437611

Quantitative Adherence Level Evaluation Among Long-Term Antiretroviral Therapy Patients in Latvia

Patient Prefer Adherence. 2023 Dec 5:17:3147-3154. doi: 10.2147/PPA.S437611. eCollection 2023.

Authors

Anna Gavrilova¹, Maksims Zolovs^{2

3}, Inga Urtāne¹, Dins Šmits⁴

Affiliations

¹ Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Rīga Stradiņš University, Riga, LV-1007, Latvia.
² Statistical Unit, Faculty of Medicine, Rīga Stradiņš University, Riga, LV-1048, Latvia.
³ Institute of Life Sciences and Technology, Daugavpils University, Daugavpils, LV-5401, Latvia.
⁴ Department of Public Health and Epidemiology, Faculty of Public Health and Social Welfare, Rīga Stradiņš University, Riga, LV-1007, Latvia.

Abstract

Introduction: The global prevalence of human immunodeficiency virus (HIV) remains substantial, particularly in regions with limited resources, despite the progress in scientific knowledge and the accessibility of antiretroviral therapy (ART). ART is the cornerstone of HIV treatment. Ensuring proper adherence to medication therapy is essential for effective HIV infection control. Meanwhile, Latvia reported one of the highest rates of HIV infections among EU countries.

Purpose: This study aimed to assess adherence levels to ART among long-term users by utilizing the National Health Service prescription electronic database records. It is essential to determine whether non-adherence is a problem at the state level.

Patients and methods: This retrospective study was conducted utilizing the Latvian National Health Service's reimbursed prescription database, covering the period from January 2017 to December 2018. The analysis included ART prescriptions. Medication adherence was assessed using a Proportion of Days Covered (PDC) calculation. The adherence rates were categorized into three groups: (1) < 80% (non-adherence), (2) 80% to 90% (suboptimal adherence), and (3) > 90% (optimal adherence) groups.

Results: A total of 25,892 ARV medicines prescription records for 1471 patients were analysed. The adherence level of long-term ART was 38.3%. Of all patients, only 37 (2.5%) had achieved an optimal and 25 (1.7%) suboptimal adherence level. Meanwhile, the remaining patients (95.8%) were identified as non-adherent to therapy. It has been determined that 96.1% (n=1414) of patients experienced a time gap of more than 90 days between their prescriptions at least once. On average, each patient had 3.5 of these gaps, with a maximum of 7 times.

Conclusion: Medication adherence level to ART is low in Latvia. Less than 3% of patients achieved optimal adherence levels with a PDC higher than 90%. These results are concerning. Further studies and interventions must be conducted to enhance adherence levels.

Keywords: AIDS; ART; HIV; National Health Service; PDC.