(P-092) Primary Non-adherence in Primary Care in the Netherlands

Background: Not all patients collect a newly prescribed medicine from the pharmacy. This is called primary non-adherence (PNA).

Objectives: This study aims to estimate PNA in primary care in the Netherlands and to investigate patient characteristics possibly associated with PNA.

Methods: We included patients (>=60 years) from the Nivel (Netherlands Institute for Health Services Research) Primary Care Database who received a prescription from a general practitioner (GP) during 2012-2013. Each prescription from this database was linked on patient level with pharmacy dispensing information (Dutch Foundation for Pharmaceutical Statistics (SFK) database). PNA was defined as a new prescription by the GP (>1 year not prescribed or dispensed) with no record of dispensing in the SFK within the 365 days following the prescription. Characteristics (sex, age, neighborhood socioeconomic status, comedication and comorbidities) were evaluated for their association with PNA using mixed effects logistic regression models.

Results: This study included 4136 subjects and 23,150 new drug treatments. PNA was 2070/23,150 = 8.9%. For cardiovascular drugs (ATC class C) and drugs for the nervous system (class N) the PNA was lower than the overall percentage (4.0% and 7.9% respectively), but for class A (alimentary tract and metabolism) or B (blood and blood forming agents) these percentages were higher (10.4% and 12.1%, respectively). Only sex was found to be associated with PNA (OR for male vs female 1.19, 95% confidence interval 1.05-1.36).

Conclusions: The percentage of PNA was 8.9% but differed across ATC classes. Using a prescription database may therefore lead to overestimation of the actual drug exposure.