OBJECTIVES: Medication nonadherence is common due to several reasons. It has been estimated that >10% of all first prescriptions for a new medication are never filled. Physicians' prescribing behavior may depend on the sector they operate due the sector specific incentives on payment systems. The objective of this study is to compare non-dispensed prescriptions prescribed in public and private health care settings using three different medicines, and study demographics of the people whose prescriptions were not dispensed.

METHODS: In this comparative register study, we evaluate three different types of medicines in 2017-2019. One is regularly taken (sitagliptin), the second is usually taken as needed (ibuprofen), and the third is potentially addictive medicine (pregabalin). All three cases were studied separately.

The data were collected from the national Prescription Centre, which includes all prescriptions prescribed for outpatient setting. We identified the prescriptions that had not been dispensed within the two-year prescription validity period.

Logistic regression was used to study factors that affect prescriptions to be non-dispensed. Prescriptions prescribed in the public and private sector were studied separately.

RESULTS: In total, 10.6% (public) and 11.9% (private) of sitagliptin prescriptions, 14.1% (public) and 13.4% (private) of ibuprofen prescriptions, and 14.7% (public) and 15.6% (private) of pregabalin prescriptions were never filled. In private sector age and sex affected to the probability to dispense the prescription. In addition to age and sex, in the public sector the prescribing month had a significant effect on the probability to dispense the prescription in all three cases.

CONCLUSIONS: The factors that affect the probability to dispense the prescription vary between the public and private sectors. In addition to patient demographics, reasons not to dispense a prescription can be related to other reasons such as a physician-patient relationship and financial burden thus socio-economic factors should be taken into account in future studies.