Prof Nelson Mandela University Port Elizabeth, Eastern Cape, South Africa
Background: Poor adherence to medication is a barrier to effective treatment in most diseases, especially in dementia where cognitive impairment reduces patients' awareness of non-adherence and their ability to manage their medication.
Objectives: To analyze a South African medical insurance scheme claims database to determine adherence to anti-dementia products.
Methods: A retrospective drug utilization study on a section of private healthcare data in South Africa for 2018 was conducted. All products in Anatomical Therapeutic Chemical (ATC) subgroup N06D (anti-dementia drugs) were extracted and analyzed. Medication Persistence and Medication Possession Ratio modified (MPRm) were calculated.
Results: A total of 42 patients were prescribed 211 products in ATC subgroup N06D during the year. The average age of the 42 patients was 67.00 (SD=19.14) years. Only memantine (N06DX01), donepezil (N06DA02) and ginkgo biloba (N06DX02, one prescription) were reimbursed. Persistence, defined as how long a patient has been taking the medication without taking into account any breaks in therapy, was on average 129 days for donepezil (n=15 patients) and on average 104 days for memantine (23 patients). Most patients were therefore receiving the products for only 3 to 4 months of the year. The MPRm was calculated using the total days supplied divided by Medication Persistence. The average MPRm was 0.93 for donepezil (n=15 patients), and 0.83 for memantine (n=23 patients). There was therefore not long delays between the filling of prescriptions, and adherence was acceptable ( >0.80) but treatment periods were relatively short. Combination therapy was not common, with only three patients receiving both memantine and donepezil during the year. One patient (a 57 year-old female) received a prescription for both memantine and donepezil every month, while the other two patients received on average 8 prescriptions for the two active ingredients each during the year.
Conclusions: Anti-dementia drugs constituted a small percentage of prescriptions in this healthcare setting, and most patients only received prescriptions for three or four months, without long breaks between refilling their prescriptions. Adherence was acceptable but the reason for the early discontinuation of anti-dementia medication deserves further investigation.
