Medication adherence and associated costs among patients with type 2 diabetes accessing care at a tertiary health care facility in Nigeria: A cross-sectional study

Abstract

Background: Diabetes mellitus (DM) affects a significant proportion of the Nigerian population with substantial health and economic burden. Adherence to medication is critical to achieving effective control of diabetes, as poor adherence causes suboptimal glycemic control and diabetic complications, increasing the disease health and economic burden. The study aimed to assess the current state of adherence to anti-diabetic medication and associated costs among a population of patients with T2DM attending medical outpatient’s clinic in a tertiary healthcare facility, south-east, Nigeria.

Method: A cross-sectional study was carried out using a structured questionnaire incorporating the 8- item Morisky medication adherence questions, to determine adherence and associated factors of non-adherence to anti-diabetic medications among a population of outpatients at the Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi. Demographic characteristics, clinical and medication adherence information were collected from participants. Patients’ records were reviewed to abstract information on drug use pattern and associated costs of medication. Data was analyzed with SPSS version 16 and GraphPad Prism version 5.03 software, summarized using descriptive statistics and multiple regression analysis.

Findings: A total of 208 patients diagnosed with T2DM were interviewed using questionnaires while 300 prescriptions of anti-diabetic medications were analyzed. Mean age of patients was 53.5 (±0.5) years. Approximately 53% of participants were adherent while up to 47.1% were non-adherent to anti-diabetic medications. Socio-demographic, clinical and medication characteristics of participants showed no association with medication adherence. Multiple medications and associated costs were the most common factors associated with non-adherence. Mean cost of prescription amounted to $13.30 per patient, at $0.53 per patient per day. Metformin was the most prescribed anti-diabetic medication, constituting up to 16% of the total cost of medication

Conclusion: There was a significant sub-optimal adherence to anti-diabetic medication among the diabetes patients. Multiple medication and associated costs contributed most to non-adherence suggesting scope for improved rational use of medicines to enhance patient’s adherence and improved outcome.