Evaluation of drug therapy problems among outpatient hypertensive and type-2-diabetic patients at a Tertiary Hospital, South-West Nigeria

Abstract

Background: Health-related burden and poor outcomes due to drug therapy problems (DTPs) is a major concern in healthcare delivery especially in resource-poor countries.

Objective: To evaluate extent and types of DTPs as well as disease-specific clinical parameters in outpatient hypertensive and type-2-diabetic (T2D) patients attending a tertiary hospital in Nigeria.

Materials and Methods: This entailed questionnaire-guided interaction with 205-adult hypertensive and 198-T2D patients who were purposively enrolled, followed by a retrospective review of their medical records from September - November 2018. Domains of DTP explored included drug and dose selection, drug form, treatment duration, patients’ adherence and drug interactions. Data were summarised using descriptive statistics, while categorical variables were evaluated with Chi-square test at p<0.05 level of significance.

Results: Overall, 840 DTPs were identified among participants. This comprised 422(50.2 %) DTPs among T2D (average = 2.13 DTPs per patient), and 418(49.8 %) DTPs in the hypertensive (average = 2.04 DTPs per patient). The order of occurrence of DTPs among T2D was non-adherence [intentional, 173 (41.0 %) and unintentional, 69 (16.4 %)]>drug interactions, 155 (36.7 %)>drug selection, 25 (5.9 %); while for hypertensive patients, the order was non-adherence [intentional, 156 (37.3 %); unintentional, 57 (13.6 %)]>drug interactions, 157 (37.6 %)>dose selection, 25 (6.0 %)>drug selection, 23 (5.5 %). A total of 133(65.5 %) hypertensive patients had good blood pressure (≤140/90 mmHg) control, while the mean glycosilated haemoglobin was 7.5 (SD=2.6 %).

Conclusion: Extent of DTPs among participants is high, with non-adherence and drug interactions constituting the highest DTPs burden. There is generally a need for prescribers and pharmacists in particular to be wary of potential or actual DTPs during patient encounters, as this may ensure better therapeutic outcomes.

Keywords: Drug therapy problems, Hypertensive and type-2-diabetic patients, Outpatient, Nigeria