Methods And Materials
Study setting and population
The study was conducted in the Diabetes mellitus clinic at Mbarara Regional Referral Hospital (MRRH) located in Mbarara City, Mbarara district, south western region, Uganda from July to October 2020; it is a government owned referral and teaching hospital for Mbarara University Medical School with patient capacity of approximately of 350 beds. The general medical care in the hospital is free and the Diabetes mellitus clinic is one of the major ambulatory clinics operated once a week within the hospital. The study population was diabetes mellitus patients (both type 1 and type 2) who attended the Diabetes clinic at MRRH between July and October, 2020.
Study design
Descriptive cross-sectional study was done, Outcome variables were Non-adherence prevalence and Factors contributing to non-adherence to antidiabetic medication
Sampling procedure and sample size Estimation
The sample size was calculated using finite population formula and the prevalence of non-adherence to antidiabetic medication of 28.9% in Uganda by (13) was used for this calculation. Using formula (14);
Where:
Zα = Standard deviation at 95% confidence interval corresponding to 1.96
p = assumed population of diabetes mellitus patients who are non-adherent to treatment, results of a study at Mulago hospital (13) were used, so P = 28.9%
1-P = is the probability of diabetes mellitus patients who were adhering to their antidiabetic medication, therefore 1-P = 71.1%
e = level of precision (in proportion of one, therefore considering 5%, e = 0.05)
n = sample size estimation of patients with diabetes mellitus
Estimated sample size, 
Estimated size (N) = 316
Number of active patients at the Diabetes clinic (MRRH) was approximately 1,074 (source; Diabetes clinic records). The finite population correction factor (n)
Total number of active patients (no) = 1074 (adopted from Diabetes clinic records)
Estimated sample size (N) = 316
Therefore, sample size (n) = 245 patients
Adding 5% for incomplete information and withdraw from the study, 245 x 0.05 = 12
Total target sample = 245 + 12 = 257.
Systematic random sampling technique was used to select study participants.
Sampling interval = 1074 / 257 = 4, interviewed every fourth patient on the clinic appointment list starting from a number randomly selected from 1 to 4
Data collection procedure
Structured investigator-administered pre-tested questionnaire was used for each participant to collect information on socio-demographic and adherence characteristics. A check list was used to document diseases (Diabetes mellitus and other comorbidities) and drugs’ (antidiabetic medication) information for each patient.
A detailed history was acquired (English), translated where necessary for patients who do not understand English.
Non-adherence to antidiabetic medication was assessed based on the Hill-Bone Medication Adherence scale (15).
Data Quality control
A registered nurse in the Diabetes clinic was recruited and well trained on data collection techniques. The data collection instruments were pretested on five (5) patients in the Diabetes clinic to identify possible sources of errors that would arise during data collection. Those five patients were not part of the sample population and the questionnaire was administered to them to measure the inter-respondent agreement. The agreement of more than 78% was a measure that the items of the questionnaire would provide a picture on factors associated with non – adherence to antidiabetic medication in the study population.
Inclusion and exclusion criteria were strictly adhered to. A common pretested questionnaire which was edited prior to its use was used for data collection. The questionnaire was also checked for completeness before data collection to ensure valid data was obtained. Identification of participants was done by means of numerical codes. Details of participants were kept under lock and key for privacy and confidentiality purpose throughout the course of the study. There was no disclosure of participants’ identity to the public and all identities were removed before publication.
Data management and statistical analysis
Data on questionnaires was checked for completeness, coded and entered in Microsoft Excel version 2010, and then exported to stata version 13. Socio-demographic and clinical factors were summarized as means and standard deviation (for continuous variables). Percentages and frequencies were used for categorical variables. Descriptive statistics (means, frequencies and percentages) were used to determine prevalence of non-adherence and patient and disease information. The factors associated with non-adherence to antidiabetic medication were identified using logistic regression. Binary logistic Regression was carried out using stata. Prevalence Ratios were used to compare the prevalence of non-adherence across the independent variables. Factors with p-value ≤ 0.20 at bivariate logistic regression and with biological plausibility were considered for multivariate analysis. Those factors with p-value < 0.05 were considered significant.
Ethical considerations
This study was conducted in accordance with the Declaration of Helsinki (16). Approval to carry out the study was acquired from the Department of Pharmacy, Faculty of Medicine and finally from Mbarara University Research Ethics Committee (MUST-REC). After approval by the MUST-REC (Letter with reference number MUREC 1/7), permission was thought from the administration of Mbarara Regional Referral Hospital prior to data collection in the Diabetes mellitus clinic.
Precautions for prevention of Covid 19 transmission
Participants who were initially screened for body temperature and possible signs and symptoms of covid 19 were considered for data collection. These were further given more information on how covid 19 is transmitted and finally preventive measures of hand washing, wearing face mask and social distancing were always emphasized before any interaction with the study participants.