A total of 257 study participants were recruited with 100% response rate. Majority (253, 98.4%) of participants had T2DM and almost two thirds (160, 62.3%) had been diagnosed with diabetes mellitus for less than five years. Majority (214, 83.3%) of the participants had comorbidities of which hypertension (143, 66.8%) was the most common. One quarter (50, 25.5%) of the participants reported that drug(s) being expensive was the cause of antidiabetic medication non-adherence and less than one quarter (38, 19.4%) ascribed non-adherence to not understanding instruction(s) on how to take prescribed medicine(s). More than one third (98, 38.1%) of the participants were non-adherent to their antidiabetic medication. Multivariate logistic regression revealed that age above 60 years (AOR = 6.26, 95%CI = 1.009–39.241, P = 0.049) and duration of diabetes mellitus of above 5 years since diagnosis (AOR = 1.87, 95%CI = 1.034–3.391, P = 0.038) were independently associated with antidiabetic medication non adherence.
More than one-third (38.1%) of participants in our study were determined to be non-adherent to their antidiabetic medication. Reasons for non-adherence ranged from; drugs being expensive for patients to buy on daily basis (25.5%), lack of understanding of prescription instructions (19.4%), unavailability of free antidiabetic medicines in public hospitals (16.3%), forgetfulness (12.2%) and patients’ preference for not following prescription instructions (12.2%).The findings in our study, revealed a higher prevalence of non-adherence to antidiabetic medication compared to similar studies in UAE, Egypt, Ghana, Mulago Hospital in Uganda, and Tanzania; which reported between 16.0% and 31.5% prevalence of medication non-adherence among diabetes mellitus(4, 5, 13, 17, 18). Perhaps this may be due to differences in the study populations and the study settings of different studies. Findings of our study in which majority (214, 83.3%) of the participants had comorbidities are comparable to the results of the study by (19)where comorbidities were significantly linked to antidiabetic medication non-adherence. The explanation could be that, the number of drugs taken by each patient is dependent on comorbidities. Therefore, a patient with a complex regimen is challenged to continue adhering to all prescribed medications. Multiple medications could contribute to non-adherence since such patients have divided commitment to managing several comorbidities. Also, since majority of our study population had low or no formal education (166,64.7%), this could explain the high levels of non-adherence to antidiabetic medications as further reported by previous studies in Ghana (20). The reason for this finding could be that as the antidiabetic regimen becomes complex, those with higher level of education are expected to easily understand such and thus effectively follow their treatment regimen. However, the findings of our study are notably lower, with the prevalence of non-adherence to antidiabetic medication at 38.1% compared to 48–68.8% prevalence, as reported from multiple studies in Bosnia & Herzegovina, India, Saudi Arabia and Ethiopia(8, 9, 21, 22). This difference might be that in our study, patients regularly received free antidiabetic medications whenever available at the Diabetes clinic. Free supply of antidiabetic medicines is believed to reduce the level of non-adherence among patients (Kalyango et al., 2008). The other reason might be that in our study, patients were well organized in a patient association that provided psychological support and counseling to patients. The lower prevalence of non-adherence in our study settings could also be explained by the lower levels of forgetfulness (12.3%) and lack of finances (25.5%), as compared to similar studies in Sudan, Ghana, and Saudi Arabia, which reported 30.7–66.7%, and 23.8–25.6% frequencies of forgetfulness and lack of finances, respectively(17, 23, 24). Since our study population majorly consisted of the female gender (168, 65.37%); findings from our study revealed that the female gender was 57 % less likely to non-adhere to their antidiabetic medication (AOR = 0.57 95%CI = 0.312–1.044 p-value = 0.069). This is in agreement with findings by (25), stating that the female gender were more adherent to their antidiabetic medications, possibly due to the reason that most females spent most of their time at home and are thus more likely to follow prescription instructions agreed upon with the prescribers due to convenient home environment.
Multivariate logistic regression revealed that, increasing age above 24 years had a positive association with likelihood of non- adherence to antidiabetic medication. Age groups between 24–60 years and above 60 years were 1.1 times (AOR = 1.19, 95% CI = 0.204–6.962, p-value = 0.845) and 6.2 times (AOR = 6.29 95% CI = 1.009–39.241 p-value = 0.049) more likely to be non-adherent to their antidiabetic medication, respectively. This finding in our study may be due to the fact that older adults are more likely to forget to take their medication and also older adults in our setting are less financially capable to access medications from drug outlets, as prescribed by the healthcare provider. This will as well explain the contrasting findings in a previous study in Ethiopia, where older adults were more likely to be adherent to their antidiabetic medication due to the possible difference in social-economic support to the elderly people (22). Duration of diabetes mellitus for more than 5years since diagnosis was also significantly associated with non-adherence to antidiabetic medication (AOR = 1.87, 95% CI = 1.034–3.391, P = 0.038). this is in agreement with the study from Saudi Arabia (3, 24). It demonstrates that, the longer the duration of diabetes mellitus, the more the rate of non-adherence. This finding may be explained by the anxiety and fear that patients experience during early years following diagnosis and thus become committed to managing their disease but the commitment gradually wears out as they adapt to the burden of the disease and non-adherence emerges. Surprisingly, in the current study, being unemployed (AOR = 0.37, 95%CI = 0.139–0.977, p-value = 0.045) was protective and therefore less likely to lead to non-adherence to antidiabetic medication. The explanation could be that unemployed patients usually have enough free time and were thus more likely to remember to take their antidiabetic medication.
Mean HbA1c of those who were non adherent was 9.43%, their mean FBG was 10.01 Mmol/l, P = 0.01 and was significantly associated with antidiabetic medication non-adherence