Adverse drug reactions and medication adherence to oral antidiabetic drugs in patients: A longitudinal study

The World Health Organization (WHO) has indicated that treatment adherence in most patients with type 2 diabetes (T2D) is low and may be affected by the presence of adverse drug reactions (ADRs) associated with hypoglycemic pharmacotherapy The aim of this study was to analyze the relationship between the degree of pharmacotherapeutic adherence and the appearance of ADRs in people with T2D. A three-month prospective study was conducted, in which pharmacotherapeutic adherence was assessed using an indirect method, while ADRs were identified and characterized through active pharmacovigilance in outpatients at a public hospital in southern Mexico. Patients with T2D between 18 to 60 years, of both sexes, under pharmacological treatment with metformin and/or glyburide were included. The incidence and characteristics of ADRs, as well as the degree of pharmacotherapeutic adherence, were analyzed. Comparative analysis was carried out between adherent and non-adherent patients, evaluating the presence or absence of ADRs using the Chi-square test or Fisher's exact test. 92 patients were included, 106 ADRs were detected in 42 patients, the cumulative incidence was 45.65%. The proportion of ADRs among non-adherent patients was significantly higher than adherent patients (Chi-square test = 4.64; p = 0.031) and the Gastrointestinal disorders was the System Organ Class most affected (48.11%). Causality of the ADRs was mostly "probable" and severity "mild" category was the most frequent. These results provide objective evidence on the relationship between poor adherence and a higher prevalence of adverse drug reactions (ADRs) to oral hypoglycemic treatment using real-world data.