Adverse drug reactions to anti-diabetic drugs are commonest in patients whose treatment do not adhere to diabetes management clinical guidelines: cross-sectional study in a tertiary care service in sub-Saharan Africa.

AIMS The study aimed to identify and describe adverse drug reactions and adherence to clinical guidelines in patients receiving treatment for type 2 diabetes mellitus (T2DM) in Cameroon. METHODS The method used was a cross-sectional study at a tertiary diabetes care service in Yaounde, Cameroon. Adult T2DM patients attending the diabetes clinic were interviewed using a pre-structured data collection form. Adverse drug reactions (ADRs) were self-reported by the patients. Naranjo's algorithm and Hartwig and Siegel's scale were used for assessment of causality and severity of ADRs, respectively. A blinded senior endocrinologist assessed whether treatment pattern of patients was "adherent" or not to local clinical guidelines for the management of diabetes. RESULTS Of a total of 350 patients enrolled into the study 61.1% were on oral hypoglycaemic agents only, 24.9% were on both oral hypoglycaemic agents and insulin, while 13.4% were on insulin alone. Metformin was used by 96.3% of the patients. Ninety patients reported 101 suspected ADRs. The proportion of ADRs among patients with poor adherence to clinical guidelines was higher than ADRs reported among adherent patients (Chi-square test = 7.3273; p = 0.007). Hypoglycaemia was more frequent ADR among non-adherent (25.7% of the suspected ADR) than adherent participants (11.6%). In the participants whose treatment pattern did not adhere to local clinical guidelines, ADRs were definite in 63.9%, probable in 16.6%, doubtful in 13.9% and possible in 5.6% of the cases. ADRs were moderate in 61.1% and severe in 19.4% of cases whose treatment pattern was non-adherent to clinical guidelines. INTERPRETATION Adverse drug reactions may be frequent in type 2 diabetes patients whose treatment pattern does not adhere to local clinical guidelines in Cameroon. Therefore, the promotion of active pharmacovigilance and the design of training activities to promote the appropriate use of medicines at hospital level in Cameroon could help to improve the management of diabetes and reduce the incidence of avoidable ADRs in the future.