Antidiabetics' usage in type 2 diabetes mellitus: Are prescribing guidelines adhered to? A single centre study

The primary aim of this study was to examine the prescribing patterns of antidiabetic agents (AA) in this hospital according to current prescribing contraindications (PCI). The secondary aims are to assess factors affecting the prescribing of AA and to evaluate the pharmacist impact on their prescribing.

A retrospective cross sectional study was performed to review all prescribed AA over a 3 month period. Data extracted from medical records included: patients' demographics, management and pharmacists' interventions. Appropriateness of prescribing was determined according to the AA prescribing information of the Medical Index of Medical Specialities (MIMS).

A total of 314 AA were examined, of which 74(23%) orders were prescribed despite contraindications. Metformin was the AA to have the most PCI in dosage adjustments in renal impairment (RI). Logistic regression analysis showed patients with severe RI were less likely to be prescribed metformin (OR = 0.115 95%CI(0.048-0.274) P < 0.01), instead insulin was preferred (OR = 2.210 95%CI (1.028-4.751) P < 0.05). Insulin was also more likely to be prescribed in patients with hypertension and hyperglycaemia (OR=2.005 95%CI(1.005-4.001) P < 0.05, OR = 3.535 95%CI(1.756-7.113) P < 0.01) respectively. Sulphonylureas were less likely to be prescribed in patients with cardiovascular disease (OR = 0.339 95%CI(0.163-0.708), P < 0.01. There was low PCI in the other AA. Pharmacists reviewed 89% of AA. PCI was lower in this group compared to those with no pharmacist input (23% vs 28%).

The audit showed good adherence to PCI. Pharmacist involvement has a positive impact on AP. Prescriber education is required in relation to dosage adjustments of AA in RI.