Authors (including presenting author) :
Lo EHY(1), Fung PP(1)
Affiliation :
(1)Department of Pharmacy, Caritas Medical Centre
Introduction :
Dipeptidyl Peptidase-4 inhibitors are classified as special drugs within the Hospital Authority Drug Formulary (HADF) for the management of Type 2 Diabetics Mellitus (T2DM). They are considered as alternative to insulin after failure of optimal doses of sulphonylurea (SU) and metformin, or optimal doses of SU if metformin is intolerable /contraindicated; or as adjunctive to insulin to optimize control. DPP-4 inhibitor therapy should be discontinued if it fails to achieve HbA1c less than 8% within 6-8 months.
Objectives :
To evaluate prescribers’ compliance to the recommendations listed in the HADF version 13.3 on initiation and discontinuation of DPP-4 inhibitors in adults with T2DM
To evaluate the utilization pattern and assess the safety and efficacy of DPP-4 inhibitors
Methodology :
This was a single-centered, retrospective study. Medicines & Geriatric Specialist Out-Patient Clinic patients who were prescribed with DPP-4 inhibitors between 1 Sep 2016 and 31 Oct 2017 were included in the study. Recruited cases were reviewed to determine whether the initiation and continuation of DPP-4 inhibitors was in accordance to HADF recommendations. The appropriateness of dosage was reviewed with regard to renal function and concurrent medications. The efficacy of DPP-4 inhibitor was assessed by the change of HbA1c before and after treatment.
Result & Outcome :
294 patients were recruited in the study and 290 (98.6%) were indicated to initiate DPP-4 inhibitors as special drug. Among those patients, 278 (94.6%) had the DPP-4 inhibitors continued after 6-8 months in which, 152 (54.6%) were considered appropriate and 121 (43.5%) inappropriate. The mean change of HbA1c after 6-8 months was -1.0%. Almost all patients in the linagliptin and sitagliptin groups were prescribed with appropriate dosage. In the vildagliptin group, 46 (29.3%) were prescribed with inappropriate dosage. All of these patients received concomitant SU in which the dose of vildagliptin should be adjusted. Most patients had DPP-4 inhibitors initiated as indicated however only about half were continued appropriately. The efficacy of DPP-4 inhibitors was found similar to other literature. Almost all patients received appropriate dosage with respect to their renal function. When given with concurrent SU, one-third of the vildagliptin group did not have the dosage reduced.