Treatment intensification in patients with type 2 diabetes who failed metformin monotherapy

Aim: To evaluate the time to and factors associated with treatment intensification in patients with type 2 diabetes who failed metformin monotherapy. Methods: In a retrospective analysis using a large US electronic medical record database, eligible patients included those with type 2 diabetes and an HbA(1c) of >= 7.0% or at least two fasting blood glucose levels of >= 126 mg/dl while on metformin monotherapy for at least 6 months within the period of 1 January 1997 to 31 December 2008. Time to treatment intensification was calculated as the time between index date (date on which HbA(1c) >= 7% after metformin monotherapy for at least 6 months) and first prescription for additional antihyperglycaemic agent during follow-up period. All patients were required to have data for at least 12 months prior to and following the index date. A Cox proportional hazards model was employed to determine patient baseline characteristics associated with time to treatment intensification. Results: Of the 12 566 patients identified, mean age at index date was 63 years and 51% were female. Mean index HbA(1c) was 8.0% overall, with 66, 19 and 15% of patients having an index HbA(1c) of 7 to <8%, 8 to <9% and >= 9%, respectively. Median time to treatment intensification was 14.0 months overall and 19.0, 8.7 and 4.5 months for patients with index HbA(1c) of 7 to <8%, 8 to <9% and >= 9%, respectively. Factors associated with treatment intensification included higher index HbA(1c), younger age, higher Charlson co-morbidity index, metformin daily dose >= 1500 mg and later index date (all p < 0.05). Conclusions: In US clinical practice, median time to receive additional antihyperglycaemic medication is more than 1 year for patients with type 2 diabetes who failed metformin monotherapy.