Glucophage XR® Observational Study

• Proportion of patients who experience at least one gastrointestinal side effect [ Time Frame: 12 weeks ] [ Designated as safety issue: Yes ]
  

• Proportion of patients who discontinue Glucophage XR® prematurely, defined as less than 12 weeks, due to side effects. [ Time Frame: 12 weeks ] [ Designated as safety issue: Yes ]
  
• Incidence of side effects [ Time Frame: 12 weeks ] [ Designated as safety issue: Yes ]
  
• Change of Hemoglobin A1c level from baseline after at least 12 weeks of Glucophage XR® therapy [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
  

Metformin (Glucophage) is the standard first line therapy for patients with type 2 diabetes mellitus. The landmark UK Prospective Diabetes Study Group demonstrated significant reduction in the risk of myocardial infarction and overall mortality in overweight patients with type 2 diabetes treated with metformin and metformin was more effective in controlling blood glucose compared with lifestyle only diet-based policy. The observed improvement of blood glucose was not associated with weight gain or hypoglycaemia in contrast to treatment with either a sulphonylurea or insulin.

It is well accepted that patients' compliance with therapy tends to decrease as the dosage frequency increases and that regimens should be simplified as far as possible to support good compliance with therapy. The use of an extended-release formulation of metformin (Glucophage XR®) may support the simplification of treatment for patients by allowing a once-daily administration of metformin.

Although patients taking metformin had significantly lower fasting and postprandial plasma glucose and hemoglobin A1C concentrations, they also had a higher prevalence of Gastrointestinal (GI) side effects. The most commonly reported symptoms was diarrhea (53,2 % compared to 11,7% on placebo). In a study employing self-administered questionnaires to ascertain GI symptoms in patients with type 2 diabetes approximately 20% of those taking immediate-release metformin reported diarrhea as the most common symptoms. Although less than 5% of patients discontinue metformin treatment for this reason, such adverse events can be troublesome, may limit the dosage of metformin and may impair compliance with therapy. Glucophage XR may lead to improved tolerability, by smoothing the peaks and troughs in metformin plasma concentrations and delaying the achievement of peak plasma concentration, compared with an immediate-release formulation. Initial placebo-controlled clinical trials with Glucophage XR indicate that 9,6% patients reported diarrhea (compare to 1,5% on placebo).

Thus, the use of Glucophage XR® may provide benefits in terms of improved patient management, by enabling once-daily dosing and reducing the incidence of gastrointestinal side effects for some patients. A prospective observational study will be valuable to provide information on the day-to-day experience of using Glucophage XR® in the management of this patient population. The data may provide an insight into the use of Glucophage XR® in routine clinical practice in Thailand.