The PRuDENTE study proposes to assess if metformin therapy a viable, efficient and cost-effective intervention to decrease the incidence of type 2 diabetes (DMT2) in adult subjects with obesity and pre-diabetes in Mexico City. Half of the individuals recruited will receive as intervention, metformin and lifestyle modification therapy and the other half will receive only lifestyle modification therapy.

Diabetes in Mexico is considered a national emergency given its high prevalence, incidence, mortality and costs. Mexico has one of the highest prevalence of diabetes; in only 6 years (2000 to 2006) this prevalence increased from 7.5% to 14.4%. In 2015, 151 deaths per 100,000 inhabitants occurred in Mexico due to diabetes complications.

Metformin is a hypoglycemia drug and it´s the first line medication for the treatment of type 2 diabetes.There is currently a significant amount of evidence that metformin administration reduces the progression from pre-diabetes to diabetes and, despite its monotherapy being less effective than lifestyle changes, the good biosafety profile and low cost have made it the drug of choice in a joint treatment.

The PRuDENTE study proposes to perform this intervention in a real environment in the clinics of the first level of care of the Ministry of Health of the Government of Mexico City, in order to provide evidence about the cost-effectiveness of metformin as a public health intervention for the prevention of diabetes.

Inclusion Criteria:

• Having received primary care in the chosen health center (ideally two or more visits to that clinic in the prior year).
• Subscribers to "Seguro Popular" ( Mexican national health insurance)
• Body mass index >=30 kg / m2
• Results of fasting serum glucose with values for pre-diabetes diagnosis (glucose between 100 and 125 mg / dl)

Optional:

• Family history of DMT2 (1st grade relative).
• Previous diagnosis of hypertension or dyslipidaemia.
• Have received antihypertensive medication and / or for cholesterol / lipids.
• History of gestational diabetes mellitus.

Exclusion Criteria:

• Renal insufficiency (Glomerular Filtration Rate (GFR) <30 ml/min).
• Known hepatic impairment or altered liver enzymes (aspartate aminotransferase (AST) AST or alanine aminotransferase (ALT) three times above normal values)
• Active alcoholism or drug addiction
• Allergies or previous known intolerance to exercise or metformin.
• Current pregnancy.
• Plans to leave the area in the next three years.
• Previous diagnosis of type 2 diabetes mellitus