Preventing type 2 diabetes with low-dose combinations

Prediabetes: to treat or not to treat?

The incidence of diabetes is continuously increasing worldwide. Pre-diabetes (defined as impaired glucose tolerance, impaired fasting glucose or both) represents an intermediate state, which often progresses to overt diabetes within a few years. In addition, pre-diabetes may be associated with increased risk of microvascular and macrovascular complications. Thus, reverting a pre-diabetic state as well as preventing the development of diabetes represents enormous challenge for the clinician. Lifestyle modification in pre-diabetic individuals was found particularly effective in the prevention of diabetes. However, compliance to lifestyle modification measures can be a crucial problem in the everyday clinical practice, especially in developing countries. During the last decade many studies support the use of anti-diabetic treatment schemes in pre-diabetic subjects to be advantageous. The American Diabetes Prevention Program (DPP) as well as other minor studies and meta-analyses has convincingly demonstrated the efficacy of metformin in this patient group. In addition, results of the 10 year DPP follow up have recently been published, demonstrating the long term safety and sustainability of metformin treatment benefits in this population. In contrast to metformin, the evidence from the use of other anti-diabetic agents (thiazolidinediones, a-glucosidase inhibitors, incretin mimetics) in pre-diabetic individuals is rather inadequate and prospective data is further needed. Furthermore, large scale studies with hard clinical endpoints are needed to delineate the effect of pre-diabetes treatment on macro- and microvascular complications. In conclusion, several strategies of patient management, mainly lifestyle modification and pharmacological interventions can prevent diabetes development in subjects diagnosed with pre-diabetes or even revert pre-diabetic state. However, whether this biochemical improvement can be translated into actual clinical benefit remains to be established.

Waist circumference and metabolic risk factors have separate and additive effects on the risk of future Type 2 diabetes in patients with vascular diseases. A cohort study

AIMS

To assess the effect of various measures of adiposity and of metabolic risk factors, both separately and in combination, on the risk of future Type 2 diabetes in patients with manifest vascular diseases.

METHODS

This was a prospective cohort study in 2924 patients (mean age 59 ± 12 years) with manifest atherosclerosis. Metabolic risk factors were defined according to National Cholesterol Education Program criteria for the metabolic syndrome. Incidence of Type 2 diabetes was assessed by questionnaire and subsequent verification.

RESULTS

During a median follow-up of 4.9 years (range 3.0-7.6 years) there were 178 cases (6.1%) of incident Type 2 diabetes. An increase with 1 sd waist circumference showed a strong association with incident Type 2 diabetes in both men (hazard ratio 2.45, 95% CI 1.97-3.04) and women (hazard ratio 1.77, 95% CI 1.38-2.26). Compared with patients with normal (i.e. below the National Cholesterol Education Program criteria for abdominal adiposity) waist circumference and < 3 metabolic risk factors, both patients with normal waist circumference and ≥ 3 metabolic risk factors and patients with high (i.e. above the National Cholesterol Education Program criteria for abdominal adiposity) waist circumference and < 3 metabolic risk factors had an increased risk of Type 2 diabetes (hazard ratio 2.44, 95% CI 1.37-4.36 and hazard ratio 3.61, 95% CI 2.23-5.85, respectively). Patients with both high waist circumference and ≥ 3 metabolic risk factors had the highest risk of developing Type 2 diabetes (hazard ratio 10.76, 95% CI 6.95-16.64).

CONCLUSIONS

In patients with manifest atherosclerosis, both presence of ≥ 3 metabolic risk factors and presence of a high waist circumference alone are associated with increased risk for developing Type 2 diabetes. The combined presence of ≥ 3 metabolic risk factors and high waist circumference, which is present in 15% of patients, is associated with a 10-fold increased risk of future Type 2 diabetes. To identify patients with manifest atherosclerosis at the highest risk of developing Type 2 diabetes, fat distribution in combination with metabolic risk factors should be considered.