Drugs for cardiovascular risk reduction in the diabetic patient

Allele frequency and genotype distribution of a common variant in the 3´-untranslated region of the SLC22A3 gene in patients with type 2 diabetes: Association with response to metformin

Background:

Organic cation transporter 3 (OCT3) is an excellent transporter for metformin, which is used as first-line therapy for type 2 diabetes (T2D). OCT3 genetic variants may influence the clinical response to metformin. This study aimed to determine the genotype and allele frequency of OCT3-564G>A (rs3088442) variant and its role in the glycemic response to metformin in patients with newly diagnosed T2D.

Materials and Methods:

Based on the response to metformin, 150 patients were classified into two groups: Sixty-nine responders (decrease in glycated hemoglobin [HbA1c] values by more than 1% from the baseline) and 81 nonresponders (decrease in HbA1c values <1% from the baseline). HbA1c levels were determined by chromatography. The variant OCT3-564G>A was genotyped using polymerase chain reaction - based restriction fragment length polymorphism.

Results:

The genotypes frequencies were 51.3% GG, 36% AG, and 12.7% AA. Allele frequency of major allele (G) and minor allele (A) in OCT3-564G>A variant was found to be 0.69 and 0.31, respectively. Fasting glucose, HbA1c, body mass index, and lipid profile in both GG genotypes and GA + AA group decreased significantly after 3 months of metformin therapy compared with baseline (P < 0.05). In both responders and nonresponders, HbA1c and fasting glucose levels were lower in patients with the GA + AA genotype than in those with the GG genotype; however, the differences were not statistically significant (P > 0.05).

Conclusion:

The A allele frequency (which may be a protective allele against coronary heart disease) in the Iranian diabetic patients was lower than Iranian, Caucasian and Japanese healthy populations. Metformin is useful in improving the lipid profile, in addition to its impacts in glycemic control, and these effects are regardless of OCT3-564G>A variant.

The Role of Metformin Response in Lipid Metabolism in Patients with Recent-Onset Type 2 Diabetes: HbA1c Level as a Criterion for Designating Patients as Responders or Nonresponders to Metformin

Background

In this study, we investigated whether response to metformin, the most frequently drug for diabetes treatment, influences the therapeutic effects of antilipidemic medication in newly diagnosed patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 150 patients with T2DM were classified into two groups following 3 months of metformin therapy (1000 mg twice daily): responders (patients showing ≥1% reduction in HbA1c from baseline) and nonresponders (patients showing <1% reduction in HbA1c from baseline). The patients received atorvastatin 20 mg, gemfibrozil 300 mg, or atorvastatin 20 mg and gemfibrozil 300 mg daily.

Principal Findings

HbA1c and fasting glucose levels were significantly different between baseline and 3 months among responders receiving atorvastatin; however, these differences were not statistically significant in nonresponders. Atherogenic ratios of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C; p = 0.002), total cholesterol to HDL-C (TC/HDL-C; p<0.001) and AIP (the atherogenic index of plasma; p = 0.004) decreased significantly in responders receiving atorvastatin than in nonresponders. Moreover, responders receiving atorvastatin showed a significant increase in HDL-C levels but nonresponders receiving atorvastatin did not (p = 0.007). The multivariate model identified a significant association between metformin response (as the independent variable) and TG, TC, HDL-C and LDL-C (dependent variables; Wilk's λ = 0.927, p = 0.036).

Conclusions

Metformin response affects therapeutic outcomes of atorvastatin on atherogenic lipid markers in patients newly diagnosed with T2DM. Metformin has a greater impact on BMI in responders of metformin compared to nonresponders. Adoption of better therapeutic strategies for reducing atherogenic lipid markers may be necessary for metformin nonresponders.

National trends in treatment of type 2 diabetes mellitus, 1994-2007

BACKGROUND

Diabetes mellitus is common, costly, and increasingly prevalent. Despite innovations in therapy, little is known about patterns and costs of drug treatment.

METHODS

We used the National Disease and Therapeutic Index to analyze medications prescribed between 1994 and 2007 for all US office visits among patients 35 years and older with type 2 diabetes. We used the National Prescription Audit to assess medication costs between 2001 and 2007.

RESULTS

The estimated number of patient visits for treated diabetes increased from 25 million (95% confidence interval [CI], 23 million to 27 million) in 1994 to 36 million (95% CI, 34 million to 38 million) by 2007. The mean number of diabetes medications per treated patient increased from 1.14 (95% CI, 1.06-1.22) in 1994 to 1.63 (1.54-1.72) in 2007. Monotherapy declined from 82% (95% CI, 75%-89%) of visits during which a treatment was used in 1994 to 47% (43%-51%) in 2007. Insulin use decreased from 38% of treatment visits in 1994 to a nadir of 25% in 2000 and then increased to 28% in 2007. Sulfonylurea use decreased from 67% of treatment visits in 1994 to 34% in 2007. By 2007, biguanides (54% of treatment visits) and glitazones (thiazolidinediones) (28%) were leading therapeutic classes. Increasing use of glitazones, newer insulins, sitagliptin phosphate, and exenatide largely accounted for recent increases in the mean cost per prescription ($56 in 2001 to $76 in 2007) and aggregate drug expenditures ($6.7 billion in 2001 to $12.5 billion in 2007).

CONCLUSIONS

Increasingly complex and costly diabetes treatments are being applied to an increasing population. The magnitude of these rapid changes raises concerns about whether these more costly therapies will result in proportionately improved outcomes.

Heart failure in the diabetic patient

This review examines the extent of the increased rate of heart failure (HF) in the diabetic patient, along with the possible causes for this increase and the poor prognosis associated with HF. Also reviewed are the therapies that are available for the treatment of diabetic HF and whether intensifying the use of these therapies might improve the worsened clinical outcomes for the patient who has diabetes.