Type 2 Diabetes Haptoglobin Phenotype and Vitamin E

There exists ample evidence supporting the hypothesis that vitamin E supplementation to Hp 2-2 DM individuals will reduce the incidence of stroke, myocardial infarction and cardiovascular death. Data regarding the association between the Hp 1-1 and 2-1 phenotypes and vitamin E treatment on cardiovascular outcomes such as MI, stroke and CV death is lacking. Furthermore there is no data correlating Hp phenotype, vitamin E and HDL function, structure and oxidation. We wish to evaluate the effect of vitamin E treatment on all diabetic patients with type 2 diabetes on HDL function, structure and oxidation and correlate these parameters to Hp phenotype.

This study will be the first study to prospectively evaluate the interaction of the Hp phenotype and vitamin E in type 2 diabetic patients. As such we wish to evaluate the surrogate marker of reverse cholesterol transport as evidence to the function or dysfunction of the HDL in a relatively small scale study before engaging in a large scale clinical outcome study.

Study objectives. To evaluate the effect of vitamin E treatment on HDL function of reverse cholesterol transport.

Test product. Natural Source Vitamin E (d-α-tocopherol) 400IU administered P.O. as soft gel capsules.

Study population. The study population will be comprised of men and women, age 55 and above with type 2 DM. 90 DM individuals will comprise the treatment phase of the study and will be divided into 30 patients in each Hp phenotype (1-1, 2-1, 2-2).

All 90 patients will be randomized in a double blind fashion into two treatment groups, Vitamin E Natural source 400IU per day versus matching placebo assuring that there will be an equal amount of patients of each phenotype allocated to placebo and Vitamin E.

Study power Calculation_We have calculated that a sample of a total 90 patient (30 in each phenotype) will be required to identify a 30% difference in Reverse Cholesterol Transport between the groups and a statistically significant interaction between phenotype and treatment, with an 80% power and a two sided p value of <0.05.

Study administration. Eligible patients will be identified using the ICARE study database with the help of the ICARE study coordinator at Clalit Health Services. We will identify patients from the 3 Hp phenotypes (those patients were Hp typed as part of the ICARE study and their Hp type is on file). We will then call the patients and they will be asked questions according to the screening questioner to be identified as eligible according to inclusion/exclusion criteria. Those eligible will be invited to the Technion faculty of medicine and will be then recruited to the study after they agree and sign the Informed Consent Form (ICF). Patients will give a blood sample of 50cc of blood at enrollment which will serve as baseline for testing reverse cholesterol transport as well as HDL structure and oxidation. Patients will then be randomized to vitamin E or placebo in a double blinded manner. We will recruit consecutive eligible patients from the ICARE registry till we reach the number of 30 patients in each phenotype and a total of 90 patients. For all 90 treated patients Blood tests (50cc of blood) will be performed after 3 months of treatment, then cross over for an additional 3 months of treatment which in its end the last blood test will be performed (again 50cc). Patients who participate in the treatment phase of the study will have to arrive at the clinic 3 times (baseline and randomization visit, end of first treatment visit and end of second treatment visit).

Analysis. Reverse cholesterol transport results will be compared within and between the groups using paired and unpaired student's t-tests as appropriate. The p for interaction between the 3 phenotype groups and treatment will also be determined.