Primary Outcome Measures:
- Cognitive decline: rate of decline in tests of memory and executive function in the glycemic treatment group over a 4 year period
- MRI brain changes: total brain volume (cerebral atrophy) in the glycemic treatment group over a 4 year period
Secondary Outcome Measures:
- Cognitive decline: rate of decline in tests of memory and executive function in the blood pressure and lipid treatment groups over a 4 year period
- MRI brain changes: total brain volume (cerebral atrophy) in the blood pressure treatment group over a 4 year period
Type 2 diabetes and cognitive impairment are two of the most common chronic conditions found in persons 60 years and older. Approximately 18%-20% of older persons suffer from diabetes. And, in the general population, the prevalence of cognitive impairment, measured with the simple Mini-Mental State Exam, increases steadily from 5% at 65 years to 15% percent at 80 years of age. Many persons with cognitive impairment go on to develop dementia, which doubles in incidence and prevalence every additional 5 years of age. Studies suggest diabetes is one risk factor for cognitive impairment and dementia.
Further, the brains of people with diabetes are at risk for complications following repeated hypoglycemic events. Magnetic Resonance Imaging (MRI) provides a measure of the structural changes in the brain that form the anatomical substrate for cognitive decline and dementia. At present there are a few MRI studies showing people with diabetes have increased risk for brain atrophy and (mainly silent) lacunae.
The comparison of standard diabetes care with intensive diabetes care will be made in a sub-sample of 2800 people (including 640 for MRI) with diabetes currently participating in the ongoing National Heart Lung and Blood Institute (NHLBI) Action to Control Cardiovascular Risk in Diabetes (ACCORD). ACCORD is designed to evaluate whether more intensive glucose, blood pressure and lipid management can reduce cardiovascular disease in people with diabetes. Participants in ACCORD-MIND will have already been randomly assigned to either the intensive or standard diabetes care in the ACCORD trial, and will already have been randomized to either the blood pressure or lipid intervention arms (see NCT00000620). ACCORD-MIND will test these patients for cognitive function and changes in brain structure.
Tests of cognitive function measure memory and executive function, which includes speed of processing, attention, planning, and concentration. They are indicators of how well a person performs various tasks in daily life. Cognitive impairment is also predictive of future onset of dementia. In diabetes, cognitive impairment may compromise an individual's ability to manage his/her disease, an important factor that should be incorporated into an analysis of the trial efficacy.
MRI is a safe, non-invasive method to assess the structural characteristics of the brain. With MRI, investigators may begin to identify vascular lesions and brain atrophy that form the anatomical basis for cognitive changes that may be associated with the ACCORD treatments.