This transcript has been edited for clarity.
I usually report five or six studies in the field of neurology that were published in the last months, but July was a vacation month.
I decided to cover another topic, which is the role of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists beyond diabetes and obesity, and in particular, for the field of neurology and psychiatry. Until a few years ago, the treatment of diabetes with traditional antidiabetic drugs was frustrating for vascular neurologists.
These drugs would lower glucose and had an impact on small-vessel disease, but they had no impact on large-vessel disease, stroke, and vascular mortality. This changed with the sodium-glucose cotransporter 2 antagonists because these drugs were not only effective for diabetes, but they also lowered cardiac mortality, in particular, in patients with cardiac failure.
The next generation of antidiabetic drugs were the GLP-1 receptor agonists and the combined GIP/GLP-1 receptor agonists. These two polypeptides and their receptors play a very important role in diabetes and in obesity. The receptors are found not only in the pancreas but also in the intestinal system, the liver, and the central nervous system.
We have a number of preclinical models, mostly in transgenic mice, which show that these drugs are not effective only in diabetes and obesity, but also in liver disease, kidney failure, and neurodegenerative diseases. GLP-1 receptor agonists also have powerful anti-inflammatory properties. These drugs reduce body weight, and they have positive effects on blood pressure and lipid metabolism.
In the studies on the use of GLP-1 receptor agonists in diabetes, a meta-analysis with more than 58,000 patients showed a significant risk reduction for stroke compared with placebo, and this risk reduction was in the range of 80%.
Stroke, Smoking, and Alcohol
A meta-analysis on the use of GLP-1 receptor agonists in over 30,000 nondiabetic patients with obesity found a significant reduction in blood pressure, mortality, and the risk of myocardial infarction. There was no significant decrease in the risk of stroke, but most probably this is due to the fact that strokes are much less frequent in obesity than in diabetes.
You all know that obesity is also a major risk factor for sleep apnea syndrome. Recently, two large studies with the GIP/GLP-1 receptor agonist tirzepatide found a significant improvement in sleep apnea syndrome compared to placebo, regardless of whether patients needed continuous positive airway pressure therapy or not.
In the therapy studies on diabetes and obesity, there were indications that some smokers in the studies stopped their nicotine consumption. A small pilot study with exenatide in 84 overweight patients who were smokers showed that 46% of patients on exenatide stopped smoking compared with 27% in the placebo group. This could be an indication that GLP-1 receptor agonists have activity on the reward system in the brain. Currently, there are a number of larger placebo-controlled trials ongoing.
Another aspect is alcohol consumption. An epidemiologic study in Denmark using data from the National Health Registry showed that the incidence of alcohol-related events decreased significantly in almost 40,000 patients with diabetes when they were treated with GLP-1 receptor agonists compared with other antidiabetic drugs.
A retrospective cohort study from the United States with over 80,000 patients with obesity showed that treatment with GLP-1 receptor agonists was associated with a 50%-60% lower risk for occurrence or recurrence of high alcohol consumption. There is only one small study with exenatide, which was not really informative.
There are a number of studies underway for GLP-1 receptor agonists compared with placebo in patients with alcohol dependence or alcohol consumption. Preclinical models also indicate that these drugs might be effective in cocaine abuse, and there is one placebo-controlled study ongoing.