Korean study shows: Common diabetes medication could reduce dementia risk

SGLT-2 inhibitors help patients manage diabetes by preventing the kidneys from reabsorbing the sugar produced by the body. Photo used for representative purposes only | Image credit: Getty Images/iStockphoto

A common diabetes drug may prevent dementia, with longer treatment bringing more benefits, a study in Korea suggests.

The study, which used data from South Korea's national health insurance database, was published in the British Medical Journal.

In more than 200,000 adults ages 40 to 69 with type 2 diabetes, researchers found that the risk of dementia was 35 percent lower when taking a class of drugs known as sodium-glucose cotransporter-2 inhibitors, or SGLT-2 inhibitors, than when taking dipeptidyl peptidase-4 inhibitors, or DPP-4 inhibitors, also known as gliptins.

In addition, treatment with SGLT-2 drugs over a longer period of time was shown to have more pronounced effects – treatment for more than two years reduced the risk of dementia by 48 percent. Examples of SGLT-2 drugs available in India include remogliflozin and dapagliflozin, while DPP-4 drugs include sitagliptin, vildagliptin and teneligliptin.

Randomized controlled trials required

However, the researchers, including those from Seoul National University's Bundang Hospital, warned that the effects may have been overestimated and said randomized controlled trials (RCTs) are now needed to confirm these findings. RCTs are considered the gold standard of clinical trials.

The team found that details about patients' health behaviors, such as smoking and alcohol habits, and the duration of their diabetes were not fully available.

However, the authors pointed out that this was a large study based on nationally representative data, which also included relatively young people with type 2 diabetes, and that the results were extremely consistent between subgroups.

SGLT-2 inhibitors help patients manage diabetes by preventing the kidneys from reabsorbing the sugar produced by the body. The excess sugar is then excreted in the urine. DPP-4 inhibitors, on the other hand, work by blocking the DPP-4 enzyme, helping the body to increase insulin levels after a meal.

SGLT-2 drugs are widely used in India to treat diabetes.

For the study, researchers used the Korean National Health Insurance Service database to identify over 110,000 pairs of adults with an average age of 62 and type 2 diabetes who were free of dementia and had started taking an SGLT-2 or DPP-4 drug between 2013 and 2021. All participants were followed for about two years to see who developed dementia.

“This large population-based cohort study of adults aged 40 to 69 years with type 2 diabetes found a 35 percent reduced risk of dementia associated with the use of SGLT-2 inhibitors compared with DPP-4 inhibitors,” the authors wrote.

The researchers also found that the risk of Alzheimer's disease associated with SGLT-2 was 39 percent lower and the risk of vascular dementia 52 percent lower compared to DPP-4 inhibitors.

The most common form of dementia is Alzheimer's disease, while vascular dementia is a condition in which brain function is impaired due to damaged blood vessels that block blood flow and oxygen supply.

In addition, the researchers found that patients who took SGLT-2 drugs for more than two years had a 48 percent lower risk of dementia, while patients who took these drugs for two years or less had a 43 percent lower risk.

The result suggests that longer duration of diabetes treatment with SGLT-2 drugs may have more pronounced effects, the authors said.

No clear conclusions drawn about cause and effect

Since this was an observational study, no clear cause-and-effect conclusions could be drawn, the authors noted, calling for randomized controlled trials to confirm their findings.

On average, the incidence of dementia among participants taking SGLT-2 drugs was 0.22 per 100 people over a one-year period. Among those taking DPP-4 blockers, the rate was 0.35 per 100 people over a one-year period, according to the study.

A study published in February in the journal PLoS ONEIt is estimated that there are 340,000 elderly people aged 60 and above in India living with mild cognitive impairment – ​​the stage before dementia – that affects their daily life and activities in some way.