Do Diabetes Medications Damage Kidneys and Pancreas? An Endocrinology Professor Addresses Misconceptions About Drug Treatment

When starting diabetes drug treatment, it is natural to feel psychological anxiety or resistance. Appearing in a video for the health medical specialty channel HiDoc, Professor Son Jang-won of the Department of Endocrinology at The Catholic University of Korea, Bucheon ST. Mary’s Hospital, noted that due to the recent overflow of information, there seem to be many misconceptions regarding diabetes medications, and he addressed representative myths surrounding drug treatment. Professor Son serves as the Secretary General of the Korean Diabetes Association.

Lifelong medication, stigma, symbolism of insulin... reasons for avoiding drug treatment

According to Professor Son, patients are extremely worried about whether they truly have to take medication for the rest of their lives. Being diagnosed as a diabetes patient feels like being branded with the stigma of a chronic disease sufferer, and the feeling that taking medication is like crossing a certain line creates resistance. The inconvenience and cost of daily medication, as well as the stigma effect in social life such as at school or work, are also concerns.

When it comes to starting insulin injection therapy instead of oral medication, the psychological resistance can be much greater. He explains that the injection itself can be frightening and may be perceived as making the treatment more complex, and there is also the symbolism of insulin therapy—the feeling that one has reached the end of treatment—as well as the burden of hypoglycemia caused by insulin. Circumstances vary by patient. Younger patients find it difficult to face the long period of having to take medication for the rest of their lives, while elderly patients, who are already taking several medications, wonder if starting diabetes treatment now will offer significant benefits. Since gestational diabetes cannot be treated with oral medication and requires insulin injections, many expectant mothers find it difficult to start treatment due to worries about potential problems for the fetus.

Problems that can arise if treatment is delayed

Professor Son emphasized that diabetes is both a chronic disease and a progressive disease. He stated that if blood sugar is not sufficiently managed in the early stages, not only can small microvascular problems like diabetic nephropathy or neuropathy (such as numbness in hands and feet) occur, but the risk of large vessel diseases like heart or cerebrovascular diseases can also increase. While many refuse drug treatment in the early stages of diabetes because there are no particular symptoms, he noted that in reality, there are many cases with uncomfortable symptoms. After eating, patients may feel significant fatigue, experience very dry skin and pruritus (itching), or depending on the patient, experience changes in bowel habits, indigestion, or urinary problems. For middle-aged men, erectile dysfunction is also one of the major concerning complications, and as the number of elderly patients increases, decreased cognitive function, dementia, and an increased risk of various cancers can also become problems, making early drug treatment extremely important, according to Professor Son's explanation.

The misconception that 'diabetes medication damages the kidneys'

Regarding the myth that diabetes medication damages the kidneys, Professor Son explained that if one suffers from diabetes for a long time, diabetic nephropathy (diabetes kidney disease) can develop as a complication, and if kidney disease occurs while taking medication, people tend to think it is because of the medication rather than the diabetes. He compared it to seeing a firefighter dispatched to a fire scene and thinking the firefighter caused the fire, stating that it is necessary to understand it as a complication of diabetes rather than a side effect of the medication.

There is another reason for the misconception. Many diabetes medications are excreted through the kidneys. Since Metformin, a representative first-line treatment, is also excreted through the kidneys, the dosage may be reduced if the glomerular filtration rate (GFR), which indicates kidney function, falls below 45 or 30, and patients may be told to stop taking it when undergoing a CT scan. Professor Son pointed out that these safety measures are sometimes misinterpreted as the medication being bad for the kidneys.

SGLT2 inhibitors, diabetes medication that protects the kidneys

Professor Son cited organ protection as the area where the paradigm of diabetes treatment has changed most significantly recently. While previous treatments focused only on lowering blood sugar, recent focus has shifted toward medications that can prevent or reduce various complications and problems in various organs that can arise from diabetes. Among these, SGLT2 inhibitors and GLP-1 class incretin agents are gaining spotlight, and he explained that the effects of SGLT2 inhibitors are particularly distinct regarding diabetic nephropathy.

According to Professor Son, SGLT2 inhibitors inhibit the reabsorption of sodium and glucose in the kidneys and excrete them through urine, which results in lowering the glucose concentration in the blood. He used an analogy that if the glomerulus is thought of as a fine filter in a water purifier, the filter gets damaged when overloaded, but SGLT2 inhibitors reduce this overload so the filter can be used safely for a long time. He explained that during the first 4 to 6 weeks of treatment, the glomerular filtration rate may temporarily drop by about 10–20%, which could be mistaken for worsening kidney function, but it usually recovers and, in the long term, actually plays a role in protecting the kidneys.

However, Professor Son emphasized that these medications do not offer the same benefits to everyone and that side effects must also be known. Women may develop genital fungal infections, so they must consult their doctor if they experience uncomfortable symptoms. Furthermore, in patients who maintain SGLT2 inhibitor monotherapy while fasting for a long time or those requiring insulin therapy, or in situations requiring surgery, it can cause serious complications such as ketoacidosis even when blood sugar levels are fine. He added that GLP-1 class incretin drugs also reduce cardiovascular events in addition to blood sugar, blood pressure, and weight loss, and are highly anticipated as they are also known to have kidney-protective effects recently.

The misconception that 'medication reduces pancreatic function'

There is also a myth that taking diabetes medication reduces pancreatic function, which eventually leads to insulin therapy. Professor Son called this an unfortunate misconception, explaining that at the time of diagnosis, pancreatic beta-cell function is already only about 50%, and in severe cases, only about 20% remains. It is like starting with a mobile phone battery that already has less than one bar left. If exposed to an environment where blood sugar or weight is not continuously controlled for a long time, even that last remaining bar may be lost, necessitating insulin therapy, but he said it is a major misconception to attribute this to drug treatment.

Sulfonylureas were cited as one of the reasons for the misconception. While this medication, which stimulates insulin secretion from pancreatic beta cells, is effective in lowering blood sugar in the early stages, there are stories that long-term use can make the pancreas work continuously and cause it to tire quickly. Professor Son explained that considering the characteristics of some medications as applying to all diabetes medications is an error of overgeneralization. He stated that rather than maintaining sulfonylureas for a very long time, one can reduce concerns by using them for a sufficient short period for patients in a hyperglycemic state or those who respond well, and then sequentially progressing to a combination of treatments—such as SGLT2 inhibitors, GLP-1 drugs, or Metformin, which improve insulin resistance and allow the pancreas to rest—once hyperglycemia is improved.

The medication that receives even greater misconceptions than sulfonylureas is insulin. It is easy to think that if insulin is administered externally, the body will stop producing its own insulin well. However, Professor Son explained that insulin acts as a very powerful blood-glucose-lowering agent, and by improving the hyperglycemic environment, it reduces the burden on beta cells to secrete insulin, thereby playing a role in preserving secretion function in the long term. In the video description, he also emphasized that insulin therapy is not a sign of failure, but a sign of success.