Understanding Insulin to Treat Diabetes Mellitus

According to various sources on the Internet, the first example of recorded history began 5000 years ago – in approximately 2600 BC. An ailment thought to be diabetes mellitus (DM) was recorded by Egyptians around 1550 BC. It’s easy to see that diabetes has been around for a long, long time. Even ancient Indians were aware of the condition, as they identified diabetes mellitus and diabetes insipidus circa 400-500 BC. They tested for what they called “honey urine” by determining if a urine sample attracted ants. Though early Greek, Indian, Egyptian, Chinese, and Arab physicians knew of the condition, they didn’t understand the cause.

In 1776, Matthew Dobson confirmed that the urine of diabetic patients had a sweet taste. (Don’t want to know how he figured that out!) It wasn’t until the early years of the 20th century before medicine discovered a cause and treatment approach for diabetes. Edward Albert Sharpey-Schafe, an English physiologist who is regarded as the founder of endocrinology, determined that diabetes was the result of the pancreas being unable to produced what he named “insulin.” The best treatment physicians could offer diabetics at the time was a fasting diet and regular exercise.

In 1921, Canadian researcher Sir Frederic Banting, along with Charles Best, proved that insulin removed from the pancreases of healthy dogs could be used to treat diabetic dogs. Thus, a treatment was discovered for diabetic humans and was first used to treat a human patient the following year.

As successful as insulin was in treating DM, not all patients responded to it. It wasn’t until 1936 that British Scientist Harold Himsworth finally distinguished between what is now known as Type 1 and Type 2 diabetes. Type 1 DM prevents the pancreas from producing any insulin. Type 2 is typified by insulin resistance, meaning the body has lost its sensitivity to insulin and cannot utilize insulin properly. The pancreas responds by increasing insulin output, putting stress on the organ over time, resulting in pancreatic damage.

Fast forwarding to today, there are a number of different types of insulin used to treat Type 1 DM as well as insulin-requiring Type 2 DM. (See Chart A for more specific information.) The types include:

  • Rapid-acting
  • Regular- or short-acting
  • Intermediate-acting
  • Long-acting
  • Pre-mixed


Insulin can be administered in several different fashions.

  • Most often its self-administered via syringe, unless the patient is physical incapable of doing so. Syringe size is determined by the insulin dose. Needle sizes vary and patient preference plays a role in the size selected. Shorter needles usually mean less sting on injection.
  • Insulin pens come prefilled with multi-doses of the medication.
  • Computerized/motorized Insulin pumps are attached to a thin tube implanted under the skin; some models also act as a glucose monitor.
  • Jet injection devices hold several doses of insulin; held against the skin, push a button, and insulin is pushed through.
  • Inhaled insulin comes in an inhaler, kind of like a respiratory inhaler.

Insulin dosing is based on blood glucose levels. Unless the patient has a continuous glucose monitor (either combined with insulin pump or as a separate device), glucose is checked via finger-stick monitors. Using too much or too little insulin can cause a variety of diabetic-related disorders such as diabetic ketoacidosis.

Insulin used to control DM is addressed in the ICD-10-CM OGCR Guideline 4.a.3. If/when long term (current) use of insulin is documented in the chart, no matter the type of DM (1 or 2), the coder should assign Z79.4

Though sometimes managed with insulin, most Type 2 diabetes are managed through oral hypoglycemic and/or non-insulin injectable medications, which will be covered in a future blog.









Within a few minutes

Several hours

Covers insulin needs for meals eaten at same time as injection. Often used with long-acting insulin.

Regular- or Short-acting

Approximately 30 minutes

3 – 6 hours

Provides coverage for meals eaten within 30-60 minutes.


2 – 4 hours

Can last up to 18 hours

Covers insulin needs for about half the day or overnight; often combined with a rapid- or short-acting insulin.



Can work for entire day

Meets insulin needs for about one full day; can be combined, when needed, with rapid- or short-acting insulin.

Pre-mixed (a combination of specific amounts of intermediate- and short-acting insulin in one bottle or insulin pen)


Depending on percentage of intermediate- and short-acting insulin, duration can be between 14 – 24 hours

Pre-mixed insulins generally taken 2 – 3 times a day before mealtime




Ancient physicians recognized diabetes mellitus as a disease thousands of years ago, though they use the term until far later. It wasn’t until the 1920s that insulin was first discovered and used to treat diabetes. Today, there are many different types of insulin that can be used to treat this disease.






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