Insulin Therapy Guidelines: Applicable Population and Early Intervention

Which diabetic patients are suitable for insulin? Insulin is an essential hormone secreted by pancreatic beta cells. Not all diabetic patients need insulin, but some require exogenous insulin therapy.

① Type 1 diabetes: These patients are dependent on insulin for life once diagnosed; without it, their lives are at risk.

② Type 2 diabetes: When blood sugar is poorly controlled despite high-dose oral medications, insulin is needed to control blood sugar.

③ Diabetic patients during pregnancy or with gestational diabetes.

④ When serious acute complications occur, such as ketoacidosis or hyperosmolar coma.

⑤ Diabetic patients with severe infections.

⑥ Diabetic patients requiring medium or major surgery due to other diseases.

⑦ Diabetic patients with serious chronic complications, such as severe nephropathy, neuropathy, or retinal hemorrhage.

What adverse reactions can insulin cause?

① Hypoglycemia: Mostly caused by excessive insulin use, insufficient food intake after pre-meal injection, or excessive physical activity. Therefore, blood glucose should be monitored frequently.

② Insulin leakage: Although uncommon, some patients experience a small amount of insulin leaking from the injection site upon needle removal. This can lead to inaccurate insulin dosage. Therefore, it is crucial to use the correct injection technique: pinch the skin tag, insert the needle at a 45-degree angle, inject slowly, and immediately press the injection site with a cotton ball after injection.

③ Fat pads: Caused by long-term insulin injection at the same site, stimulating subcutaneous fat hyperplasia. Injecting insulin at fat pad sites will affect drug absorption; injection sites should be changed regularly.

④ Subcutaneous fat atrophy: Long-term injection at the same site can lead to subcutaneous fat atrophy or fibrous hyperplasia, forming small, barely noticeable indentations. Prevention involves rotating injection sites. ⑤ Insulin Allergy: Local allergic reactions may manifest as flushing or fever at the injection site, or isolated wheals, usually appearing 30 minutes after injection. Delayed reactions may occur 4-12 hours later, presenting as skin redness, swelling, itching, and induration. Systemic allergic reactions may manifest as urticaria, angioedema, purpura, and in rare cases, anaphylactic shock. Allergic reactions are more common with animal insulin than with recombinant human insulin. Allergic reactions can occur upon initial use, after one month of use, or after a period of discontinuation followed by re-use.

⑥ Skin Infection: Often caused by poor skin hygiene. Attention should be paid to skin hygiene and aseptic technique during injection.

⑦ Insulin Edema: Before diabetes is controlled, there is dehydration, sodium loss, and a decrease in extracellular fluid. Once insulin treatment is initiated and blood sugar is controlled, water and sodium retention occurs within 4-6 days, resulting in facial and limb edema. This usually resolves spontaneously within a few days. ⑧ Refractive error: Rapidly decreasing blood glucose after insulin administration affects the osmotic pressure of the lens and vitreous humor, causing water to escape from the lens and reducing refractive power, resulting in farsightedness and blurred vision. This is only a temporary phenomenon and usually resolves spontaneously within 2-4 weeks.

⑨ Hyperinsulinemia: Especially common in type 2 diabetes patients with obesity, and often in those using excessive insulin dosages.

⑩ Weight gain: Especially common in elderly type 2 diabetes patients. Abdominal obesity after insulin injection is a manifestation of hyperinsulinemia. Purified insulin can be used instead, or biguanides or alpha-glucosidase inhibitors can be added to reduce the insulin dosage.

Why is early insulin therapy recommended for type 2 diabetes patients? In recent years, the concept of using insulin in the early stages of type 2 diabetes has gradually gained acceptance. Early use of insulin is a more effective way to maintain normal blood glucose levels. Early means using insulin as the first-line drug, or starting after the first oral medication has become ineffective. Traditional type 2 diabetes treatment follows a step-by-step approach. The traditional stepwise approach to diabetes involves lifestyle changes (such as increased exercise and dietary adjustments), progressing from one or more oral hypoglycemic agents to insulin replacement therapy when blood glucose levels fail to reach target levels, and finally to intensive insulin therapy. This approach often results in prolonged periods of uncontrolled glycated albumin (HbA1c) and chronic hyperglycemia, leading to near-complete loss of pancreatic beta cell function by the time insulin is used. In contrast, early intensive insulin therapy can provide long-term, effective blood glucose control and improve beta cell function.

The advantages of early insulin use are summarized below:

① Protects and improves pancreatic secretory function, eliminates "glucose toxicity" and "lipotoxicity," reduces the burden on pancreatic beta cells, and slows beta cell depletion and the natural progression of diabetes. It can also restore drug sensitivity in patients who have experienced secondary failure of oral hypoglycemic agents.

② Improves insulin resistance.

③ Restores first-phase insulin secretion. In the early stages of diabetes, beta cell function damage is irreversible. Strict early blood glucose control can improve insulin secretion function and restore first-phase insulin secretion.

④ Reduces the occurrence and development of cardiovascular complications. Because insulin administration promotes normal glucose and lipid metabolism, alters insulin resistance, and has a protective effect on the cardiovascular system.

What is insulin replacement therapy? Strictly speaking, insulin is not a drug, but a normal physiological hormone secreted by pancreatic islet cells to regulate blood sugar. When the body's insulin levels are absolutely or relatively insufficient, exogenous insulin can be injected to supplement it; this is medically termed replacement therapy. Insulin replacement therapy can significantly improve the quality of life for diabetic patients. All type 1 diabetic patients, because their pancreatic islet cells have failed to produce insulin to regulate blood sugar, require lifelong insulin replacement therapy; otherwise, they cannot sustain life. This is what insulin replacement therapy refers to. Some type 2 diabetic patients, especially those who have failed long-term oral hypoglycemic agents, or those with diabetes during stress, surgery, or pregnancy, are often given supplemental insulin by doctors to alleviate their condition as quickly as possible. In severe cases, long-term, high-dose insulin use is required to achieve therapeutic goals; this treatment is called insulin replacement therapy. Insulin therapy is a supplement and repair of physiological deficiencies, necessary for maintaining health. Clinically, it is often observed that after 2-3 months of intensive insulin therapy, patients' pancreatic function gradually recovers, insulin dosage is gradually reduced, and blood glucose levels can return to normal or near-normal levels. At this point, oral hypoglycemic agents can be used for treatment. However, some patients require long-term insulin replacement therapy due to pancreatic islet dysfunction.