E11

Type 2 diabetes mellitus

## Overview of Type 2 Diabetes Mellitus (E11) Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by hyperglycemia resulting from insulin resistance, a relative lack of insulin secretion, or both. It accounts for approximately 90-95% of all diagnosed cases of diabetes. The condition often progresses gradually, initially with insulin resistance where the body's cells do not respond effectively to insulin. As the disease advances, the pancreas may lose its ability to produce sufficient insulin to overcome this resistance, leading to elevated blood glucose levels. ### Pathophysiology The primary pathological mechanisms involve: * **Insulin Resistance:** Target tissues (muscle, liver, adipose tissue) fail to respond adequately to normal or high levels of insulin, impairing glucose uptake and utilization. * **Beta-Cell Dysfunction:** The pancreatic beta cells, initially hypersecreting insulin to compensate for resistance, eventually become exhausted and lose their capacity to produce enough insulin. * **Increased Hepatic Glucose Production:** The liver inappropriately produces and releases glucose, even in the presence of hyperglycemia. * **Impaired Incretin Effect:** Hormones (like GLP-1 and GIP) secreted by the gut in response to food are less effective, leading to reduced insulin secretion and increased glucagon secretion. ### Diagnosis Diagnosis is typically made based on blood glucose levels. Key diagnostic criteria include: * Fasting Plasma Glucose (FPG) ≥ 126 mg/dL (7.0 mmol/L) * 2-hour Plasma Glucose ≥ 200 mg/dL (11.1 mmol/L) during an Oral Glucose Tolerance Test (OGTT) * Glycated Hemoglobin A1c (HbA1c) ≥ 6.5% * Random Plasma Glucose ≥ 200 mg/dL (11.1 mmol/L) in a patient with classic symptoms of hyperglycemia ### Management Management focuses on achieving and maintaining glycemic control to prevent complications. This typically involves: * **Lifestyle Modifications:** Dietary changes (reduced caloric intake, balanced macronutrients), increased physical activity, and weight loss. * **Pharmacotherapy:** Oral antidiabetic agents (e.g., metformin, sulfonylureas, GLP-1 receptor agonists, SGLT2 inhibitors) and/or injectable insulin. * **Monitoring:** Regular blood glucose monitoring, HbA1c testing, and screening for complications. ### Complications Long-term uncontrolled hyperglycemia can lead to severe microvascular and macrovascular complications, including: * **Microvascular:** Retinopathy (leading to blindness), nephropathy (leading to kidney failure), neuropathy (nerve damage, leading to pain, numbness, and foot ulcers). * **Macrovascular:** Cardiovascular disease (heart attack, stroke), peripheral artery disease. * **Other:** Increased risk of infections, impaired wound healing, and non-alcoholic fatty liver disease (NAFLD).

Clinical Symptoms

  • Increased thirst (polydipsia)
  • Frequent urination (polyuria)
  • Increased hunger (polyphagia)
  • Unintended weight loss
  • Fatigue
  • Blurred vision
  • Slow-healing sores
  • Frequent infections (e.g., skin, urinary tract, vaginal)
  • Numbness or tingling in the hands or feet (neuropathy)

Common Causes

  • Obesity or overweight
  • Physical inactivity
  • Family history of type 2 diabetes
  • Genetic predisposition
  • Age (risk increases with age, especially after 45)
  • Ethnicity (higher prevalence in certain ethnic groups like African Americans, Hispanic/Latino Americans, American Indians, Asian Americans)
  • History of gestational diabetes
  • Polycystic ovary Syndrome (PCOS)
  • High blood pressure (hypertension)
  • High cholesterol or triglycerides
  • Insulin resistance

Documentation & Coding Tips

Always document the control status of Type 2 Diabetes Mellitus (T2DM) and any associated complications. Vague documentation can lead to under-coding of severity and incomplete risk adjustment.

Example: HPI: 62 y.o. male with Type 2 Diabetes Mellitus, *currently poorly controlled* (A1C 9.8%, fasting glucose 185 mg/dL). Reports increased thirst and frequent urination. Patient has *established diabetic peripheral neuropathy* in both feet, causing tingling and numbness, for which he takes gabapentin. He also has *diabetic retinopathy, nonproliferative, mild, affecting both eyes*, stable per recent ophthalmology visit. No active foot ulcers. Medications reviewed and adherent. Assessment: E11.65 (Type 2 diabetes mellitus with hyperglycemia) and E11.42 (Type 2 diabetes mellitus with diabetic polyneuropathy), E11.321 (Type 2 diabetes mellitus with mild nonproliferative diabetic retinopathy with macular edema, unspecified eye). Plan: Adjust insulin glargine dosage, reinforce diet/exercise, check renal function. Patient counseled on increased risk for cardiovascular events due to poorly controlled T2DM and associated comorbidities.

Billing Focus: Documenting 'poorly controlled' or 'uncontrolled' alongside specific complications (e.g., neuropathy, retinopathy, nephropathy) provides critical detail for accurate ICD-10 coding. Specifying laterality (if applicable) and severity of complications (e.g., 'mild nonproliferative') is essential for the highest level of specificity.

When insulin is used for Type 2 Diabetes, clearly document the insulin use and its necessity, distinguishing it from Type 1 Diabetes.

Example: HPI: 55 y.o. female with Type 2 Diabetes Mellitus, *requiring insulin therapy* (currently on insulin detemir 20 units daily) in addition to oral metformin. Patient continues to monitor blood sugars daily (average 160-200 mg/dL). No episodes of DKA or severe hypoglycemia. She has a history of *stage 3 chronic kidney disease due to diabetes* (eGFR 45 mL/min/1.73m^2). Assessment: E11.22 (Type 2 diabetes mellitus with diabetic chronic kidney disease) and Z79.4 (Long-term (current) use of insulin). This patient's T2DM is managed with insulin. Plan: Continue insulin detemir and metformin. Monitor kidney function closely. Refer to nephrology for CKD management.

Billing Focus: Documenting 'requiring insulin therapy' or 'insulin-dependent' for T2DM, along with the Z79.4 code, is crucial for accurate billing. This distinguishes it from Type 1 and accurately reflects the complexity of management. Linkage to specific diabetic complications like CKD is vital for proper E/M level assignment and justifying medical necessity.

Document specific manifestations and complications, linking them directly to the diabetes. Avoid generic terms and always specify 'due to diabetes'.

Example: SUBJECTIVE: Patient reports increasing numbness and tingling in both feet over the past 6 months, consistent with his *known diabetic polyneuropathy*. Denies any foot ulcers or wounds. OBJECTIVE: Neurological exam reveals decreased sensation to light touch and vibratory sense in a stocking-glove distribution, bilateral feet. Monofilament exam abnormal in 3 of 10 sites bilaterally. ROS negative for chest pain, shortness of breath. ASSESSMENT: E11.42 (Type 2 diabetes mellitus with diabetic polyneuropathy). Patient's *hypertension is managed with lisinopril* (I10). *Hyperlipidemia is stable on atorvastatin* (E78.5). Plan: Continue gabapentin, reinforce foot care education, schedule follow-up with podiatry for comprehensive foot exam. Emphasize tight glycemic control to prevent progression of neuropathy.

Billing Focus: Clearly stating 'diabetic polyneuropathy' explicitly links the complication to the diabetes, preventing potential queries for causal relationships. Documenting the specific exam findings (monofilament, sensation) supports the medical necessity of the diagnosis and any related procedures (e.g., diabetic foot care).

Relevant CPT Codes

Related Diagnoses

Hierarchy