Diabetes Mellitus

Diabetes Mellitus Patient Encounter

A 40-year-old male presents in his physician’s office with complaints of new onset of excessive thirst, urinary frequency and fatigue. His physician ran several tests and based on the results he diagnosed his patient with Type 2 diabetes mellitus. The value of describing patient conditions with ICD-10 codes as compared to ICD-9 codes is made evident when comparing codes available for specific conditions. A common disease affecting millions of patients is diabetes mellitus. According to the American Diabetes Association,

“Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels.”

Coding: ICD-9 to ICD-10

In spite of the significant prevalence of this disease, ICD-9 codes describing this condition lack specificity, resulting in the lumping of many patients into broad categories that are not as useful for comparisons and quality measures as ICD-10 codes will be once implemented. Patients with diabetes mellitus are most often described with two ICD-9 codes. ICD-9 codes in the 250xx series describe primary diabetes of all types. Codes in the 249xx group describe secondary diabetes without information regarding the underlying cause of the diabetes. Each series includes a general description of a few complications that may be associated with this disease without detailed descriptions of those complications. These codes lack the specificity necessary to fully document patients’ medical conditions.

The ICD-10 Index includes approximately six pages of specific listings for diabetes and its various clinical manifestations. Almost all of these listings refer to codes in five separate categories of diabetes mellitus, including E08 (Diabetes due to underlying conditions), E09 (Drug or chemical induced diabetes), E10 (Type 1 diabetes), E11 (Type 2 diabetes), and E13 (Other types of diabetes). Notable exceptions to listings in these five code categories are diabetes in pregnancy, including gestational and pre-existing (O24) and neonatal diabetes mellitus (P70.2).

Within the E08 – E13 code categories, there are approximately 200 specific codes that describe diabetes with various associated manifestations or complications, or about 40 codes in each code category. These specific codes are organized into nine code sections under each of the five diabetes code categories describing diabetes with various complications, including ketoacidosis (Exx.1), kidney complications (Exx.2), ophthalmic complications (Exx.3), neurological complications (Exx.4), circulatory complications (Exx.5), other specified complications (Exx.6), unspecified complications (Exx.8) and diabetes without complications (Exx.9). A single ICD-10 code can therefore be used to describe patients with diabetes and its associated complications, if any. An additional code, (Z79.4), identifies patients treated with insulin to control their diabetes.

eHealth Connection

Use of ICD-10 codes allows clinicians to more accurately describe patients with diabetes mellitus along with associated complications. This information will be essential for participation in future payment systems that base payments on outcomes or those that require risk adjustments to determine appropriate payment levels. Information in ICD-10 codes will be used to determine payments in these future payment systems, making it essential that providers utilize these codes correctly.

Comparison of Current ICD-9 Code and Illustrative ICD-10 Codes