Q&A: When documentation drives diabetes coding

Q: How does documentation specificity affect diabetes code assignment?

A: The details included in a medical record can significantly affect code assignments. The following three examples show how documentation specificity, relationships between conditions, and medication use can influence diabetes coding.

First, consider a 63-year-old female who presents with diabetic stage 3a chronic kidney disease. Her A1C is 6.1, and she needs a refill for metformin. The chronic kidney disease is stable per the nephrologist, and she will continue to avoid nonsteroidal anti-inflammatory drugs. In this case, the provider has already documented a relationship between diabetes and chronic kidney disease. That documentation supports the assignment of ICD-10-CM code E11.22 (type 2 diabetes mellitus with diabetic chronic kidney disease). Additional codes include N18.31 (chronic kidney disease, stage 3a) and Z79.84 (long-term [current] use of oral hypoglycemic drugs). This example demonstrates the importance of identifying and coding both the diabetes and its documented complication, as well as capturing applicable long-term medication use.

Next, consider a 42-year-old diabetic male who has been following his diet guidelines and has not gained additional weight since his last visit. His metformin prescription is refilled, and he is advised to follow his current routine. In this example, the medical record does not specify the type of diabetes. According to ICD-10-CM guidelines, when the type of diabetes is not documented, the default is type 2 diabetes. The documentation also indicates that the patient is doing well with his diet, which is an important component of diabetes management. Because of this note and the fact that no complications are documented, the appropriate codes assigned would be E11.9 (type 2 diabetes mellitus without complications) and Z79.84 (long-term [current] use of oral hypoglycemic drugs). This example highlights how the absence of documented complications can be just as important as the presence of documented complications when determining the appropriate level of coding specificity.

Lastly, consider a 57-year-old female with diet-controlled type 2 diabetes and hyperlipidemia that has improved over the past month due to regular medication use. The provider refills atorvastatin and metformin and instructs her to follow up in three months. The key point in this example is that the provider has documented a relationship between the hyperlipidemia and diabetes. Lipid abnormalities are commonly associated with diabetes, particularly type 2 diabetes. Although lipid abnormalities may improve with better glycemic control, normalization does not usually occur because of the strong relationship between vascular disease and hyperlipidemia in patients with type 2 diabetes. This relationship documented by the provider provides the support needed for the diabetes-with-complication code. As a result, the appropriate codes are E11.69 (type 2 diabetes mellitus with other specified complication), E78.5 (hyperlipidemia, unspecified), and Z79.84 (long-term [current] use of oral hypoglycemic drugs).

Together, these examples emphasize the importance of specificity in diabetes documentation. Proper coding ultimately begins with accurate documentation, and it is the coder's responsibility to assign codes to the highest level of specificity supported by the medical record. This includes selecting the correct diabetes code, identifying and coding any documented complications, determining whether those complications are related to diabetes, and capturing long-term medication use when applicable. In some cases, there are certain conditions for which a cause-and-effect relationship with diabetes can be assumed under coding guidelines; however, not every condition can automatically be considered related to diabetes. When a provider specifically links a condition to diabetes, that documentation can provide crucial support for accurate code assignment.

As these examples demonstrate, multiple codes may be necessary to fully capture the patient’s clinical picture and accurately reflect the care documented in the medical record.

Editor’s note: This Q&A originally appeared in JustCoding. This question and answer were adapted from the HCPro webinar, “Diabetes Coding Made Clear: Capturing the Complication,” presented by Yelena Smirnykh, CPC-I, CPC, CDEO, CCDS-O, CMRS, CPB.