ICD-9-CM vs. ICD-10-CM: Examine the differences in diabetes coding
The physician documents diabetes mellitus in the patient’s medical record. What is the ICD-9-CM code?
Most coders can quickly come up with 250.00. And if the physician only documented diabetes mellitus, that’s the correct ICD-9-CM code. If a physician doesn’t document complications or type of diabetes, coders default to code 250.00 (diabetes mellitus without mention of complications), says Jill Young, CPC, CEDC, CIMC, president of Young Medical Consulting, LLC, in East Lansing, MI. However, 250.00 is not necessarily the best code to describe the patient’s actual condition.
Consider these two patients. Patient A is a type 2 diabetic with well controlled diabetes. Patient B is a type 2 diabetic with uncontrolled diabetes who also suffers from diabetes-related chronic kidney disease.
If the physician documents “diabetes mellitus” for both patients, coders would report the same code, even though the patients have very different conditions. The physician loses reimbursement on Patient B, who is sicker and requires more care, Young says.
Coding in ICD-9-CM
When it comes to the code assignment for diabetes mellitus in ICD-9-CM (250 code series), coders identify whether the diabetes is type 1or 2 using a fifth digit, says Shannon E. McCall, RHIA, CCS, CCS-P, CPC, CPC-I, CEMC, CCDS, director of HIM/coding for HCPro, Inc., in Danvers, Mass, and an AHIMA-approved ICD-10-CM/PCS trainer. If the diabetes is secondary, coders choose from codes in the 249 series.
Under series 250, coders will find 10 different subcategories that further define and refine the patient’s actual condition.
- 250.0, diabetes mellitus without mention of complication
- 250.1, diabetes with ketoacidosis
- 250.2, diabetes with hyperosmolarity
- 250.3, diabetes with other coma
- 250.4, diabetes with renal manifestations
- 250.5, diabetes with ophthalmic manifestations
- 250.6, diabetes with neurological manifestations
- 250.7, diabetes with peripheral circulatory disorders
- 250.8, diabetes with other specified manifestations
- 250.9, diabetes with unspecified complication
All of those codes require a fifth digit to indicate whether the diabetes is controlled or uncontrolled, type 1or type 2. The fifth digit subclassifications are:
- 0 for type 2 or unspecified type, not stated as uncontrolled
- 1 for type1I, [juvenile type], not stated as uncontrolled
- 2 for type 2 or unspecified type, uncontrolled
- 3 for type 1, [juvenile type], uncontrolled
Coders also need to note that codes 250.4, 250.5, 250.6, 250.7, and 250.8 all include instructions to use an additional code to identify manifestations as diabetic. For example, if the physician documents type 2 diabetic with uncontrolled diabetes with moderate diabetes-related chronic kidney disease, coders would report two codes:
- 250.42, diabetes with renal manifestations, uncontrolled
- 585.3, chronic kidney disease, Stage III (moderate)
Those two codes provide a much clearer picture of the patient’s actual health.
Coders also would add V58.67to identify long-term insulin use if the physician documented it.
Coding in ICD-10-CM
ICD-10-CM provides coders with a much greater range of codes to choose from in the E08–E13 (Diabetes mellitus) series. As a result, providers must document additional information, such as any underlying condition that caused the diabetes or whether drugs induced the diabetes. When physicians don’t sufficiently document the information, coders end up guessing, says Susan Fenton, PhD, RHIA, assistant professor of health information management (HIM) at Texas State University in San Marco.
In ICD-10-CM, the categories of diabetes mellitus will help identify the type of diabetes, says McCall. Those categories are:
- E08, diabetes mellitus due to underlying condition
- E09, drug or chemical induced diabetes mellitus
- E10, type 1 diabetes mellitus
- E11, type 2 diabetes mellitus
- E13, other specified diabetes mellitus
ICD-10-CM further divides secondary diabetes into several different types, McCall says. For example, a patient may have diabetes due to a condition or a drug the patient is taking.
When it comes to type 1 and 2 diabetes, instead of falling under one category in ICD-9-CM (250), each type has its own category in ICD-10-CM, which is a nice enhancement, McCall says.
In ICD-10-CM, complications and manifestations will still be identified in the code series, McCall says. Coders are already used to this with ICD-9-CM coding. In ICD-9-CM, the fourth character identifies manifestations and complications.
Diabetes codes in ICD-10-CM can have up to six characters. The first three characters represent the category, just as they do in ICD-9-CM. The fourth character identifies the presence of manifestations or complications. The fifth and sixth characters identify specific types of manifestation.
ICD-10-CM codes for diabetes are combination codes that include the etiology and the manifestations, McCall says.
Consider the patient who has type 2 uncontrolled diabetes with moderate diabetes-related chronic kidney disease. A note under the code for type 2 diabetes mellitus with diabetic chronic kidney disease instructs coders to use an additional code to identify the stage of chronic kidney disease (N18.1–N18.6). So coders will need two codes in ICD-10-CM, just as they do in ICD-9-CM.
In ICD-10-CM, coders would report:
- E11.22, type 2 diabetes mellitus with diabetic chronic kidney disease
- N18.3, chronic kidney disease, stage 3 (moderate)
If the physician documents long-term insulin use, as well, coders would report Z79.4.
Documenting diabetes in ICD-10-CM
Diabetes documentation and coding will need to include:
- Type or cause of diabetes
- Type 1
- Type 2
- Due to drugs or chemicals
- Due to underlying condition
- Other specified diabetes
- Body system complications related to diabetes, such as kidney or neurological complications
- Specific complications, such as:
- Chronic kidney disease
- Foot ulcer
- Hypoglycemia without coma
Currently, when a coder queries a physician about a patient's diabetes, the coder is probably using a preformatted query geared toward documentation requirements for ICD-9-CM, says Donna Smith, RHIT, AHIMA-approved ICD-10 trainer and senior consultant for 3M Health Information Systems. She recommends changing the query forms now to get physicians used to the additional information they will need to document for ICD-10-CM.
For secondary diabetes, the documentation of the specific type of secondary diabetes will be increasingly important so that coders assign the correct category of codes, McCall says.
Differences between ICD-9-CM and ICD-10-CM
One striking difference in coding for diabetes in ICD-10-CM centers on the concept of controlled or uncontrolled diabetes, McCall says. In ICD-9-CM, coders need that information in order to select the appropriate fifth digit. However, if coders reference diabetes mellitus in the ICD-10-CM alphabetic index, they will find that the concept of controlled or uncontrolled is coded in a different way.
If coders look up the terms they commonly use, such as inadequately controlled, poorly controlled, or out of control, they will find an instruction telling them to code to the type of diabetes—type I, type 2, due to an underlying condition, due to a drug—with hyperglycemia. “That’s how we’re going to report diabetes that is not considered controlled,” McCall says.
Oddly, though, ICD-10-CM does not include uncontrolled as a modifying term, even though that is what coders have badgered physicians to report for years, she adds. “I think it would be fair to say it would be the same guidance as these other synonymous terms that it would be coded to the type of diabetes with hyperglycemia.”
When it comes to secondary diabetes in ICD-10-CM due to a drug or chemical, coders will find an instruction to “code first (T36–T65) to identify drug or chemical.” Coders will find the T codes in the table of drugs and chemicals, McCall says. Coders need to code the T code first, then the diabetes code.
For example, a physician documents an initial encounter with a patient who has corticosteroid-induced diabetes mellitus without complications. In ICD-10-CM, coders would report:
- T38.0x5A, adverse effect of glucocorticoids and synthetic analogues, initial encounter
- E09.9, drug or chemical induced diabetes mellitus without complications
The diabetes is coded as an adverse effect of a corticosteroid, McCall says. This could have some impact for inpatient coders. Traditionally when a patient is admitted for secondary diabetes, coders report the secondary diabetes code first, as the principle reason for the admission. The ICD-10-CM guidelines to code the drug or chemical first could affect MS-DRG selection, McCall says.
When it comes to looking at the guidelines, coders need to be aware of an instructional note that McCall sees as somewhat contradictory. The ICD-10-CM guidelines instruct coders to report first for the T code for use of steroids when patients are taking appropriately but suffer an adverse event.
The 2012 Official Coding Guidelines for ICD-10-CM added the guideline:
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug (T36–T50).
That seems to contradict the guideline to code the T code first instead of the diabetes code, McCall says. “I think this is one instance where there is going to have to be some additional clarification made so coders sequence these codes correctly.”
ICD-10-CM coding example
A physician diagnoses a patient with severe nonproliferative diabetic retinopathy with macular edema due to insulin-dependent type 2 diabetes mellitus.
Although this example may look like coders will need several codes, in ICD-10-CM, they actually need only one code to identify the diabetes and the manifestation of severe nonproliferative diabetic retinopathy, McCall says.
For this scenario, coders would report:
- E11.341, type 2 diabetes mellitus with severe nonproliferative diabetic retinopathy with macular edema
- Z79.4, long-term use of insulin
“I think there are some great advancements with being able to give a full picture of the diabetes and the related manifestation,” McCall says. “I think the addition of the severity is also a good addition to show how ill the patients really are.”
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