August 7, 2006

Coding for Chronic Kidney Disease
For The Record
Vol. 18 No. 16 P. 57

Effective October 1, 2005, ICD-9-CM category 585 was expanded to the fourth-digit subcategory level as follows:

• 585.1, Chronic kidney disease (CKD), Stage I;

• 585.2, CKD, Stage II (mild);

• 585.3, CKD, Stage III (moderate);

• 585.4, CKD, Stage IV (severe);

• 585.5, CKD, Stage V;

• 585.6, End-stage renal disease (ESRD); and

• 585.9, CKD, unspecified (includes chronic renal disease, chronic renal failure not otherwise specified, and chronic renal insufficiency).

Note: Acute renal insufficiency remains classified to code 593.9.

In addition, the code title was revised for category 585 from chronic renal failure to CKD, which is defined according to the presence or absence of kidney damage and the level of kidney function. The stages are defined based on the glomerular filtration rate (GFR) as shown in Table 1. The GFR is calculated from the results of the patient’s blood creatinine test, age, race, gender, and other factors and is the best test to measure the level of kidney function.

Code assignment will be based on physician documentation of the specific stage and not the GFR. In addition, if a specific CKD stage and ESRD are documented, only code 585.6 is assigned (AHA Coding Clinic for ICD-9-CM, 2006, first quarter, page 53).

Signs and Symptoms
Common signs and symptoms of CKD include the following:

• fatigue;

• trouble concentrating;

• poor appetite;

• trouble sleeping;

• nighttime muscle cramping;

• swollen feet and ankles;

• puffiness around the eyes, especially in the morning;

• dry, itchy skin; and

• increase in urination, especially at night.

CKD and Hypertension
Even though category 585 was revised and expanded, coders should still assume a cause-and-effect link between the hypertension and CKD. The following coding note remains in ICD-9-CM under category 403, “Any condition classifiable to 585, 586, or 587 with any condition classifiable to 401.” Also, an excludes note is located under category 585 which states, “that with any condition classifiable to 401 (403.0-403.9 with fifth-digit 1).”

In addition, the following note has been added to category 403: “Use additional code to identify the stage of the chronic kidney disease (585.1-585.6), if known.” Therefore, if the physician documents ESRD and hypertension, assign codes 403.91 and 585.6. No cause and effect link is needed. If the physician documents chronic renal failure and hypertension, assign only code 403.91. Chronic renal failure now goes to 585.9. Since that is not included in the code range under the new coding directive under category 403, only one code is needed.

As noted above, chronic renal insufficiency is now classified to code 585.9. Previous AHA Coding Clinic for ICD-9-CM advice has stated that ICD-9-CM assumes a link between renal failure (not insufficiency) and hypertension. Although it states renal failure with hypertension, it also states categories classified to 585-587 (AHA Coding Clinic for ICD-9-CM, 1990, third quarter, page 3). The updated ICD-9-CM Official Guidelines for Coding and Reporting effective December 1, 2005, states, “Assign codes from category 403, Hypertensive kidney disease, when conditions classified to categories 585-587 are present. Unlike hypertension with heart disease, ICD-9-CM presumes a cause-and-effect relationship and classifies renal failure with hypertension as hypertensive kidney disease” (AHA Coding Clinic for ICD-9-CM, 2006, first quarter, pages 47-48).

In addition, AHA Coding Clinic for ICD-9-CM also states that the coding conventions in ICD-9-CM take precedence over the official coding guidelines (AHA Coding Clinic for ICD-9-CM, 2006, first quarter, page 99). Therefore, based on the coding directives located in ICD-9-CM, coders can assume the link between chronic renal insufficiency (which is now under the CKD category) and hypertension. The directives all state CKD with hypertension—and chronic renal insufficiency—is now classified as CKD. This advice may change in the future as coding guidelines, AHA Coding Clinic for ICD-9-CM advice, and coding directives are updated.

Coding and sequencing for CKD are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to nearly 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payors as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.

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