The Facts Surrounding the Coding Chronic Kidney Disease

Complications of CKD include early death and heart disease.

Chronic kidney disease (CKD) affects 15 percent of United States adults, or 37 million people, according to a recent statement by the Centers for Disease Control and Prevention (CDC).  The following are some basic facts about CKD; specifically, it is:

1. More common in people 65 and older than other adult groups
2. More common in women
3. More common in black people than other ethnicities

The risk factors for CKD include diabetes, hypertension, heart disease, obesity, family history of CKD, prior history of kidney damage, and older age. Diabetes and hypertension are the major risk factors for CKD.

CKD damages the kidneys over time so the kidneys can no longer clean the blood as they should. The result is that the wastes and extra water accumulates in the body, and other health problems occur. CKD has five stages, including end stage renal disease (ESRD). The complications of CKD include early death, heart disease, stroke, anemia, low blood calcium, high potassium, loss of appetite, extra fluid in the body, infections, and depression. The CDC recommends the following habits to prevent CKD:

1. Control hypertension
2. Control high blood sugar levels
3. Maintain a healthy body weight
4. Eat a balanced diet
5. Participate in physical activity

The coding for CKD begins at category N18, which captures the stages. N18.1-N18.5 are used to specify CKD stage 1 through stage 5. N18.6 is coded for ESRD. N18.9 is the ICD-10-CM code for unspecified CKD.  This code would be a focus of clinical documentation improvement, as stages 4 and 5 are complication/comorbidity (CC) diagnoses, and ESRD is a major complication/comorbidity (MCC). From the Hierarchical Condition Category (HCC) perspective: N18.3 (stage 3) N18.6 (ESRD) codes are HCCs, so the stage will impact the HCC status.

CKD with hypertension is coded based on the CKD stage as well. I12.0 with N18.5/N18.6 is the combination of CKD and hypertension with the second code indicating ESRD or CKD stage 5. I12.9 with N18.1-N18.4 or N18.9 is hypertension with CKD stages 1-4 or unspecified. CKD with chronic heart disease and hypertension is classified with a combination of codes. I13.0 is hypertension with heart failure and CKD stages 1-4 or unspecified. I13.10 is hypertension without heart failure and CKD stages 1-4 or unspecified. I13.11 is hypertension without heart failure and CKD stages 5, or ESRD. I13.2 is hypertension with heart failure and CKD stage 5 or ESRD. Additional codes are assigned for the specific CKD stage and I50.- for heart failure, if present. 

Complications of kidney transplant, which can be a treatment for CKD, are found in the subcategory of T86.1. Please note the instructional notes at the category level. If a patient has a history of a kidney transplant, then assign Z94.0. While most transplant statuses are HCCs, Z94.0 is only an Rx-HCC, not a CMS-HCC. Z94.0 is important as it is a CC for inpatients.

Clinical documentation specialists, inpatient coders, and risk adjustment coders should be very acquainted with the CKD codes as well as the condition’s clinical aspects. These diagnosis codes impact MS-DRGs and HCCs. The skills of clinical documentation specialists and coders are required to achieve highest appropriate reimbursement.

Resources:

Centers for Medicare & Medicaid Services (CMS) Mid-Year 2019 HCC Mappings, https://www.cms.gov/Medicare/Health-Plans/MedicareAdvtgSpecRateStats/Risk-Adjustors.html?DLSort=0&DLEntries=10&DLPage=1&DLSortDir=descending

Centers for Medicare and Medicaid Services (CMS) v36 Table J (Complete List of CCs) and Table I (Complete List of MCCs).   https://www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/AcuteInpatientPPS/FY2019-IPPS-Final-Rule-Home-Page-Items/FY2019-IPPS-Final-Rule-Tables.html?DLPage=1&DLEntries=10&DLSort=0&DLSortDir=ascending

Centers for Disease Control and Prevention: https://www.cdc.gov/kidneydisease/index.html