According to the Centers for Disease Control and Prevention (CDC), 37 million adults in the US have chronic kidney disease (CKD) and most of them are unaware of their condition. Accurately documenting and staging CKD can capture our members’ appropriate health status.
Best practices when documenting CKD:

• Underlying cause: Diabetes or hypertension. If unrelated to diabetes or hypertension, the cause should be documented, if known.
• Associated diagnosis: ICD-10-CM guidelines state that CKD can be assumed “due to” both hypertension and diabetes, even in the absence of the provider linking them, unless the provider clearly states the conditions are unrelated or links to another condition.
• Stage of CKD: CKD is divided into stages based on estimated glomerular filtration rate (eGFR) test results. Below is a chart with the corresponding CKD stage:

Avoid using unspecified diagnosis codes (N18.30 and N18.9) if more information from a provider is documented to determine the level of specificity.

• CKD severity: If documentation includes CKD severity using mild, moderate or severe instead of a stage, the corresponding stage may be assigned using the information below:

  • Mild – stage 2
  • Moderate – stage 3
  • Severe – stage 4
• Dialysis dependence: Dependence on renal dialysis (Z99.2) should be documented if applicable, along with the frequency of dialysis active treatment visits. It includes peritoneal dialysis, hemodialysis, presence of arteriovenous shunt or fistula for dialysis, renal dialysis status.

• Coders cannot assume the CKD stage based on the eGFR report and medication list. The stage/severity must be clearly documented by the provider within the medical record to identify the appropriate stage of CKD.
• If the documentation states both CKD and ESRD, report only N18.6, End-stage renal disease. An additional code should be reported to identify dialysis status.
• Acute renal failure (ARF) and CKD are different conditions and are not interchangeable. CKD develops over time whereas ARF has a rapid onset. For a patient with both ARF and CKD, both should be coded.

Example 1. A type 2 diabetic with known stage 3a CKD presents to his physician’s office for a six-month follow-up visit.

Correct codes:

• E11.22 (Type 2 diabetes mellitus with diabetic chronic kidney disease)
• N18.31 (Chronic kidney disease, stage 3a)

Rationale: ICD-10-CM presumes a causal relationship between diabetes and CKD. These conditions should be coded as related, even in the absence of provider documentation explicitly linking them, unless the documentation clearly states the conditions are unrelated and due to some other underlying cause besides diabetes.

Example 2. A patient with severe CKD and chronic combined systolic and diastolic heart failure, comes for a medication refill.

Correct codes:

• I13.0 (Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease)
• I50.42 (Chronic combined systolic (congestive) and diastolic (congestive) heart failure)
• N18.4 (Chronic kidney disease, stage 4 (severe))

Rationale: ICD-10-CM presumes a causal relationship between hypertensive heart disease and CKD, unless CKD is linked by a provider to another condition. If a provider documents the severity of CKD instead of the stage, the corresponding stage code can be used.

Example 3. 75-year-old male has ESRD and is going dialysis three times a week with no complications currently. His hypertension is well controlled on lisinopril.

Correct codes:

• I12.0 (Hypertensive chronic kidney disease with stage 5 chronic kidney disease or ESRD)
• N18.6 (ESRD)
• Z99.2 (Dependence on renal dialysis)

Rationale: ICD-10-CM presumes a causal relationship between hypertension and kidney involvement unless provider specifically indicates both conditions are not related.

Example 4. 70-year-old male with hypertension needs a refill for losartan. He also has moderate CKD due to polycystic kidney disease.

Correct codes:

• I10 (Essential (primary) hypertension)
• N18.30 (Chronic kidney disease, stage 3 unspecified)
• Q61.2 (Polycystic kidney, adult type)

Rationale: The provider has clearly documented that CKD is due to polycystic kidney disease. Therefore, a cause-and-effect relationship between hypertension and CKD cannot be assumed. Provider has documented moderate severity for CKD which corresponds to unspecified stage 3 ICD-10 code.