** This post was reviewed and updated on January 21, 2024. **
In the world of medical coding, deciphering the relationship between hypertension and chronic kidney disease is crucial. Join us as we explore the connection and navigate the coding guidelines to assign accurate ICD-10-CM codes for the “Name That Code” coding question.
Name That Code
Question: A patient has hypertension, chronic kidney disease, renal failure, and is currently on dialysis. The patient is a former smoker who quit three years ago. Assign the ICD-10-CM codes.
Answer: I12.0, N18.6, Z99.2, Z87.891
Understanding the Link
Before diving into the codes, let’s establish the connection between hypertension and chronic kidney disease. Hypertension, otherwise known as high blood pressure, is a leading cause of chronic kidney disease (CKD). The National Kidney Foundation emphasizes how hypertension can eventually damage the blood vessels, reducing blood supply to the kidneys and other vital organs. Eventually, CKD can lead to kidney failure, also referred to as renal failure, or end-stage renal disease (ESRD), which is the last stage of chronic kidney disease. When the kidneys fail, it means they have stopped working well enough to maintain life without dialysis or a kidney transplant.
Hypertension can also be a complication of CKD, as the kidneys play a significant role in controlling blood pressure. If the diseased kidneys cannot control the blood pressure, the blood pressure increases.
Deciphering the Coding Guidelines
According to the ICD-10-CM Official Guidelines for Coding and Reporting, the coder may assume a causal relationship between hypertension and kidney involvement because the two conditions are linked by the term “with” in the Alphabetic Index. Even if the documentation does not specifically state that the two conditions are related, we can and should code them as related unless the documentation clearly states the conditions are unrelated.
For hypertension and conditions not specifically linked by relational terms such as “with,” “associated with” or “due to” in the classification, provider documentation must link the conditions in order to code them as related.
The coding guidelines also state, “Assign codes from category I12, Hypertensive chronic kidney disease, when both hypertension and a condition classifiable to category N18, Chronic kidney disease (CKD), are present. CKD should not be coded as hypertensive if the provider indicates the CKD is not related to the hypertension. The appropriate code from category N18 should be used as a secondary code with a code from category I12 to identify the stage of chronic kidney disease… If a patient has hypertensive chronic kidney disease and acute renal failure, the acute renal failure should also be coded. Sequence according to the circumstances of the admission/encounter.”
If a patient with CKD also suffers from other serious conditions, such as diabetes mellitus and hypertension, sequencing of the CKD code in relationship to codes for other contributing conditions is based on the coding conventions in the Tabular List.
Locating and Verifying the ICD-10-CM Codes
To assign the correct ICD-10-CM codes for the coding scenario, we must locate and verify the correct codes, considering the relative coding guidelines and conventions.
Hypertension and Chronic Kidney Disease (I12.0)
The documentation uses the word “with” in the documentation to indicate there is a causal relationship between hypertension and CKD. To find the correct code, look in the Alphabetic Index under Hypertension. It instructs the coder to see Hypertension, hypertensive (accelerated) (benign) (essential) (idiopathic) (malignant) systemic)/with/kidney involvement – see Hypertension, kidney. From there, we can go down the list to with/stage 5 chronic kidney disease (CKD) or end-stage renal disease (ESRD) I12.0.
In the Tabular, we can verify this code as:
I12.0, Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end-stage renal disease
A note under I12.0 states, “Use additional code to identify the stage of chronic kidney disease (N18.5, N18.6).”
Also, an Excludes2 note at I10-I1A instructs the coder to assign a code to identify a history of tobacco dependence, which we will discuss more about below.
Chronic Kidney Disease/ESRD (N18.6)
In ICD-10-CM, CKD is classified based on severity, which is designated by stages 1-5:
- N18.1, Chronic kidney disease, stage 1
- N18.2, Chronic kidney disease, stage 2 (mild)
- N18.30 Chronic kidney disease, stage 3 unspecified
- N18.31 Chronic kidney disease, stage 3a
- N18.32 Chronic kidney disease, stage 3b
- N18.4, Chronic kidney disease, stage 4 (severe)
- N18.5, Chronic kidney disease, stage 5
- N18.6, End-stage renal disease (ESRD)
- N18.9, Chronic kidney disease, unspecified
Stage 5 chronic kidney disease and end-stage renal failure are the same thing, even though there are two separate codes for them. Code N18.6 is reported for Stage 5 when dialysis has not been started, and once dialysis has begun, N18.9 is reported.
Per the coding guidelines, “If both a stage of CKD and ESRD are documented, assign code N18.6 only.” Hence, our code here is:
N18.6, End-stage renal disease
A synonym listed under N18.6, End-stage renal disease, is Chronic kidney disease requiring chronic dialysis.
A note at N18 states, “Code First any associated hypertensive chronic kidney disease (I12.-, I13.-).” This tells us that Hypertensive CKD (I12.0) needs to be sequenced first, followed by End-stage renal disease (N18.6).
A “Use additional” note at N18.6 states, “Use additional code to identify dialysis status (Z99.2).”
Renal Dialysis Status (Z99.2)
The documentation indicates the patient is on dialysis, so this code needs to be assigned after N18.6 as:
Z99.2, Dependence on renal dialysis
Other synonyms listed under Z99.2, Dependence on renal dialysis, are:
- Hemodialysis status
- Peritoneal dialysis status
- Presence of arteriovenous shunt for dialysis
- Renal dialysis status NOS
History of Tobacco Dependence (Z87.891)
As mentioned above in the section on coding for Hypertension and CKD (I12.0), the Excludes2 note at I10-I1A instructs us to assign a code to identify the following:
- exposure to environmental tobacco smoke (Z77.22)
- history of tobacco dependence (Z87.891)
- occupational exposure to environmental tobacco smoke (Z57.31)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
The patient is a former smoker, according to the documentation; therefore, we need to assign:
Z87.891, Personal history of nicotine dependence
As medical coders, it’s imperative to grasp the nuances of the coding guidelines and conventions. Always review these guidelines and conventions thoroughly before making final code selections. By understanding the connection between hypertension, chronic kidney disease, and their associated conditions, you should be able to more accurately and comprehensively code for them.
If you would like more coding practice related to hypertension and causal relationships, don’t hesitate to take the coding challenge on hypertension and heart failure here.
Please let me know down below in the Comments section if you found this post helpful and would like more challenges like this in the future.