How Do I Code Diabetes With Chronic Kidney Disease?

Section I.C.4.a describes what the diabetes codes are: “The diabetes mellitus codes are combination codes that include the type of diabetes mellitus, the body system affected, and the complications affecting that body system. As many codes within a particular category as are necessary to describe all of the complications of the disease may be used. They should be sequenced based on the reason for a particular encounter.” E11.22 is one of those combination codes — type 2, kidney, CKD.

The combination code does not carry the stage, so the tabular asks for it: E11.22 carries “Use additional code to identify stage of chronic kidney disease (N18.1-N18.6),” and category N18 answers from the other end with “Code first any associated: diabetic chronic kidney disease (E08.22, E09.22, E10.22, E11.22, E13.22) | hypertensive chronic kidney disease (I12.-, I13.-).” The pair is written at both codes, the way the Code First / Use Additional Code convention always is.

The link between the diabetes and the CKD is the “with” convention. The Index entry “Diabetes, diabetic › type 2 › with › chronic kidney disease” gives E11.22 directly, and Section I.A.15 says conditions listed under “with” in the Index are presumed related “unless the documentation clearly states the conditions are unrelated.” The provider does not have to write “due to diabetes”; the provider would have to write that it is not. Section I.C.14.a.3 confirms the sequencing question is settled by the tabular: “The sequencing of the CKD code in relationship to codes for other contributing conditions is based on the conventions in the Tabular List.”

1. Confirm both diagnoses are documented — diabetes (with its type, if stated) and chronic kidney disease with a stage. Type not documented defaults to type 2 (E11.-) per I.C.4.a.2; insulin use alone does not make it type 1 (I.C.4.a.3).
2. Take the Index route: Diabetes › [type] › with › chronic kidney disease. Type 2 gives E11.22; type 1 E10.22; due to an underlying condition E08.22; drug-induced E09.22; other specified E13.22.
3. Verify in the Tabular and read E11.22’s Use Additional Code note: the N18 stage code follows.
4. Pick the stage from the documentation (I.C.14.a.1): stage 1 N18.1, stage 2 N18.2, stage 3 N18.30/N18.31/N18.32 (3a and 3b are distinct codes), stage 4 N18.4, stage 5 N18.5, ESRD N18.6. “If both a stage of CKD and ESRD are documented, assign code N18.6 only.” N18.6 asks for Z99.2 if the patient is on dialysis.
5. Check for hypertension. If it is also documented, I.C.9.a.2 assigns category I12 (or I13 when heart disease is present too), with N18 as the secondary code; the diabetes code and the hypertension code both sit above the single N18 code, as N18’s Code First note lists both.
6. Add the control agent from Z79 — Z79.4 insulin, Z79.84 oral hypoglycemics, Z79.85 injectable non-insulin — following the E11 category note and I.C.4.a.3, including both when both are used. Not Z79.4 for insulin given temporarily during the encounter.
7. Sequence by the reason for the encounter (I.C.4.a) — the diabetes code leads when the diabetes is why the patient is seen; the N18 code never precedes it.

1. Type 2 diabetes with CKD stage 3a, on metformin; seen for diabetes management.E11.22 → N18.31 → Z79.84. The “with” subterm presumes the relationship; the stage is a separate code; the oral agent is the Z79 code the category asks for.
2. Type 2 diabetes, hypertension, and CKD stage 4; both conditions documented, neither stated as unrelated.E11.22 and I12.9 — order by the reason for the encounter — then N18.4 once. N18’s Code First note names both the diabetic and the hypertensive combination codes; the stage is reported a single time.
3. Type 2 diabetes with ESRD on hemodialysis; documentation also says “CKD stage 5.”E11.22 → N18.6 → Z99.2, plus the Z79 code. N18.6 only, per I.C.14.a.1, when both a stage and ESRD are documented; N18.5 carries an Excludes1 for CKD requiring chronic dialysis (N18.6).
4. Type 2 diabetes; CKD stage 3b; the nephrologist documents the CKD as due to polycystic kidney disease, not diabetes. The provider has stated the conditions are unrelated, so the “with” presumption does not apply: the diabetes is coded without the kidney complication (E11.9 if no other complication, or the applicable E11.- code), the polycystic disease is coded, and N18.32 follows the kidney disease it is associated with. Section I.A.15 reasoning; when the record is ambiguous rather than explicit, query.

• Reporting E11.22 without the N18 stage code — the combination code lacks the stage; the Use Additional Code note is not optional when the stage is documented.
• Sequencing N18 first — N18 carries a Code First note for the diabetic CKD code; it is never the lead of that pair.
• Coding E11.9 plus N18.x because the note does not say “due to diabetes” — the “with” convention presumes the link; only a statement that the conditions are unrelated breaks it.
• Confusing E11.21 with E11.22 — E11.21 is diabetic nephropathy (inclusion terms include Kimmelstiel-Wilson disease); E11.22 is diabetic chronic kidney disease. They are different documented conditions, not synonyms.
• Reporting N18.5 with N18.6, or a stage code with N18.6 — N18.6 alone when ESRD is documented.
• Dropping the hypertension combination code when hypertension is also documented — I12 (or I13) is assigned alongside the diabetes code, with one N18 code for both.
• Assigning Z79.4 for a temporary insulin course during the encounter — I.C.4.a.3 excludes it.

• Type of diabetes. Absent, the default is type 2; “insulin-dependent” does not mean type 1. A documented underlying cause (pancreatic disease, Cushing’s, a drug) moves the code to E08, E09 or E13.
• CKD stage, or ESRD. The stage code is taken from the provider’s documentation; 3a and 3b are separate codes. ESRD outranks any stage.
• A statement that the CKD is unrelated to the diabetes (or, for I12, unrelated to the hypertension). This is the only thing that removes the combination code; clinical plausibility is not a coding rule in either direction.
• Dialysis dependence — adds Z99.2 with N18.6.
• Control agents in current use — determines which Z79 codes apply.
• Kidney transplant status. CKD after a transplant is N18 stage + Z94.0, and is not itself a transplant complication (I.C.14.a.2).