How Do I Code Secondary Diabetes? E08 Due to an Underlying Condition, E09 Drug-Induced, or E13 Other Specified

Official source

“Codes under categories E08, Diabetes mellitus due to underlying condition, E09, Drug or chemical induced diabetes mellitus, and E13, Other specified diabetes mellitus, identify complications/manifestations associated with secondary diabetes mellitus. Secondary diabetes is always caused by another condition or event (e.g., cystic fibrosis, malignant neoplasm of pancreas, pancreatectomy, adverse effect of drug, or poisoning).”

The sequencing rule is delegated to the tabular: “The sequencing of the secondary diabetes codes in relationship to codes for the cause of the diabetes is based on the Tabular List instructions for categories E08, E09 and E13.” Those instructions differ. Category E08 says “Code first the underlying condition, such as: congenital rubella (P35.0), Cushing’s syndrome (E24.-), cystic fibrosis (E84.-), malignant neoplasm (C00-C96), malnutrition (E40-E46), pancreatitis and other diseases of the pancreas (K85-K86.-).” Category E09 says “Code first poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4)” and “Use additional code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5).” Category E13 carries no Code First note; its Includes note lists postpancreatectomy, postprocedural and secondary NEC diabetes and diabetes due to genetic defects of beta-cell function or insulin action.

All three exclude one another and E10; E08 and E09 also carry an Excludes1 for E11, and E11’s Excludes1 names all three, E13 through its postpancreatectomy, postprocedural and secondary NEC entries — a documented secondary diabetes is not also coded as type 2 — and all three carry the same Z79 Use Additional Code note as E11, with the same rules in I.C.4.a.6.a.

1. Identify the documented cause. A disease (pancreatitis, cystic fibrosis, Cushing’s, a neoplasm) → E08. A drug or chemical → E09. A pancreatectomy or other procedure, a genetic defect, or a cause documented but not fitting E08/E09 → E13.
2. Select the complication character exactly as for E11 — .22 CKD, .40 neuropathy, .65 hyperglycemia, .9 without complications — the subcategory structure is parallel.
3. Sequence by the category’s note. E08: the underlying condition first. E09: a poisoning (T36–T65, character 1–4) first; an adverse effect (T36–T50, character 5) after the E09 code — the two directions of the poisoning guide. E13: no Code First note; for pancreatectomy, Section I.C.4.a.6.b.i assigns E13 as principal or first-listed with E89.1 and Z90.41- as additional codes — the postpancreatectomy guide walks that case.
4. Add the Z79 control code(s) under I.C.4.a.6.a, and any external cause code the poisoning rules require.

1. Diabetes documented as due to chronic pancreatitis, no complications, on insulin. The pancreatitis code first (E08’s Code First note), then E08.9, then Z79.4.
2. Diabetes documented as an adverse effect of long-term corticosteroid therapy, correctly prescribed; no complications.E09.9, then the T36–T50 adverse-effect code for the steroid with 5th/6th character 5 — the Use Additional Code direction, because the drug was properly administered.
3. Diabetes following total pancreatectomy. A code from E13 first, then E89.1 and a Z90.41- code, per I.C.4.a.6.b.i.

• Coding E11 for a documented secondary diabetes — E08 and E09 each carry an Excludes1 for type 2, and E11’s Excludes1 names E08, E09 and E13.
• Sequencing E08 before its underlying condition — the Code First note orders it.
• Using the poisoning column for a correctly prescribed drug — that is an adverse effect (character 5) and goes after E09, not before it.
• Coding E08 for postpancreatectomy diabetes — E08 carries an Excludes1 for it; E13 is the category.
• Omitting E89.1 and Z90.41- in the pancreatectomy case.

• The provider’s statement of the cause — a condition, a drug, a procedure — which selects the category; “secondary diabetes” with no cause named is E13 (secondary diabetes mellitus NEC is its inclusion term).
• Whether the drug was correctly prescribed and administered (adverse effect) or misused (poisoning).
• The complication(s) present, coded with the parallel subcategory characters.
• Control agents in current use.