Internal Medicine Coding Alert

Diagnosis coding for diabetes may seem straightforward, but even experienced coders can get tripped up by the fifth-digit catch-22.

With the sharp national rise in diagnoses of diabetes mellitus, it's particularly important that coders know the ins and outs of coding this disease.

To avoid getting mired in confusion, remember these three rules: Just because patients take insulin shots does not mean they are insulin-dependent. Just because patients are young does not mean they have Type 1 (or juvenile) diabetes. And just because glucose levels are out of normal ranges does not mean the diabetes is uncontrolled.

Choosing a Code

Use a diagnosis code in the 250.xx range for patients diagnosed with diabetes mellitus. (See sidebar on page 76 for other, less common types of diabetes.) You must select both a fourth and fifth digit to use with 250.

Use the fourth digit to identify complications, such as renal, ophthalmic, neurological and circulatory disorders. Fourth digits range from 0 (Diabetes mellitus without mention of complication) to 8 (Diabetes with other specified manifestations).

"If the complications affect the kidneys, eyes, nerves or peripheral circulation, then you should also use additional codes to identify the actual manifestation (e.g., blindness, nephrosis, etc.)," says Karen M. Beard, CPC, a senior associate at Medical Management Associates Inc., in Atlanta.

Often, diabetic patients develop a number of complications, and physicians are unsure which codes to use on the encounter form, says Jerome S. Fischer, MD, a board-certified internist and endocrinologist at Diabetes and Glandular Disease Clinic in San Antonio, and the author of Diabetes Care Documentation and Coding for Clinicians, published in 2002 by the American Diabetes Association.

"List only the complications that were addressed at this particular visit," Fischer says.

Typing Is Tricky

Now, the difficult part. You must choose a fifth digit to describe the type of diabetes that the patient has and to indicate if it is uncontrolled.

The choices are:
0 Type II (non-insulin dependent type) (NIDDM type) (adult-onset type) or unspecified type, not stated as uncontrolled

1 Type I (insulin dependent type) (IDDM) (juvenile type), not stated as uncontrolled

2 Type II (non-insulin dependent type) (NIDDM type) (adult-onset type) or unspecified type, uncontrolled

3 Type I (insulin dependent type) (IDDM) (juvenile type), uncontrolled.

The language that the ICD9 book uses in this section is particularly confusing, Fischer says, because it uses terms such as "insulin dependent" and "adult-onset type" that the American Diabetes Association (ADA) considers outdated. To avoid confusion, ignore the descriptors in the definitions and focus instead on the type of diabetes the patient has I or II as your first step toward selecting the proper fifth digit:

Type I Diabetes

Type I diabetes, called insulin-dependent, juvenile type in the ICD-9 book, is usually diagnosed at an early age and occurs when the patient's pancreas does not produce insulin. An autoimmune disease, it accounts for just 10-15 percent of diabetes mellitus cases.

"Almost all of these patients are diagnosed under the age of 30, usually in childhood or adolescence, thus, the term 'juvenile diabetes,' " Beard says. "They do not usually suffer from obesity. They require daily injections of insulin (or an insulin pump) and dietary controls to prevent diabetic coma with ketoacidosis or death."

Choose either 1 or 3 as the fifth digit for these patients: 1, if the disease has not been stated as uncontrolled in the documentation; 3, if the doctor has characterized the disease as uncontrolled.

Type II Diabetes

The other major form is Type II diabetes, called non-insulin dependent, adult-onset type in the ICD-9 book. This is the most common form, affecting about 90 percent of those with diabetes mellitus.

This type is often referred to as adult-onset diabetes because, in years past, Type II patients typically had no symptoms until after age 30. Today, however, even children are being diagnosed with Type II diabetes. Type II differs from Type I in that the patient's pancreas produces insulin. However, the body has become resistant to the insulin. Type II diabetics often manage their symptoms with diet, exercise and oral medicines. Insulin may be added if these measures fail, but it is not usually required at the onset, Beard says.

Choose either 0 or 2 as the fifth digit for these patients: 0, if the disease has not been stated as uncontrolled in the documentation; 2, if the doctor has characterized the disease as uncontrolled.

Still Confused?

Coders trying to choose a fifth digit are most often confused by two factors: insulin dependence and the patient's age.

If a Type II patient requires insulin shots, the coder may assume the patient is insulin-dependent and try to use one of the fifth digits for Type I diabetes. But remember: For coding purposes, it does not matter if the patient takes insulin shots. What's important is the type of diabetes he has.

Especially confusing is maturity onset diabetes of the young (MODY), a variant of Type II diabetes typically not diagnosed until after age 30, Beard says. These patients often have severe symptoms that necessitate insulin from the onset, but they are still classified as Type II, she says.

The other confusing factor is the patient's age. Type II diabetes is occurring in obese children and adolescents at a disturbing rate. So be careful in choosing the fifth digit for a young person. Read the doctor's notes carefully, because the young age of the patient at onset does not automatically mean the child has Type I (called juvenile diabetes in the ICD-9-CM book).

Coders may not have to wade though this confusing language in ICD-9-CM too much longer.

"ICD has lagged behind," says Fischer, who notes that the ADA revamped its diabetes diagnosis terminology several years ago. He says he hopes that the new ICD-10-CM book in development will reflect those changes and no longer use the confusing terms "insulin-dependent," "non-insulin-dependent," "juvenile" and "adult-onset" to describe the diabetes types.

Controlled or Uncontrolled?

Your last decision in choosing the fifth digit is whether the patient's disease is "uncontrolled." Many coders and physicians do not realize this is a determination that only the doctor can make.

Use 2 (for Type II) or 3 (for Type I) when the doctor states in the chart that the diabetes is uncontrolled; use 0 (for Type II) or 1 (for Type I) when the doctor has not stated in the chart that the disease is uncontrolled.

"It is very important for physicians to understand their role in correct ICD coding and that they should include the appropriate classification in the patient's chart," Beard says.

If the physician does not state "uncontrolled" in the documentation, a coder may not code the condition as "uncontrolled" based on abnormal glucose readings in the patient's chart, Beard says.

Physicians may base that determination on several factors, including the patient's in-office hemoglobin AIC levels, the patient's home monitoring results, the patient's report of symptoms and complaints, and the physician's own clinical impressions, Fischer says.

"If your physicians are selecting the ICD code from a preprinted form, make sure they have a full range of diabetes mellitus codes available and have been instructed to specify whether the DM is uncontrolled or controlled," Beard says.