A patient arrives at the ED with acute respiratory failure and congestive heart failure. The patient is admitted to the hospital and the physician treats both conditions. The physician documents "acute respiratory failure due to exacerbation of congestive heart failure." What is the principal diagnosis?
Coders and CDI specialists may not see eye to eye on it.
"Anytime you have acute respiratory failure and another condition, that causes disagreements," says Cheryl Ericson, MS, RN, CCDS, CDIP, CDI education director for HCPro, a division of BLR in Danvers, Mass.
The ICD-9-CM Official Guidelines for Coding and Reporting and the Uniform Hospital Discharge Date Set (UHDDS) define the principal diagnosis as the "condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care."
The UHDDS definition of principal diagnosis hasn't changed since 1985, but what constitutes or supports an inpatient admission has.
"We didn't have medical necessity for setting reviews five years ago," Ericson says.
As a result, when two conditions both met the criteria for principal diagnosis, coders could go to the one with higher reimbursement, pick that as the principal diagnosis, and suffer no penalty.
"It's only been in the last five years that we've seen medical necessity be a huge penalty because when you get a medical necessity denial, you lose all of the reimbursement," Ericson says.
In 2012, CMS released MLN Matters® SE1027, which showed heart failure (DRG 127) as the second most likely diagnosis to fail to meet medical necessity criteria.
Cardiac defibrillator implants (DRG 514/515) failed most often to meet medical necessity.
Another problem is that coders may not know when a case is denied for medical necessity because those denials are usually handled by case management, Ericson says.
Sequencing matters
The ICD-9-CM Official Guidelines for Coding and Reporting further state:
In the unusual instance when two or more diagnoses equally meet the criteria for principal diagnosis as determined by the circumstances of admission, diagnostic workup and/or therapy provided, and the Alphabetic Index, Tabular List, or another coding guidelines does not provide sequencing direction, any one of the diagnoses may be sequenced first.
Coders will often look to see what caused the acute respiratory failure. In the above case, the physician documented that the patient was in respiratory failure because his or her congestive heart failure worsened. That leads many coders to choose congestive heart failure as the principal diagnosis.
By sequencing the congestive heart failure first, the coder ends up at a higher weighted MS-DRG. Acute respiratory failure is an MCC as a secondary diagnosis when paired with the heart failure MS-DRG.
Ericson, a former ED nurse, says her bias is toward acute respiratory failure. "If someone isn't breathing, they're dead."
Both the acute respiratory failure and congestive heart failure could be coded as the principal diagnosis. However, "In my opinion, there is a big difference between acute respiratory failure and heart failure in regards to occasioning the admission," Ericson says. "CMS is teaching us that people don't need inpatient care for heart failure. They do need inpatient care for acute respiratory failure."
So from a clinical perspective, CDIs would sequence the acute respiratory failure first. "The patient would not be admitted for congestive heart failure unless he or she was in acute respiratory failure. Otherwise they won't meet inpatient criteria." The patient is usually discharged when his or her respiratory status has stabilized (returned to baseline) because the patient will continue to have heart failure and it can be successfully treated in the outpatient setting. Consequently, the condition being treated is the acute respiratory failure, but in order to treat it, the heart failure must also be addressed.
The documentation is not always so clear, Ericson says. "The provider often states the patient is being admitted for 'shortness of breath' rather than using the diagnosis of acute respiratory failure, which makes it that much easier to sequence heart failure as the principal diagnosis because 'shortness of breath' is a symptom and heart failure is a diagnosis."
One important question is whether both conditions actually meet the definition of a principal diagnosis. The ICD-9-CM guidelines for sequencing acute respiratory failure specifically instruct coders:
If the documentation is not clear as to whether acute respiratory failure and another condition are equally responsible for occasioning the admission, query the provider for clarification.
Etiology/manifestation
Coders will sometimes apply etiology/manifestation guidelines, which require the etiology be sequenced before its manifestation, whenever they see a physician document that one condition is due to another, Ericson says. "However, etiology manifestation only apply to a few conditions like diabetes and its manifestations. It isn't a blanket guideline that applies to all disease processes as most conditions are caused by something else."
Whenever such a combination exists, coders will see a "code first" note in the ICD-9-CM Manual under the manifestation code and a "use additional code" instruction under the etiology code. The ICD-9-CM Manual instructs coders to first report the etiology code, followed by the manifestation code(s).
Many times the manifestation code will include the words "in diseases classified elsewhere" in the code title. Coders should never use conditions "in diseases classified elsewhere" as the principal diagnosis.
For example, under code 358.1 (myasthenic syndromes in diseases classified elsewhere), coders will find a note to code first the underlying disease. If the myasthenic syndrome is due to pernicious anemia, coders would report 281.0 (pernicious anemia) followed by 358.1.
For patients suffering from other sickle-cell disease with crisis (282.69), coders are instructed to use an additional code to identify the type of crisis.
Another example is secondary hypertension (405.xx). The ICD-9-CM Official Guidelines for Coding and Reporting state that two codes are always required: one to identify the underlying etiology and one for the secondary hypertension. The sequencing is dependent on the circumstances of the admission.
"If the cause is the focus on the treatment, then the cause is the principal diagnosis, followed by the secondary hypertension," Ericson says. "But if the focus is on the secondary hypertension, even though the cause is something else, the secondary hypertension is the principal diagnosis followed by the etiology. This is one of many examples where the etiology is not automatically sequenced before the manifestation even though the secondary hypertension will always be caused by another condition."
After study
What types of things require study? Symptoms. The ICD-9-CM Official Guidelines for Coding and Reporting state:
If a definitive diagnosis has not been established by the end of the encounter, it is appropriate to report codes for sign(s) and/or symptom(s) in lieu of a definitive diagnosis. In other words, if after study, a definitive diagnosis cannot be reported, then sign(s)/symptom(s) can be reported. However, in the inpatient setting, the purpose of the admission is often to evaluate and treat a condition so it should be rare for the provider to be unable to link the presenting symptoms to an associated diagnosis. Additionally, with the prevalence of CDI queries can be issued to ask the provider if there are any relevant uncertain diagnoses at the time of discharge to explain the symptom.
So the ICD-9-CM guidelines and the UHDDS definition of principal diagnosis, "the condition after study chiefly responsible for occasioning the admission" is really reinforcing that symptoms can't be reported as the principal diagnosis, Ericson says.
The phrase 'after study' is not the same as 'due to.'
Editor’s note: This article was originally published in the April issue of Briefings on Coding Compliance Strategies.Email your questions to Senior Managing Editor Michelle A. Leppert, CPC, at mleppert@hcpro.com.