What is the condition that is chiefly responsible for the admission of the patient to the hospital?

June 26, 2020 / By Audrey Howard, RHIA

In my opinion, one of the hardest aspects of coding is selecting the principal diagnosis. It is not simply assigning a code to a documented diagnosis. It takes critical thinking to ascertain “that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.” (Uniform Hospital Discharge Data Set definition of principal diagnosis). As often stated in AHA Coding Clinic, the sequencing of the principal diagnosis depends on the circumstances of the encounter. There is no shortcut to appropriately selecting the principal diagnosis. The coder must read through all reports and provider documentation to accurately identify that one condition which required the inpatient admission. But what happens when the patient is admitted with several conditions? There still can be only one principal diagnosis. 

The first thing I do when I review a record of a patient admitted with multiple diagnoses, which could potentially meet the principal diagnosis definition, is separate out the conditions and evaluate each one individually. I ask myself these questions for each condition:

• Did this condition necessitate inpatient admission? Would the patient have been admitted to the inpatient setting for this condition? 
• Did this condition meet admission criteria? Was the patient sick enough? Was the treatment significant enough?
• Could this condition stand alone as the reason for admission?

If the answer to these questions is yes, then I can consider sequencing the condition as principal diagnosis. Let’s take a look at the following example:  A 65-year-old female presented through the Emergency Department with a chief complaint of weakness, fatigue and dyspnea/shortness of breath on exertion for the past week. The patient also complained of dysuria for the past month. The patient was alert, cooperative, and in no apparent distress without fever or chills. The chest was clear bilaterally with no rales, rhonchi or wheezing. No accessory muscle use or stridor. A COVID-19 test came back negative with no known exposure. The patient was noted to have 3+ bilateral pitting edema up to the knees. The following table shows a summary of the pertinent information:

The final diagnoses included UTI and DVT. Sepsis was ruled out. The provider never documented pulmonary embolism. Do we have a choice for principal diagnosis in this example? Based on the circumstances of admission and the existing documentation, the only option for principal diagnosis is UTI. A query related to pulmonary embolism would have been appropriate because the patient had signs and symptoms related to it on admission (dyspnea on exertion, tachycardia, elevated D Dimer) and it was treated (heparin, Eliquis) even though the CT PE only showed small peripheral emboli. What final corresponding diagnosis, if any, would the provider be willing to add to explain the symptoms? The DVT was not supported as principal diagnosis. Although the pitting edema was present on admission and the patient was started on heparin on admission, if I evaluate the DVT by itself, I cannot conclusively answer “yes” to all the questions I listed previously. After study, it does not appear to be the condition necessitating the inpatient status. The presenting signs and symptoms of weakness, fatigue, dysuria support UTI as the principal diagnosis. Although UTI does not always require inpatient care, it does appear to be the reason for admission in this case, especially since a diagnosis of sepsis was ruled out.

When reviewing the record for principal diagnosis selection, I take a step back and ask myself “What was the reason for the admission at that time?”  Another way of looking at this is to try and determine the intent of the admission. Sometimes, when the patient is transferred to the facility, the intent of the transfer will take sequencing priority over other conditions the patient brings with them. If the other conditions could have been treated appropriately at the first facility, then they would not be sequenced as the principal diagnosis at the second facility. The reason for the transfer would be sequenced as the principal diagnosis. 

For example, a patient was transferred from facility A to facility B due to worsening kidney function. The patient was originally admitted to facility A five days prior to transfer due to sepsis with an infected heel ulcer and was treated with IV antibiotics. According to the documentation, the patient received an incision and debridement at facility A for treatment of the heel ulcer. It was planned for the patient to receive further surgical debridement at facility A. However, due to the worsening kidney function, the surgery could not be completed at facility A at that time and the patient was transferred to facility B for care of the acute kidney failure. The principal diagnosis is the reason (intent) for transfer – the acute kidney failure. After the kidney function improved, the patient underwent surgery for care of the left heel. Neither the sepsis nor the heel ulcer should be sequenced as principal diagnosis at facility B because they did not necessitate the transfer for care.

Before finalizing the principal diagnosis selection, the coding professional also needs to apply any official coding guideline or convention that takes precedence and directs that one condition is sequenced as principal diagnosis over another condition. A good example of this is sepsis due to pneumonia. Although both conditions can necessitate inpatient admission, meet admission criteria and stand alone as the reason for admission, the sepsis coding guideline states that the systemic infection must be sequenced as principal diagnosis over the localized infection which does not allow for a choice between the two conditions;  therefore, sepsis is sequenced as principal diagnosis. 

There are definitely a lot of things to consider when selecting the all-important principal diagnosis. Happy sequencing!

Audrey Howard, RHIA, is a senior outsource services consultant with 3M Health Information Systems.

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Q: When two conditions are both present on admission, both meet definition to be the principal diagnosis, and are “equally treated,” my understanding is that the condition does not have to be "equally treated" in the sense of duration/frequency. Can you provide the actual verbiage of the coding rule and explain?

A: The instruction can be found in Section II of the Official Guidelines for Coding and Reporting for Selection of Principal Diagnosis. It states that the circumstances of inpatient admission always govern the selection of principal diagnosis. Furthermore, the Guidelines refer to the rules outlined in CMS’ Uniform Hospital Discharge Data Set (UHDDS) as “that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.” (The UHDDS definitions are used by hospitals to report inpatient data elements in a standardized manner.)

The Guidelines further state that “in determining principal diagnosis, coding conventions in the ICD-10-CM, the Tabular List and Alphabetic Index take precedence” over the Guidelines. Section II.C., contains rules governing code assignment for two or more conditions that equally meet the definition for principal diagnosis. It states that “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.”

CDI professionals need to read the Official Guidelines for Coding and Reporting, in its entirety, particularly the sections governing principal diagnosis selection.

To reiterate, first and foremost the selection of the principal diagnosis is based on the circumstances of the admission as stated above, followed by any instructions received in the coding conventions, such as a “code first” note (these instructions or conventions are only found in a code book, you will not find them in the DRG Expert), followed by the advice found in the Official Guidelines for Coding and Reporting, and lastly by any instruction/advice given in the America Hospital Association’s Coding Clinic for ICD-10-CM/PCS published every year on a quarterly bases.

There is no rule as to treatment having to be “equal.”  Sometimes the provider may determine no treatment (such as medication or surgery) is the best course of action for a patient, maybe monitoring the patient at a different level of care, for instance in the ICU versus placement on a medical/surgical floor is best. It really would depend on the circumstances of the admission.

Editor’s Note: Sharme Brodie, RN, CCDS, CCDS-O, CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts, answered this question. For information, contact her at . For information regarding CDI Boot Camps, click here.