Pinson&Tang Resources

What is CDI?

March 11, 2022

CDI, or Clinical Documentation Integrity, can be understood as a process aimed at improving the accuracy of medical record documentation and coding for quality and reimbursement purposes. Throughout this article we will discuss the evolution of clinical documentation and the strategies and guidelines used today as explained in the CDI Pocket Guide®.

A Brief History of Clinical Documentation

Before answering the question “what is CDI” we have to give a brief history. Prior to 1983, hospitals would bill Medicare or the insurance company based on a charge for every supply and service provided, such as medications, bandages, labs, x-rays, daily room and bed charge, and Medicare would pay a percentage of these “total charges.” This caused long hospital stays where as many services as possible were done for the patient, i.e., the more services provided, the higher the reimbursement.

Inpatient Prospective Payment System (IPPS)

As a result, the Inpatient Prospective Payment System (IPPS) was introduced by the federal government in 1983 to curb skyrocketing healthcare costs for Medicare patients. The objective of the IPPS was to change hospital behavior through financial incentives that encourage more cost-efficient management of medical care. Under the IPPS, hospitals are paid a predetermined, fixed rate based on average costs for each medically necessary Medicare inpatient admission based on a diagnosis-related group (DRG).

Diagnosis-Related Group

The DRG system is an inpatient classification scheme that categorizes patients who share similar clinical characteristics and costs. Each inpatient discharge is classified into a DRG based on the numerical ICD-10 coded data submitted by the hospital on the billing claim.

Selecting the Appropriate ICD-10 Code

ICD-10 coding is the process of transforming disease, injury, and procedure descriptions into alpha-numeric codes. ICD-10-CM (International Classification of Diseases, Tenth Revision, Clinical Modification) is the coding classification system used to code diagnostic and operative procedural data for official morbidity and mortality statistics in the United States.

The ICD-10 billed codes must be supported by the medical record documentation of the physician and substantiated by clinical findings. For example, if the hospital bills a diagnosis code for pneumonia, physician documentation must include a diagnosis of pneumonia, and the clinical findings and treatment provided must also substantiate it. This is why correct CDI is so important.

Ensuring the Correct Principal Diagnosis

Correctly identifying the principal diagnosis and significant surgical procedures are the most important factor in DRG assignment. The principal diagnosis code is the first code listed on the hospital claim and is defined as “that condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care.”  The coding professional must assign the principal diagnosis based on all physician documentation found in the entire record applying official coding guidelines and instructions which are usually unfamiliar to physicians.

All other conditions either present on admission or that develop subsequently may qualify as secondary diagnoses if they affect patient care. CMS has designated certain of these conditions as CCs (comorbidities or complications) and MCCs (major CCs) that may affect DRG assignment.

Determining the DRG Payment

The DRG payment for a hospital inpatient is determined by multiplying the relative weight for the DRG by the hospital’s payment rate. Medicare calculates the DRG relative weights and hospital blended payment rates annually.

For example, a patient admitted with a principal diagnosis of congestive heart failure is assigned to DRG 293 (Heart Failure w/o CC/MCC), which has a relative weight of 0.5899. If the hospital payment rate is $7,000, the hospital’s reimbursement for this patient is determined by multiplying 0.5899 by $7,000. The payment to the hospital for this patient would be a flat fee of $4,129.

The DRG relative weight reflects the expected average length of stay, severity of illness, resource utilization and the relative cost of treating patients in this DRG.

The coding process is extremely important since it determines what DRG will be assigned for a patient, which, in turn, determines hospital reimbursement. Coding an incorrect principal diagnosis or procedure or failing to code a pertinent secondary diagnosis can significantly affect DRG assignment and the hospital reimbursement. Coded data is also used to determine physician reimbursement, publicly reported physician and hospital profiles, mortality and complication ratings, and other outcome measures.

The Benefits of Clinical Documentation Integrity

So, to fully understand “what is CDI”, let’s talk about the program itself. A Clinical Documentation Integrity (CDI) program is designed to clarify imprecise and incomplete provider documentation. A CDI program not only helps physicians with documentation improvement but ensures the correct translation of physician documentation to the proper ICD-10 codes submitted on the hospital claim. This in turn will ensure that the illness severity in patients is accurately reflected, and proper payment for the care provided is received.

The CDI team is multidisciplinary and includes clinicians, clinical documentation specialists, and coders. All these stakeholders play a crucial role in ensuring precise documentation and correct coding that accurately reflects the true illness severity of our patients.

Clinical Documentation Integrity Specialists

Clinical Documentation Integrity (CDI) Specialists are employed by hospitals to concurrently review patients’ medical records, assign a working DRG and determine if the documentation accurately reflects severity of illness if the patient. The CDI specialist queries clinicians for clarification when an improvement opportunity is identified, such as clinical findings supporting a more specific or additional diagnosis not yet documented, or when there is conflicting or confusing diagnostic or procedural information. Clear and precise documentation paints the true nature of the patient’s condition that supports correct coding and DRG assignment.


Why is this important?  In addition to hospital reimbursement, physician documentation drives practically all the major quality outcome measures. Outcome measures are used to stratify the performance of hospitals and physicians from best to worst. Medicare, Healthgrades, and news organizations such as US News and World Report publicly report hospital and physician quality and outcome measures.

How CDI Works

Hospital reimbursement and outcome measures are derived from the documentation in the medical record which are translated by the coder into ICD-10 codes on claim forms. Billing claims with the ICD-10 codes are submitted to Medicare, Medicaid and commercial payers. All claims data is stored in databases and analyzed to evaluate many aspects of healthcare. The largest is Medicare’s claims database, called MedPAR, which is used by many agencies and organizations to generate outcome and performance measures, such as mortality rates, complication rates, readmission rates, and costs.

For example, CMS HospitalCompare.com publishes hospitals' reported mortality rates for COPD, heart attack, heart failure, pneumonia, stroke, and coronary bypass surgery based on a star-rating. One star is defined as “worse than expected”, three stars is “as expected” and five stars is for “better than expected”. This information is publicly available and may discourage patients from seeking care at this hospital. But is the quality of care poor, or is there actually a documentation or coding problem that is creating a false picture of performance?


An 80-year-old female with preexisting cachexia and 30-pound weight loss in the past three months is admitted with UTI, blood pressure 70/50, heart rate 130, respiratory rate 28, pulse oximetry 85% on room air, WBC 25,000, lactate 4.2. Her hospital length of stay was 6 days, and she expired.

Provider A Provider B
Urosepsis Hypotension Hypoxemia Leukocytosis Cachexia Sepsis due to UTI Septic shock Respiratory failure Severe malnutrition

The above illustrates how physician documentation may influence the reporting of sepsis mortality rates. Provider A’s documentation included urosepsis which is classified as a simple UTI, and hypotension, hypoxemia, leukocytosis, and cachexia are classified as rather insignificant findings in the absence of specific diagnoses. Severity of illness for this case is classified as nothing more than a UTI with no significant comorbidity. Had physician documentation been more precise and specific as shown for Provider B, the illness severity and high risk of mortality would have been more accurately reported, that is, septic shock with respiratory failure and severe malnutrition.


What Is CDI - A Summary

In summary, when you ask, “what is CDI”, this refers to the documentation that drives nearly all the major outcome measures and reimbursement. Precise physician documentation that translates into the correct codes to accurately reflect the patient’s severity of illness is absolutely necessary.

CDI experts, Dr. Richard Pinson and Dr. Cynthia Tang, understand the importance of accurate documentation and have developed an all-encompassing CDI Pocket Guide® to help hospitals and providers improve the efficiency and accuracy of medical record documentation and coding.

Click now to learn more about CDI resources and programs.

© 2022 Copyright Pinson & Tang LLC

See our original CDI Pocket Guide® for more information on this topic.

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