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All-Patient Diagnosis Related Group (AP-DRG)

What is an All-Patient Diagnosis Related Group (AP-DRG)?

An All-Patient Diagnosis Related Group (AP-DRG) is a classification system that categorizes patients based on their reason for admission, illness severity, and mortality risk. They are an extension of Diagnosis Related Groups (DRGs) that also account for illness severity and mortality risk.

AP-DRGs were developed by 3M Health Information Systems in partnership with the National Association of Children’s Hospitals (NACHRI). They are widely used for payment, public reporting, and severity adjustment in quality assessment initiatives.

Patients begin by receiving a base AP-DRG from their principal diagnosis (for medical patients) or their most important surgical procedure. Then, each base AP-DRG is divided into four subclasses based on illness severity and mortality risk: minor, moderate, major, and extreme. Both severity of illness (SOI) and risk of mortality (ROM) are calculated separately and can differ from each other.

When assigning illness severity and mortality risk subclasses, consideration is taken of the interactions among age, principal and secondary diagnoses, and procedures (if applicable).

How are All-Patient Diagnosis Related Groups (APDRGs) important for healthcare?

The primary benefit of an AP-DRG is that it is the only inpatient classification method applicable to all patient populations, no matter their age. AP-DRGs also group together patients who require the same intensity for resources and a similar clinical perspective.

What is the difference between a DRG, MS-DRG, and AP-DRG?

Diagnosis-related groups can come in a few different categories, with each different type accounting for different medical factors. A basic DRG only measures a patient’s resource utilization while staying at a hospital on one or two levels of severity.

The “MS” in MS-DRG stands for “Medicare severity” and refers to DRGs given specifically to Medicaid and Medicare patients. Additionally, an MS-DRG measures the patient’s severity of illness and risk of mortality while admitted on up to three levels of severity.

AP-DRGs are similar to regular and MS-DRGs but also include a more detailed DRG breakdown for non-Medicare patients, particularly newborns and children.