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3M™ International Refined-DRGs (3M IR-DRGs)

Flags for multiple countries
International grouping and classification for hospitals, payers and researchers

Providing consistent DRG assignment regardless of the coding system

3M IR-DRGs are designed for all patient populations, including pediatrics and obstetrics, and for all patient settings except long-term care.

The 3M International Refined-DRG (IR-DRG) methodology compares resource consumption across facilities and regions, supporting both local and national health system management.

Clinician moving a patient in a hospital bed
3M IR-DRGs: Designed for all patient populations, globally.

Capturing both inpatient and ambulatory encounters in one seamless system using one geographically agnostic system.


Why choose the 3M™ IR-DRGs?

  • Phycisians talking
    A single classification method to cover inpatient and outpatient care

    The 3M IR-DRGs allow grouping for encounters that occur in both inpatient and ambulatory settings. Addressing the recent shift in health care services to outpatient settings, 3M IR-DRGs also cover same-day interventions, emergency department (ED) visits and other acute care ambulatory services.

  • Flexible
    Flexible to use with different diagnosis and procedure coding systems

    3M IR-DRGs are designed specifically for international health care, but are not limited to any particular country. While developed by 3M based on the DRG classifications in the United States, this classification system is geographically agnostic and can support the diverse coding classification systems used worldwide. 3M IR-DRGs provide consistent DRG assignment regardless of the coding system used.

  • Clinical staff
    Provide insights into expected resource consumption based on patient severity of illness

    For the inpatient component, 3M IR-DRGs incorporate the concept of severity adjustment. Taking under account patient’s comorbidities, complications, and secondary diagnosis, the base DRGs are organized into three sub-classes of severity of illness and risk of mortality.

  • Dad and child
    A basis for measuring and improving outcomes

    The 3M IR-DRG methodology also includes the assignment of risk of mortality (ROM), which is an important outcome parameter for quality of inpatient care. Severity adjustment helps to describe relative resource consumption across health care services.

All about 3M IR-DRGs

The 3M IR-DRG methodology is versatile and code-independent, meaning that 3M IR-DRGs provide the same results in classifying patients regardless of the type of coding systems used.

  • Definition

    The 3M IR-DRG patient classification methodology discriminates between inpatient and ambulatory encounters, while consistently grouping cases with similar resource consumption. Each 3M IR-DRG code describes patients who are similar both clinically and in their resource consumption.

  • 3M IR-DRGs are used by payers, hospitals and researchers worldwide as part of funding systems and for budgeting, outcomes analysis, benchmarking, performance measures and utilization assessment. The classification system can compare resource usage across facilities and regions and support local and national health system management.

  • The 3M IR-DRGs are designed for all patient populations, including sick and healthy newborns, pediatrics and obstetrics and for all patient settings except long-term care. The 3M IR-DRG classification system can group all types of inpatients and ambulatory patients, including:

    • Hospital inpatients
    • Clinic
    • Hospital same-day
    • Office visit
    • Hospital clinic
    • Rehabilitation
    • Emergency department
    • Chemotherapy and radiation therapy

    The 3M IR-DRGs are currently used in various health care systems around the world, including Hong-Kong, Chile, the United Arab Emirates, the Czech Republic and Spain.

  • 3M IR-DRG classification logic is the same for every user, although different organizations may use different versions. (The most recent version is recommended.) Each licensee makes its own decisions about appropriate uses. At this time, 3M does not offer software that replicates the 3M IR-DRG analysis used in specific countries.

  • The 3M IR-DRG methodology is derived from and integrated with other 3M patient classification methodologies. For example:

    • The 3M IR-DRG logic for inpatient care is based on the 3M™ All Patient Refined Diagnosis Related Group (APR DRG) methodology that is widely used in the U.S. for payment and risk adjustment. Countries such as Spain and Belgium also use the 3M APR DRGs for reporting and payment adjustment.
    • The 3M IR-DRG logic for ambulatory care (e.g., emergency departments, other hospital outpatient departments, physician clinics, etc.) is based on the Ambulatory Payment Classifications (APCs), the widely used outpatient classification system developed in the U.S. by the Centers for Medicare & Medicaid Services (CMS).
    • The 3M IR-DRGs also provide risk adjustment in measuring inpatient mortality using the risk-of-mortality (ROM) subclasses to evaluate inpatient quality outcomes. For inpatient complications, the 3M™ Potentially Preventable Complications (PPC) methodology is applied, and for readmissions, the 3M™ Potentially Preventable Readmissions (PPR) methodology is used.
  • The 3M IR-DRGs are available in the following 3M products:

    • 3M™ Core Grouping Software (CGS)
    • 3M™ Coding and Reimbursement System (for ICD-10-CM/PCS and CPT® code sets)
  • 3M experts are available to advise government agencies, hospitals, third parties and other interested entities on how to obtain maximum value from the use of the 3M IR-DRGs. For example, 3M consultants can help you assess options for improving payment methods, implementing patient classification methods, adapting the 3M IR-DRGs to country-specific code sets, and measuring and improving health care outcomes.

  • The 3M IR-DRG classification system is a robust choice for the international market because it provides consistent classification for patients regardless of the coding systems used, making international comparisons possible. 3M IR-DRGs use procedures rather than principal diagnosis as a starting point to better align with ambulatory components and reduce redundancy.

    All the data required to assign a 3M IR-DRG code can be obtained from standard patient records. Crucial data fields for 3M IR-DRG assignment include all procedure and diagnosis codes, present-on-admission indicators (POAs), procedure code dates, length of stay and basic patient demographics.

  • The first version of the 3M International Refined-Diagnosis Related Groups (IR-DRGs) was developed to provide a patient classification system that would result in the same 3M IR-DRG assignment regardless of the coding system used. The system encompasses a wide variety of coding systems, providing an accurate basis for comparing inpatient utilization across countries.

    The development objective of the second version of the 3M IR-DRGs is to create a single 3M IR-DRG classification system that can group all types of patients. Many international patients previously evaluated and treated in an inpatient setting are now being evaluated and treated in an ambulatory setting, and in many countries, there is not a clear distinction between inpatient and ambulatory care. This trend created the need for a single 3M IR-DRG system that spans the complete continuum of care settings.

    Since 3M IR-DRG version 2.0, the 3M IR-DRGs have encompassed all patient settings except long-term care. 3M IR-DRGs can group all types of inpatients and ambulatory patients.

    The system’s inpatient component is derived from the 3M™ All Patient Refined-DRG (APR DRG) Classification System and includes three levels of adjustment for severity of illness to better capture the complexity of modern health care using fewer categories than other DRG systems. The core ambulatory component is derived from 3M Ambulatory Patient Groups (APGs), predecessor of the 3M Enhanced Ambulatory Patient Grouping (EAPGs), and the Ambulatory Payment Classification (APCs), developed for Centers of Medicare and Medicaid Services.

    3M IR-DRGs use different procedure types and categories to discriminate between procedural groups and allocate specific Major Diagnostic Categories (MDCs), when applicable. Unlike other less sophisticated grouping methodologies, 3M IR-DRGs natively support ICD-10 WHO and ICD-10-CM (USA) diagnoses, ICD-10 PCS (USA) procedures, CPT® interventions classification, as well as variants and predecessor versions such as ICD-9-CM.

    The latest version of 3M IR-DRGs uses the full capacity of the ICD-10-CM diagnosis and intervention codes. This helps to link with quality and outcome measures by using indicators from the 3M™ Potentially Preventable Readmissions (PPR) Grouping Software. Indicators from the 3M™ Potentially Preventable Complications (PPC) Grouping Software are also used to identify present-on-admission flags and generate admission and discharge data for the 3M IR-DRGs.

    3M IR-DRGs are continuously maintained to reflect current knowledge and classifications used worldwide, accommodating country-specific modifications and procedure coding systems. The 3M IR-DRG classification system contains the powerful severity-of-illness (SOI) subclasses for payment and production efficiency measurement and the risk-of-mortality (ROM) subclasses to evaluate quality.

    3M calculates and releases a set of statistics for each version of 3M IR-DRG based on our analysis of large, national data sets. These statistics include a relative weight for each 3M IR-DRG. The relative weight reflects the average resource use for a patient in that 3M IR-DRG relative to the average 3M IR-DRG. Please note that payers and other users of the 3M IR-DRG methodology are responsible for using relative weights appropriate for their populations.

    Further information on the 3M IR-DRG logic is available in the 3M IR-DRG white paper (PDF, 475 KB). The 3M IR-DRG logic is proprietary to 3M and maintained by a team of 3M clinicians, data analysts, nosologists, programmers and economists. The methodology is updated annually to reflect changes in the standard diagnosis and procedure code sets as well as 3M enhancements to the clinical logic.

Learn more about 3M IR-DRGs

Publicly available documentation, articles and reports

Please note that documents not published by 3M do not necessarily reflect 3M recommendations and have not been approved by 3M. These documents are listed here for the information of readers interested in the various ways that 3M patient classification methodologies have been applied. Also note that listing these references does not imply endorsement of 3M methodologies by individual authors, other organizations or government agencies.

Some articles and reports are available from the publishers at no charge, while others require a fee.

  • This white paper describes the structure and features of the 3M™ International Refined-DRGs (IR-DRGs) and assesses the validity of a new approach to standardizing the definitions of hospital inpatient and ambulatory services.

  • The Abu Dhabi government selected 3M International Refined-DRGS (IR-DRGs) because the methodology allowed its health leaders to customize use based on the local health care system and requirements. This in-depth article outlines the application of Diagnosis Related Groups in Abu Dhabi.

  • This article describes the application of diagnosis related groups (DRGs) in Chile to standardize and measure the treatment of various pathologies, as well as the resources required. This article includes a summary in English; the main article is in Spanish.

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