Understanding Risk of Mortality (ROM) in Medical Coding

What is Risk of Mortality (ROM)?

Risk of Mortality (ROM) is a clinical severity measure used in healthcare coding and reporting that estimates the likelihood a patient will die during a hospital stay. ROM is typically assigned using coding systems like the APR-DRG (All Patient Refined Diagnosis Related Groups), which help stratify patients by the seriousness of their illness and the complexity of their medical conditions.

ROM is expressed in four levels:

• Minor (Level 1) – Very low likelihood of mortality.

• Moderate (Level 2) – Average likelihood of mortality for most patients.

• Major (Level 3) – High chance of mortality, usually associated with severe comorbidities or complications.

• Extreme (Level 4) – Very high likelihood of mortality, often in critically ill patients with multiple organ failure or advanced disease.

Why is ROM Important in Coding?

ROM plays a critical role in healthcare data and reimbursement. It is not only a measure of patient acuity but also a quality indicator that helps hospitals, payers, and regulators understand the severity of the cases being treated.

Key impacts of ROM include:

• Hospital Benchmarking: ROM is used to compare mortality rates across hospitals while adjusting for patient complexity.

• Quality Reporting: Regulatory bodies, such as CMS, monitor ROM to assess hospital performance.

• Reimbursement: Higher ROM levels often reflect more complex care and can influence DRG assignment and payment levels.

• Risk Adjustment: Helps ensure fair comparisons between facilities that treat different types of patients.

Coding and Documentation Considerations

Accurate ROM assignment depends heavily on complete and specific provider documentation. Coders should carefully review:

• Principal Diagnosis: The main condition prompting admission.

• Secondary Diagnoses: Comorbidities and complications (CCs/MCCs) that increase severity and impact ROM.

• Procedures: Certain interventions (like mechanical ventilation) significantly raise ROM.

• Clinical Indicators: Lab results, imaging findings, and physician statements that justify higher severity levels.

Common Documentation Issues:

• Missing specificity – e.g., documenting “heart failure” without stating systolic/diastolic or acute/chronic.

• Underreporting comorbidities – failing to capture all active conditions being monitored and treated.

• Overgeneralized terms – vague terms like “respiratory distress” instead of specific diagnoses such as “acute hypoxemic respiratory failure.”

Best Practices for Coders

• Query physicians when documentation lacks specificity to ensure accurate reflection of severity.

• Capture all CCs and MCCs that impact patient care and resource use.

• Stay current on coding guidelines since updates can affect DRG, SOI (Severity of Illness), and ROM assignment.

• Work with CDI (Clinical Documentation Integrity) specialists to improve accuracy of coded data.

ROM vs. SOI (Severity of Illness)

While ROM estimates the likelihood of death, SOI reflects how sick the patient is overall and how much care they require. Both are measured on the same 4-level scale (minor, moderate, major, extreme). While SOI measures how sick a patient is, ROM specifically quantifies the probability of a patient dying during their hospitalization. 

• Example: A patient may have a high SOI (requiring extensive resources) but a moderate ROM (not at high risk of death).

• Accurate coding ensures both SOI and ROM are properly captured, giving a complete picture of the patient’s condition.\

Risk of Mortality (ROM) is a key metric in medical coding that directly affects hospital reporting, reimbursement, and patient outcome data. Coders play an essential role in ensuring that ROM is accurately reflected by capturing the most precise diagnoses, comorbidities, and clinical indicators.

Improved documentation and coding practices not only support correct payment but also ensure hospitals are fairly measured against their peers in terms of quality of care.

ACDIS https://acdis.org/articles/qa-understanding-soi-and-rom-apr-drg-system

Coding Clarified SOI https://codingclarified.com/medical-coding-understanding-severity-of-illness-soi/