In MS-DRG logic, what does ROM indicate and how does it relate to DRG classification?

• A. ROM is a measure of patient age and has no impact on DRG.
• B. ROM stands for Risk of Mortality and has no impact on DRG.
• C. ROM stands for Readiness of Medical Care and affects only billing.
• D. SOI reflects patient severity; ROM reflects expected mortality; together they influence DRG assignment and reimbursement under MS-DRG.

Answer: (D)

In MS-DRG logic, ROM stands for Risk of Mortality, one of two acuity dimensions used alongside Severity of Illness (SOI). SOI describes how severely ill the patient is overall, while ROM estimates the likelihood of death during the hospitalization based on the patient’s diagnoses and clinical status. Together, these measures help the MS-DRG system refine classification within the same base DRG and determine the appropriate payment weight. A higher ROM or higher SOI signals greater patient complexity and resource use, which can shift a case to a higher-weighted MS-DRG, affecting reimbursement accordingly. This is why ROM is relevant to DRG classification and reimbursement under MS-DRG.