Medicare Reimbursement Systems
Understanding Medicare reimbursement systems is critical for RHIA professionals because coding, documentation, and HIM operations directly influence payment accuracy and compliance. Medicare uses multiple prospective payment systems (PPS), each tailored to a specific care setting. This topic covers the major payment systems, their components, and the role of HIM in ensuring proper reimbursement.
Prospective Payment System Overview
A prospective payment system (PPS) establishes payment rates in advance based on a classification system rather than on the actual costs of services provided. PPS was introduced to control healthcare costs by incentivizing efficiency. Under PPS, if the cost of care is less than the payment, the provider retains the difference; if costs exceed the payment, the provider absorbs the loss.
Inpatient Prospective Payment System (IPPS) and MS-DRGs
The IPPS is the payment system for acute care inpatient hospital stays. It uses Medicare Severity Diagnosis Related Groups (MS-DRGs) as its classification system.
How MS-DRGs work:
- Every inpatient discharge is assigned to one of approximately 760 MS-DRGs based on the principal diagnosis, secondary diagnoses (particularly complications and comorbidities), procedures performed, age, sex, and discharge status.
- Each MS-DRG has a relative weight reflecting the average resource consumption for that group relative to the average Medicare case.
- Payment is calculated by multiplying the MS-DRG relative weight by the hospital's base rate, which is adjusted for geographic wage differences using the wage index.
CC and MCC classification:
| Category | Description | Impact |
|---|---|---|
| MCC (Major Complication/Comorbidity) | A diagnosis that has a significant effect on resource consumption | Assigns the case to the highest-weighted MS-DRG in the group |
| CC (Complication/Comorbidity) | A diagnosis that has a moderate effect on resource consumption | Assigns the case to a mid-level MS-DRG |
| Non-CC | A diagnosis that does not significantly affect resource consumption | Assigns the case to the base (lowest-weighted) MS-DRG |
Key IPPS adjustments:
- Outlier payments: Additional payment for cases with extraordinarily high costs that exceed a threshold above the DRG payment.
- Transfer policy: When a patient is transferred to another acute care hospital before completing the full DRG stay, the transferring hospital receives a per diem payment rather than the full DRG payment.
- Disproportionate Share Hospital (DSH) adjustment: Additional payment for hospitals that serve a disproportionately large share of low-income patients.
- Indirect Medical Education (IME) adjustment: Additional payment for teaching hospitals to account for higher costs associated with training residents.
Outpatient Prospective Payment System (OPPS)
The OPPS covers hospital outpatient services, including emergency department visits, observation services, outpatient surgeries, and clinic visits. It uses Ambulatory Payment Classifications (APCs).
- Each service is assigned to an APC based on the HCPCS/CPT code.
- Multiple APCs can be assigned per encounter (unlike DRGs, which assign one group per stay).
- Packaging rules bundle certain ancillary services into the payment for the primary procedure.
- Status indicators determine how each HCPCS code is paid under OPPS (separately payable, packaged, not payable, etc.).
Other Medicare Payment Systems
| Setting | Payment System | Classification Unit |
|---|---|---|
| Skilled Nursing Facilities (SNF) | SNF PPS | Patient Driven Payment Model (PDPM) - uses case-mix groups based on clinical characteristics, not therapy minutes |
| Home Health Agencies | Home Health PPS | Patient-Driven Groupings Model (PDGM) - uses clinical groupings, functional levels, and comorbidity adjustments |
| Inpatient Rehabilitation Facilities (IRF) | IRF PPS | Case-Mix Groups (CMGs) - based on impairment category, functional status, age, and comorbidities |
| Long-Term Care Hospitals (LTCH) | LTCH PPS | MS-LTC-DRGs - similar to MS-DRGs but with weights specific to long-term care |
| Inpatient Psychiatric Facilities (IPF) | IPF PPS | Per diem payment adjusted for DRG, comorbidities, age, and facility characteristics |
| Physician Services | Medicare Physician Fee Schedule (MPFS) | Resource-Based Relative Value Scale (RBRVS) - RVUs for work, practice expense, and malpractice multiplied by a conversion factor |
| Ambulatory Surgical Centers (ASC) | ASC Payment System | APC-based payment groups specific to the ASC setting |
Value-Based Payment Programs
Medicare has increasingly moved toward value-based reimbursement models that tie payment to quality outcomes:
- Hospital Value-Based Purchasing (VBP): Adjusts IPPS payments based on hospital performance on clinical outcomes, patient experience, safety, and efficiency measures.
- Hospital Readmissions Reduction Program (HRRP): Reduces payments to hospitals with excess readmissions for specified conditions.
- Hospital-Acquired Condition (HAC) Reduction Program: Penalizes hospitals in the bottom quartile for hospital-acquired condition rates.
- Merit-Based Incentive Payment System (MIPS): Adjusts physician payments based on quality, promoting interoperability, improvement activities, and cost measures.
The Role of HIM in Reimbursement
HIM professionals directly influence reimbursement through:
- Accurate and compliant coding that properly reflects the patient's clinical conditions and services provided.
- Clinical documentation improvement (CDI) programs that ensure documentation supports the severity of illness and risk of mortality.
- Charge capture and charge description master (CDM) maintenance.
- Denial management and appeals for improperly denied claims.
- Monitoring coding accuracy metrics and DRG distribution patterns.
Exam Preparation Tips
For the RHIA exam, know which payment system applies to each care setting. Understand how MS-DRGs are calculated and the impact of CCs and MCCs on payment. Be familiar with the distinction between IPPS and OPPS (one DRG per stay vs. multiple APCs per encounter). Know the key value-based programs and their penalties. Questions frequently present a scenario and ask you to identify which payment system or classification applies.