Patient Stratification Engine

Methodology

Step 1: Clinical Complexity Scoring

Calculate disease burden and clinical complexity:

HCC (Hierarchical Condition Category) Risk Score:

• Map active ICD-10 diagnoses to HCC categories
• Calculate CMS-HCC risk adjustment factor (RAF)
• Benchmark against population average (1.0)
• Higher RAF = higher predicted cost and clinical complexity

Charlson Comorbidity Index (CCI):

• Score comorbidities: MI, CHF, PVD, CVD, dementia, COPD, connective tissue disease, PUD, liver disease, diabetes, hemiplegia, CKD, cancer, AIDS
• Each condition scores 1-6 based on severity
• Total CCI predicts 10-year mortality risk

Elixhauser Comorbidity Measure:

• 31 comorbidity categories beyond Charlson
• Captures conditions like depression, obesity, drug abuse, psychoses
• Better predictor for in-hospital mortality and LOS

Step 2: Utilization Pattern Analysis

Evaluate healthcare utilization intensity:

Step 3: Social Risk Assessment

Evaluate social determinants that amplify clinical risk:

SDOH Risk Factors (scored 0-2 each):

• Housing instability or homelessness (0=stable, 1=at risk, 2=unstable)
• Food insecurity (0=secure, 1=low security, 2=very low)
• Transportation barriers (0=none, 1=occasional, 2=frequent)
• Social isolation (0=connected, 1=limited, 2=isolated)
• Health literacy (0=adequate, 1=limited, 2=low)
• Financial strain (0=stable, 1=some stress, 2=severe)

Total SDOH score: 0-12 (Low: 0-3, Moderate: 4-7, High: 8-12)

Step 4: Composite Risk Tier Assignment

Combine clinical, utilization, and social scores into a composite tier:

Step 5: Actionable Segmentation

Assign patients to intervention programs based on tier and dominant risk drivers:

Tier-Based Program Mapping:

• Tier 1: Preventive outreach, annual wellness visits, gap closure
• Tier 2: Chronic disease education, medication management, care gap alerts
• Tier 3: Assigned care manager, regular check-ins, transition management
• Tier 4: Intensive care team (RN + SW + pharmacist + CHW), home visits, high-touch coordination

Output Specification

The output includes:

patient_profile: demographics, insurance, pcp assignment

clinical_complexity: hcc_raf_score, charlson_cci, active_conditions_count, medication_count, high_risk_conditions list

utilization_profile: ed_visits_12mo, admissions_12mo, readmissions, specialist_count, total_cost_of_care, cost_percentile

sdoh_assessment: individual factor scores, total_sdoh_score, sdoh_risk_level

composite_stratification: risk_tier (1-4), tier_label, composite_score, dominant_risk_domain, confidence_level

intervention_assignment: program_name, intervention_level, recommended_team_composition, key_focus_areas, engagement_frequency

rising_risk_indicators: flags for patients trending toward higher tier (increasing utilization, new diagnoses, SDOH changes)

Analysis Framework

Impactability Assessment

Not all high-risk patients are equally impactable. Assess:

1. Modifiable risk factors present: Can interventions change the trajectory?
2. Patient engagement likelihood: History of appointment adherence, responsiveness
3. Intervention availability: Are appropriate programs and resources available?
4. Cost-effectiveness: Will intervention costs be offset by utilization reduction?

Impactability Score: High (good candidate for intensive program), Medium (moderate intervention), Low (maintain monitoring, fewer modifiable factors)

Trend Analysis

Track tier movement over time:

• Improving: Moving to lower risk tier (intervention success indicator)
• Stable: Remaining in same tier (maintenance mode)
• Worsening: Moving to higher tier (intervention escalation needed)
• Rising risk: Not yet high tier but trending upward (early intervention opportunity)

Examples

Input: 72-year-old male, CHF (EF 35%), DM2 with neuropathy, CKD Stage 3a, depression. On 12 medications. 3 ED visits in 12 months, 2 hospital admissions (1 readmission). Lives alone in rural area. Limited transportation. Income below 200% FPL.

Stratification:

• Clinical: HCC-RAF 2.4 (high), CCI 6 (high), 4 active chronic conditions, polypharmacy
• Utilization: 3 ED, 2 admits, 1 readmission — HIGH
• SDOH: Social isolation (2) + transportation (2) + financial (2) = 6/12 — MODERATE
• Composite: Tier 4 - Complex/Very High
• Dominant driver: Clinical complexity + utilization intensity
• Recommended: Intensive care management team with home health, telemonitoring, community health worker for transportation, pharmacist for medication management

Guidelines

1. Stratification is dynamic — reassess at least quarterly or after significant clinical events
2. Avoid label bias — risk tiers inform resource allocation, not patient worth
3. Include rising-risk identification — intervening before patients become high-risk is most cost-effective
4. Validate models against outcomes — regularly calibrate stratification against actual utilization and costs
5. Ensure equity — audit stratification for demographic bias and disparities

Validation Checklist

• All data inputs are current (within 90 days for clinical, 12 months for utilization)
• HCC coding is complete and accurate (capture all relevant conditions)
• SDOH assessment is completed (not defaulted to zero/unknown)
• Composite tier assignment reflects the dominant risk driver
• Intervention assignments match available program capacity
• Rising-risk indicators are flagged for proactive intervention
• Stratification model is calibrated against actual outcomes

HIPAA Compliance Notes

• Risk stratification data aggregates extensive PHI and requires strict access controls
• Share stratification results only with care team members with a need to know
• De-identify population-level stratification reports for quality improvement
• SDOH data may have additional privacy requirements under state law
• Patient consent should be obtained before enrolling in care management programs based on stratification
• Maintain audit logs for all stratification data access and sharing