Risk Adjustment

Risk Adjustment — Pipeline Skill

Overview

Provide deterministic, copy-paste-ready Python and SQL code for CMS-HCC risk adjustment: ICD-10-to-HCC crosswalk, hierarchy resolution, RAF score calculation, and coding gap identification from Rx/lab proxies.

Usage

• Apply ICD-10-to-HCC crosswalk and resolve disease hierarchies programmatically
• Calculate member-level RAF scores and identify coding gaps from Rx/lab proxies

Core Concepts

Response Format

• Lead with the command or code the user needs — explain after
• Structure as: confirm inputs → working code → key parameters explained → gotchas
• One complete working example per task; do not show every alternative
• Keep code comments minimal and functional (what, not why-it-exists)
• Target: 50-100 lines of code with brief surrounding explanation

1. ICD-10-to-HCC Crosswalk

Python

import pandas as pd


def load_crosswalk(filepath: str) -> pd.DataFrame:
    """Load CMS ICD-10-to-CC crosswalk. Expected columns: [icd10, cc]."""
    xwalk = pd.read_csv(filepath, dtype=str)
    xwalk.columns = [c.strip().lower() for c in xwalk.columns]
    xwalk["icd10"] = xwalk["icd10"].str.replace(".", "", regex=False).str.upper()
    xwalk["cc"] = xwalk["cc"].astype(int)
    return xwalk


def map_diagnoses_to_ccs(dx_df: pd.DataFrame, xwalk: pd.DataFrame) -> pd.DataFrame:
    """Map member diagnoses to Condition Categories.

    Args:
        dx_df: [member_id, icd10, service_date, provider_type].
        xwalk: [icd10, cc].
    Returns:
        Deduplicated [member_id, icd10, cc].
    """
    dx = dx_df.copy()
    dx["icd10"] = dx["icd10"].str.replace(".", "", regex=False).str.upper()
    qualifying = {"MD", "DO", "NP", "PA", "CNS"}
    dx = dx[dx["provider_type"].str.upper().isin(qualifying)]
    mapped = dx.merge(xwalk, on="icd10", how="inner")
    return mapped.drop_duplicates(subset=["member_id", "cc"])

SQL

SELECT DISTINCT d.member_id, d.icd10, x.cc
FROM diagnoses d
JOIN icd10_cc_crosswalk x ON REPLACE(d.icd10, '.', '') = x.icd10
WHERE d.provider_type IN ('MD','DO','NP','PA','CNS')
  AND d.service_date BETWEEN '2025-01-01' AND '2025-12-31';

2. Hierarchy Resolution

Python

import pandas as pd
from collections import defaultdict

# V24 hierarchies: {higher_cc: [lower_ccs_it_supersedes]}
V24_HIERARCHIES = {
    17: [18, 19], 18: [19],           # Diabetes
    85: [86, 87], 86: [87],           # Heart failure
    111: [112],                        # COPD > asthma
    136: [137, 138], 137: [138],      # Renal
    8: [9,10,11,12], 9: [10,11,12], 10: [11,12], 11: [12],  # Cancer
    107: [108],                        # Vascular
    27: [28, 29], 28: [29],           # Liver
    51: [52],                          # Dementia
    82: [83, 84], 83: [84],           # Hemiplegia
}


def resolve_hierarchies(member_ccs: pd.DataFrame,
                        hierarchies: dict = None) -> pd.DataFrame:
    """Remove lower CCs when higher CC in same hierarchy is present.

    Args:
        member_ccs: [member_id, cc].
        hierarchies: {higher_cc: [lower_ccs]}. Defaults to V24.
    Returns:
        [member_id, hcc] with only surviving CCs.
    """
    if hierarchies is None:
        hierarchies = V24_HIERARCHIES

    superseded_by = defaultdict(set)
    for higher, lowers in hierarchies.items():
        for lower in lowers:
            superseded_by[lower].add(higher)

    results = []
    for mid, grp in member_ccs.groupby("member_id"):
        cc_set = set(grp["cc"])
        for cc in cc_set:
            if not superseded_by.get(cc, set()).intersection(cc_set):
                results.append({"member_id": mid, "hcc": cc})
    return pd.DataFrame(results)

SQL

WITH hierarchy_rules AS (
    SELECT 17 AS hi, 18 AS lo UNION ALL SELECT 17,19 UNION ALL SELECT 18,19 UNION ALL
    SELECT 85,86 UNION ALL SELECT 85,87 UNION ALL SELECT 86,87 UNION ALL
    SELECT 111,112 UNION ALL SELECT 136,137 UNION ALL SELECT 136,138 UNION ALL SELECT 137,138
),
superseded AS (
    SELECT mc.member_id, mc.cc
    FROM member_ccs mc
    JOIN hierarchy_rules h ON mc.cc = h.lo
    JOIN member_ccs mc2 ON mc.member_id = mc2.member_id AND mc2.cc = h.hi
)
SELECT mc.member_id, mc.cc AS hcc
FROM member_ccs mc
LEFT JOIN superseded s ON mc.member_id = s.member_id AND mc.cc = s.cc
WHERE s.cc IS NULL;

3. RAF Score Calculation

import pandas as pd

# V24 Community Non-Dual Aged (example subset)
DEMO_COEFF = {
    ("M","65-69"): 0.395, ("M","70-74"): 0.487, ("M","75-79"): 0.596,
    ("M","80-84"): 0.728, ("M","85-89"): 0.896, ("M","90-94"): 1.003, ("M","95+"): 1.073,
    ("F","65-69"): 0.339, ("F","70-74"): 0.421, ("F","75-79"): 0.532,
    ("F","80-84"): 0.668, ("F","85-89"): 0.854, ("F","90-94"): 0.979, ("F","95+"): 1.055,
}

HCC_COEFF = {
    8: 2.484, 9: 0.975, 10: 0.690, 17: 0.368, 18: 0.368, 19: 0.118,
    47: 0.545, 51: 0.437, 52: 0.294, 85: 0.441, 86: 0.335, 87: 0.237,
    96: 0.296, 111: 0.335, 112: 0.199, 136: 0.288, 137: 0.237, 138: 0.237,
}

INTERACTIONS = {
    frozenset(["diabetes","chf"]): 0.154,
    frozenset(["chf","copd"]): 0.175,
    frozenset(["chf","renal"]): 0.154,
    frozenset(["diabetes","chf","copd"]): 0.047,
}

HCC_GROUP = {
    17: "diabetes", 18: "diabetes", 85: "chf", 86: "chf",
    111: "copd", 112: "copd", 136: "renal", 137: "renal", 138: "renal",
}


def calculate_raf(demographics: pd.DataFrame, member_hccs: pd.DataFrame) -> pd.DataFrame:
    """Calculate RAF scores. demographics: [member_id, sex, age_group]. member_hccs: [member_id, hcc]."""
    hcc_map = member_hccs.groupby("member_id")["hcc"].apply(set).to_dict()
    rows = []
    for _, r in demographics.iterrows():
        mid, hccs = r["member_id"], hcc_map.get(r["member_id"], set())
        demo = DEMO_COEFF.get((r["sex"], r["age_group"]), 0.0)
        hcc_score = sum(HCC_COEFF.get(h, 0.0) for h in hccs)
        groups = {HCC_GROUP[h] for h in hccs if h in HCC_GROUP}
        interact = sum(v for k, v in INTERACTIONS.items() if k.issubset(groups))
        rows.append({"member_id": mid, "demo": round(demo, 3), "hcc_score": round(hcc_score, 3),
                      "interaction": round(interact, 3), "total_raf": round(demo + hcc_score + interact, 3),
                      "hcc_count": len(hccs), "hccs": sorted(hccs)})
    return pd.DataFrame(rows).sort_values("total_raf", ascending=False)

SQL

WITH hcc_scores AS (
    SELECT mh.member_id, SUM(c.coefficient) AS hcc_score, COUNT(*) AS hcc_count
    FROM member_hccs mh
    JOIN hcc_coefficients c ON mh.hcc = c.hcc
    WHERE c.model_version = 'V24' AND c.segment = 'CNA'
    GROUP BY mh.member_id
),
demo_scores AS (
    SELECT md.member_id, dc.coefficient AS demo_score
    FROM member_demographics md
    JOIN demographic_coefficients dc ON md.sex = dc.sex AND md.age_group = dc.age_group
    WHERE dc.model_version = 'V24' AND dc.segment = 'CNA'
)
SELECT d.member_id, d.demo_score, COALESCE(h.hcc_score, 0) AS hcc_score,
       ROUND(d.demo_score + COALESCE(h.hcc_score, 0), 3) AS total_raf
FROM demo_scores d LEFT JOIN hcc_scores h ON d.member_id = h.member_id
ORDER BY total_raf DESC;

4. Coding Gap Identification

4a. Rx Proxy Gaps

import pandas as pd

RX_MAP = {
    "metformin":      {"condition": "diabetes",       "icd_pfx": "E11", "hccs": [17,18,19]},
    "glipizide":      {"condition": "diabetes",       "icd_pfx": "E11", "hccs": [17,18,19]},
    "insulin":        {"condition": "diabetes",       "icd_pfx": "E11", "hccs": [17,18,19]},
    "furosemide":     {"condition": "heart_failure",  "icd_pfx": "I50", "hccs": [85,86,87]},
    "spironolactone": {"condition": "heart_failure",  "icd_pfx": "I50", "hccs": [85,86,87]},
    "albuterol":      {"condition": "copd_asthma",    "icd_pfx": "J44", "hccs": [111,112]},
    "donepezil":      {"condition": "dementia",       "icd_pfx": "F03", "hccs": [51,52]},
    "memantine":      {"condition": "dementia",       "icd_pfx": "F03", "hccs": [51,52]},
}


def identify_rx_gaps(rx_df: pd.DataFrame, dx_df: pd.DataFrame, year: int) -> pd.DataFrame:
    """Members with Rx evidence but no matching diagnosis in payment year."""
    rx_yr = rx_df[rx_df["fill_date"].dt.year == year]
    dx_yr = dx_df[dx_df["service_date"].dt.year == year].copy()
    dx_yr["pfx"] = dx_yr["icd10"].str[:3]

    gaps = []
    for drug, m in RX_MAP.items():
        with_rx = set(rx_yr[rx_yr["drug_name"].str.lower().str.contains(drug, na=False)]["member_id"])
        with_dx = set(dx_yr[dx_yr["pfx"] == m["icd_pfx"]]["member_id"])
        for mid in with_rx - with_dx:
            gaps.append({"member_id": mid, "condition": m["condition"],
                         "evidence": drug, "target_hccs": m["hccs"], "gap_type": "rx_proxy"})
    return pd.DataFrame(gaps).drop_duplicates(subset=["member_id", "condition"])

4b. Lab Proxy Gaps

import pandas as pd

LAB_MAP = {
    "HbA1c": {"thresh": 6.5, "op": ">=", "condition": "diabetes",       "icd_pfx": "E11", "hccs": [17,18,19]},
    "eGFR":  {"thresh": 60,  "op": "<",  "condition": "ckd",            "icd_pfx": "N18", "hccs": [136,137,138]},
    "BNP":   {"thresh": 100, "op": ">=", "condition": "heart_failure",  "icd_pfx": "I50", "hccs": [85,86,87]},
    "BMI":   {"thresh": 40,  "op": ">=", "condition": "morbid_obesity", "icd_pfx": "E66", "hccs": [22]},
}


def identify_lab_gaps(labs: pd.DataFrame, dx_df: pd.DataFrame, year: int) -> pd.DataFrame:
    """Members with abnormal labs but no matching diagnosis."""
    labs_yr = labs[labs["result_date"].dt.year == year]
    dx_yr = dx_df[dx_df["service_date"].dt.year == year].copy()
    dx_yr["pfx"] = dx_yr["icd10"].str[:3]

    gaps = []
    for test, m in LAB_MAP.items():
        t = labs_yr[labs_yr["test_name"].str.upper() == test.upper()].copy()
        t["val"] = pd.to_numeric(t["result_value"], errors="coerce")
        abn = t[t["val"] >= m["thresh"]] if m["op"] == ">=" else t[t["val"] < m["thresh"]]
        with_dx = set(dx_yr[dx_yr["pfx"] == m["icd_pfx"]]["member_id"])
        for mid in set(abn["member_id"]) - with_dx:
            gaps.append({"member_id": mid, "condition": m["condition"],
                         "evidence": test, "target_hccs": m["hccs"], "gap_type": "lab_proxy"})
    return pd.DataFrame(gaps).drop_duplicates(subset=["member_id", "condition"])

SQL — Rx Gap Detection

WITH rx_diabetes AS (
    SELECT DISTINCT member_id FROM rx_claims
    WHERE LOWER(drug_name) IN ('metformin','glipizide','insulin glargine','insulin lispro')
      AND fill_date BETWEEN '2025-01-01' AND '2025-12-31'
),
dx_diabetes AS (
    SELECT DISTINCT member_id FROM diagnoses
    WHERE icd10 LIKE 'E11%' AND service_date BETWEEN '2025-01-01' AND '2025-12-31'
      AND provider_type IN ('MD','DO','NP','PA')
)
SELECT r.member_id, 'diabetes' AS condition, 'rx_proxy' AS gap_type
FROM rx_diabetes r LEFT JOIN dx_diabetes d ON r.member_id = d.member_id
WHERE d.member_id IS NULL;

5. End-to-End Pipeline

def project_risk_scores(dx_df, xwalk_df, demo_df, hierarchies=None):
    """Full pipeline: crosswalk → hierarchy → RAF → summary."""
    ccs = map_diagnoses_to_ccs(dx_df, xwalk_df)
    hccs = resolve_hierarchies(ccs, hierarchies)
    scores = calculate_raf(demo_df, hccs)
    print(f"Members: {len(scores)}, Mean RAF: {scores['total_raf'].mean():.3f}, "
          f"Median: {scores['total_raf'].median():.3f}")
    return scores

6. Parameter Reference

Common Mistakes

• Wrong: Applying the ICD-10-to-HCC crosswalk without stripping periods from ICD-10 codes Right: Normalize codes with str.replace(".", "").upper() before joining to the crosswalk Why: CMS crosswalk files use unformatted codes (e.g., E119 not E11.9); mismatches silently drop valid mappings

• Wrong: Summing all CC coefficients without running hierarchy resolution first Right: Always call resolve_hierarchies() to retain only the highest-severity CC per hierarchy group before scoring Why: Counting superseded CCs inflates RAF scores and produces incorrect revenue projections

• Wrong: Using V24 hierarchies and coefficients for payment year 2026+ Right: Use V28 tables for PY 2026+; use blended weights (33% V24 / 67% V28) for PY 2025 Why: CMS transitions to V28 full-weight in 2026; stale coefficients produce materially wrong scores

• Wrong: Including diagnoses from any provider type in the crosswalk mapping Right: Filter to qualifying provider types (MD, DO, NP, PA, CNS) before mapping Why: CMS only accepts diagnoses from face-to-face encounters with eligible providers for risk adjustment

• Wrong: Treating Rx proxy gaps as confirmed diagnoses and coding them directly Right: Use Rx/lab proxies to identify suspected gaps that require provider documentation on a qualifying encounter Why: Proxies are screening signals, not diagnosis sources — submitting without documentation fails RADV audit

• Wrong: Running identify_lab_gaps without converting result_value to numeric first Right: Cast with pd.to_numeric(errors="coerce") and handle NaN before threshold comparison Why: Lab values often contain text qualifiers (">100", "see note"); string comparison produces wrong results