feat: add drug-to-indication mapping from DimSearchTerm.csv (Task 1.2)

Add load_drug_indication_mapping() and get_search_terms_for_drug() to
diagnosis_lookup.py. Loads DimSearchTerm.csv to build bidirectional
lookup between drug name fragments and Search_Terms. Uses substring
matching for drug fragments (handles both exact names like ADALIMUMAB
and partial fragments like PEGYLATED). Handles duplicate Search_Terms
(e.g., diabetes appearing under two directorates) by combining fragments.
This commit is contained in:
Andrew Charlwood
2026-02-05 22:48:09 +00:00
parent 1c4d2c07ee
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# Implementation Plan - Indication-Based Pathway Charts
# Implementation Plan - Drug-Aware Indication Matching
## Project Overview
Extend the pathway analysis application to show indication-based icicle charts alongside directory-based charts. Patient diagnoses are matched from GP records using SNOMED cluster codes.
Update the indication-based pathway charts so that patient indications are matched **per drug**, not just per patient. Currently, each patient gets ONE indication (most recent GP diagnosis match). This ignores which drugs the patient is actually taking.
### The Problem
A patient on ADALIMUMAB + OMALIZUMAB currently gets assigned a single indication (e.g., "rheumatoid arthritis" — the most recent GP match). But:
- ADALIMUMAB is used for rheumatoid arthritis, axial spondyloarthritis, crohn's disease, etc.
- OMALIZUMAB is used for asthma, allergic asthma, urticaria
These are different clinical pathways and should be treated as separate treatment journeys.
### The Solution
Match each drug to an indication by cross-referencing:
1. **GP diagnosis** — which Search_Terms the patient has matching SNOMED codes for
2. **Drug mapping** — which Search_Terms list each drug (from `DimSearchTerm.csv`)
Only assign a drug to an indication if BOTH conditions are met. If a patient's drugs map to different indications, they become separate pathways (via modified UPID).
### Key Design Decisions
| Aspect | Decision |
|--------|----------|
| SNOMED source | Query `ClinicalCodingClusterSnomedCodes` clusters directly in Snowflake |
| Grouping level | `Search_Term` from cluster mapping (~148 conditions) |
| Chart types | Two: "By Directory" (existing) and "By Indication" (new toggle) |
| No-match display | Show assigned directorate in indication chart (mixed labels) |
| Multiple matches | Use most recent SNOMED code by GP record date |
| Data storage | No local SNOMED mapping — query Snowflake at refresh time |
| Drug-indication source | `data/DimSearchTerm.csv` — Search_Term → CleanedDrugName mapping |
| UPID modification | `{original_UPID}\|{search_term}` for drugs with matched indication |
| GP diagnosis matching | Return ALL matches per patient (not just most recent) |
| Drug matching | Substring match: HCD drug name contains DimSearchTerm fragment |
| Multiple indication matches per drug | Use highest GP code frequency as tiebreaker (COUNT of matching SNOMED codes per Search_Term) |
| GP code time range | Only codes from MIN(Intervention Date) onwards — restricts to HCD data window |
| No indication match | Fallback to directory (same as current behavior) |
| Same patient, different indications | Separate pathways via different modified UPIDs |
### SNOMED Cluster Query
The `snomed_indication_mapping_query.sql` file contains the master query:
- Maps Search_Term → Cluster_ID for ~148 conditions
- Joins `ClinicalCodingClusterSnomedCodes` to get SNOMED codes per cluster
- Includes explicit manual mappings for conditions not in clusters
- Returns: Search_Term, SNOMEDCode, SNOMEDDescription
### Examples
## Quality Checks
**Patient on ADALIMUMAB + GOLIMUMAB, GP dx: axial spondyloarthritis + asthma**
- axial spondyloarthritis drug list includes both ADALIMUMAB and GOLIMUMAB
- → Both drugs grouped under "axial spondyloarthritis", single pathway
- Modified UPID: `RMV12345|axial spondyloarthritis`
Run after each task:
**Patient on ADALIMUMAB + OMALIZUMAB, GP dx: axial spondyloarthritis + asthma**
- axial spondyloarthritis lists ADALIMUMAB but not OMALIZUMAB
- asthma lists OMALIZUMAB but not ADALIMUMAB
- → Two separate pathways:
- `RMV12345|axial spondyloarthritis` with ADALIMUMAB
- `RMV12345|asthma` with OMALIZUMAB
```bash
# Syntax check
python -m py_compile <modified_file.py>
# Import verification
python -c "from data_processing.diagnosis_lookup import *"
python -c "from data_processing.pathway_pipeline import *"
# For Reflex changes
python -m reflex compile
```
**Patient on ADALIMUMAB, GP dx: rheumatoid arthritis (47 codes) + crohn's disease (2 codes)**
- Both Search_Terms list ADALIMUMAB AND patient has GP dx for both
- → Tiebreaker: highest code frequency — rheumatoid arthritis has 47 matching SNOMED codes vs 2 for crohn's
- → Single pathway under rheumatoid arthritis (more clinical activity = more likely the treatment indication)
---
## Phase 1: Snowflake Integration
## Phase 1: Update Snowflake Query & Drug Mapping
### 1.1 Create Indication Lookup Query
- [x] Add `get_patient_indication_groups()` function to `data_processing/diagnosis_lookup.py`:
- Takes: list of patient pseudonyms (PseudoNHSNoLinked values)
- Uses the cluster query from `snomed_indication_mapping_query.sql` as a CTE
- Joins with `PrimaryCareClinicalCoding` to find patients with matching diagnoses
- Returns: DataFrame with PatientPseudonym, Search_Term, EventDateTime
- Uses most recent match per patient (ORDER BY EventDateTime DESC)
- [x] Handle edge cases: Snowflake unavailable, empty patient list
- [x] Verify: Function returns expected Search_Terms for test patients (92.8% match rate, 139 unique Search_Terms)
### 1.1 Update `get_patient_indication_groups()` to return ALL matches with frequency
- [ ] Modify the Snowflake query in `get_patient_indication_groups()` (diagnosis_lookup.py):
- Remove `QUALIFY ROW_NUMBER() OVER (PARTITION BY ... ORDER BY EventDateTime DESC) = 1`
- Return ALL matching Search_Terms per patient with code frequency:
```sql
SELECT pc."PatientPseudonym" AS "PatientPseudonym",
aic.Search_Term AS "Search_Term",
COUNT(*) AS "code_frequency"
FROM PrimaryCareClinicalCoding pc
JOIN AllIndicationCodes aic ON pc."SNOMEDCode" = aic.SNOMEDCode
WHERE pc."PatientPseudonym" IN (...)
AND pc."EventDateTime" >= :earliest_hcd_date
GROUP BY pc."PatientPseudonym", aic.Search_Term
```
- `code_frequency` = number of matching SNOMED codes per Search_Term per patient
- Higher frequency = more clinical activity = stronger signal for tiebreaker
- `earliest_hcd_date` = `MIN(Intervention Date)` from the HCD DataFrame — restricts GP codes to the HCD data window, reducing noise from old/irrelevant diagnoses
- [ ] Accept `earliest_hcd_date` parameter in `get_patient_indication_groups()` and pass to query
- [ ] Keep batch processing (500 patients per query)
- [ ] Update return type: DataFrame now has multiple rows per patient (PatientPseudonym, Search_Term, code_frequency)
- [ ] Verify: Query returns more rows than before (patients with multiple matching diagnoses)
### 1.2 Update Data Pipeline to Include Indications
- [x] Modify `cli/refresh_pathways.py` to call indication lookup during refresh:
- After fetching HCD data, extract unique PseudoNHSNoLinked values
- Call `get_patient_indication_groups()` with patient list
- Create `indication_df` mapping UPID → Indication_Group
- For patients with no GP match: Indication_Group = fallback directorate
- [x] Log coverage: X% diagnosis-matched, Y% fallback
- [x] Verify: indication_df has correct structure for pathway processing (verified via full pipeline run)
### 1.2 Build drug-to-Search_Term lookup from DimSearchTerm.csv
- [x] Add function `load_drug_indication_mapping()` to `diagnosis_lookup.py`:
- Loads `data/DimSearchTerm.csv`
- Builds dict: `drug_fragment (uppercase) → list[Search_Term]`
- Also builds reverse: `search_term → list[drug_fragments]`
- CleanedDrugName is pipe-separated (e.g., "ADALIMUMAB|GOLIMUMAB|IXEKIZUMAB")
- [x] Add function `get_search_terms_for_drug(drug_name, search_term_to_fragments) -> list[str]`:
- Returns all Search_Terms whose drug fragments are substrings of the drug name (case-insensitive)
- More practical than per-term boolean check — returns all matches at once for Phase 2 use
- [x] Verify: ADALIMUMAB matches "axial spondyloarthritis", OMALIZUMAB matches "asthma"
---
## Phase 2: Schema & Processing Updates
## Phase 2: Drug-Aware Indication Matching Logic
### 2.1 Add Chart Type Support to Schema
- [x] Add `chart_type` column to `pathway_nodes` table (ALREADY DONE)
- [x] Update UNIQUE constraint to include chart_type (ALREADY DONE)
- [x] Add indexes for chart_type filtering (ALREADY DONE)
- [x] Verify: Existing migration works correctly (tables created, 3,589 nodes inserted)
### 2.1 Create `assign_drug_indications()` function
- [ ] Add to `diagnosis_lookup.py` or `pathway_pipeline.py`:
```
def assign_drug_indications(
df: pd.DataFrame, # HCD data with UPID, Drug Name columns
gp_matches_df: pd.DataFrame, # PatientPseudonym → list of matched Search_Terms
drug_mapping: dict, # From load_drug_indication_mapping()
) -> tuple[pd.DataFrame, pd.DataFrame]:
Returns: (modified_df, indication_df)
- modified_df: HCD data with UPID replaced by {UPID}|{indication}
- indication_df: mapping modified_UPID → Search_Term
```
- [ ] Logic per UPID + Drug Name pair:
1. Get patient's GP-matched Search_Terms with code_frequency (from gp_matches_df via PseudoNHSNoLinked)
2. Get which Search_Terms include this drug (from drug_mapping)
3. Intersection = valid indications for this drug-patient pair
4. If 1 match: use it
5. If multiple matches: use highest code_frequency as tiebreaker (most GP coding activity = most likely treatment indication)
6. If 0 matches: use fallback directory
- [ ] Modify UPID in df rows: `{original_UPID}|{matched_search_term}`
- [ ] Build indication_df: `{modified_UPID}` → `Search_Term` (or fallback label)
- [ ] Verify: Function compiles, handles edge cases (no GP match, no drug match)
### 2.2 Create Indication Pathway Processing
- [x] Add `generate_icicle_chart_indication()` to `pathway_analyzer.py` (ALREADY DONE)
- [x] Add `process_indication_pathway_for_date_filter()` to `pathway_pipeline.py` (ALREADY DONE)
- [x] Add `extract_indication_fields()` for denormalized columns (ALREADY DONE)
- [x] Update `convert_to_records()` with `chart_type` parameter (ALREADY DONE)
- [x] Verify: Code compiles, imports work correctly
### 2.3 Update Refresh Command for Dual Charts
- [x] Add `--chart-type` argument: "all", "directory", "indication" (ALREADY DONE)
- [x] Update indication processing to use new `get_patient_indication_groups()`:
- Replace `batch_lookup_indication_groups()` with the new Snowflake-direct approach
- Pass indication_df to `process_indication_pathway_for_date_filter()`
- [x] Process all 6 date filters for both chart types (existing loop already handles this)
- [x] Verify: Both chart types generate pathway data (indication verified with 695 nodes for all_6mo)
### 2.2 Handle tiebreaker for multiple indication matches
- [ ] When a drug matches multiple Search_Terms AND patient has GP dx for multiple:
- Use `code_frequency` from the GP query (COUNT of matching SNOMED codes per Search_Term)
- Higher code_frequency = more clinical activity for that condition = more likely treatment indication
- E.g., patient with 47 RA codes and 2 crohn's codes → ADALIMUMAB assigned to RA
- code_frequency is already returned by the updated query in Task 1.1
- [ ] Verify: Tiebreaker logic correctly picks highest-frequency diagnosis
- [ ] Verify: Tie on frequency (rare but possible) falls back to alphabetical Search_Term for determinism
---
## Phase 3: Test Full Pipeline
## Phase 3: Pipeline Integration
### 3.1 Test Refresh with Real Data
- [x] Run `python -m cli.refresh_pathways --chart-type indication --dry-run` with Snowflake
- [x] Verify indication hierarchy: Trust → Search_Term → Drug → Pathway
- Confirmed: 695 nodes generated for all_6mo, 8 trusts, 91 unique search_terms
- [x] Verify unmatched patients show with directorate fallback label
- Confirmed: 92.7% diagnosis-matched (34,545/37,257 UPIDs), 7.3% use fallback
- [x] Document: Processing time, record counts, coverage percentages
- Processing time: ~10 minutes total (7s data fetch, ~9 min indication lookup, ~50s pathway processing)
- Record counts: 695 indication pathway nodes for all_6mo
- Coverage: 92.8% GP diagnosis match rate (34,006/36,628 patients)
- Top indications: drug misuse (8,749), influenza (6,336), diabetes (2,516), sepsis (1,991), cardiovascular disease (954)
- [x] Run full refresh with `--chart-type all` to populate database (requires non-dry-run)
- Fixed DataFrame mutation bug in prepare_data() (df.copy() added)
- Results: 3,633 total nodes (1,101 directory + 2,532 indication) across all 12 datasets
- Database populated: 3,589 nodes in pathway_nodes table
### 3.1 Update `refresh_pathways.py` indication processing
- [ ] In the `elif current_chart_type == "indication":` block:
1. Call `get_patient_indication_groups()` as before (but now returns ALL matches)
2. Load drug mapping: `drug_mapping = load_drug_indication_mapping()`
3. Call `assign_drug_indications(df, gp_matches_df, drug_mapping)`
4. Use modified_df (with indication-aware UPIDs) for pathway processing
5. Use indication_df for the indication mapping
- [ ] Pass modified_df (not original df) to `process_indication_pathway_for_date_filter()`
- [ ] Verify: Pipeline compiles, `python -m py_compile cli/refresh_pathways.py`
### 3.2 Test with dry run
- [ ] Run `python -m cli.refresh_pathways --chart-type indication --dry-run -v`
- [ ] Verify:
- Modified UPIDs appear in pipeline log (e.g., `RMV12345|rheumatoid arthritis`)
- Patient counts are reasonable (will be higher than before since same patient can appear under multiple indications)
- Drug-indication matching is logged (match rate, fallback rate)
- Pathway hierarchy shows drug-specific grouping under correct indications
---
## Phase 4: Reflex UI Updates
## Phase 4: Full Refresh & Validation
### 4.1 Add Chart Type State
- [x] Add state variables to `AppState`:
- `selected_chart_type: str = "directory"` (options: "directory", "indication")
- `chart_type_options: list[dict]` for dropdown
- [x] Add `set_chart_type()` event handler
- [x] Update `load_pathway_data()` to filter by chart_type
- [x] Verify: State changes correctly, data queries include chart_type filter
### 4.1 Full refresh with both chart types
- [ ] Run `python -m cli.refresh_pathways --chart-type all`
- [ ] Verify:
- Both chart types generate data
- Directory charts unchanged (no modified UPIDs)
- Indication charts reflect drug-aware matching
### 4.2 Add Chart Type Toggle UI
- [x] Create `chart_type_toggle()` component:
- Segmented control with pill-style buttons: "By Directory" | "By Indication"
- Placed in filter strip, first element before date filters
- [x] Wire to `set_chart_type()` handler
- [x] Verify: Toggle switches chart data, UI updates reactively (reflex compile passed)
### 4.2 Validate indication chart correctness
- [ ] Check that drugs under an indication all appear in that Search_Term's drug list
- [ ] Verify that a patient on drugs for different indications creates separate pathway branches
- [ ] Verify that drugs sharing an indication are grouped in the same pathway
- [ ] Log: patient count comparison (old vs new approach)
### 4.3 Update Chart Display for Indication Labels
- [x] Ensure icicle chart handles mixed labels:
- Search_Term labels (e.g., "rheumatoid arthritis") for matched patients
- Directorate labels (e.g., "RHEUMATOLOGY (no GP dx)") for unmatched
- Note: labels come from pathway_nodes pre-computed data, no template changes needed
- [x] Update hierarchy description (dynamic: "Trust → Directorate → ..." or "Trust → Indication → ...")
- [x] Update chart title to include chart type prefix
- [x] Verify: Chart renders correctly with both label types (reflex compile passed)
---
## Phase 5: Validation & Documentation
### 5.1 End-to-End Validation
- [x] Run full app with both chart types
- Fixed UNIQUE constraint bug: was `UNIQUE(date_filter_id, ids)`, needed `UNIQUE(date_filter_id, chart_type, ids)`
- Directory chart was missing level 0/1 nodes due to indication chart overwriting them
- Dropped and recreated pathway_nodes table, re-ran full refresh (3,633 nodes)
- Both chart types now have levels 0-5 with correct patient counts
- [x] Verify chart toggle works correctly
- Data loading tested: directory (293 nodes) and indication (695 nodes) for all_6mo
- All 12 date filter combinations generate valid icicle charts
- Root patients match between chart types (11,118 for all_6mo)
- [x] Verify filter interactions (drugs, directorates) work for both types
- Drug filter works for both chart types (ADALIMUMAB: 70 dir, 128 ind nodes)
- Directory filter works for directory charts (RHEUMATOLOGY: 86 nodes)
- Note: Directory filter returns 0 for indication charts (expected — directory column stores Search_Terms not directorate names)
- [x] Verify KPIs update correctly for both chart types
- Both show: 11,118 patients, £130.6M total cost for all_6mo
- KPIs consistent across chart types (same underlying patient data)
- [B] Test at multiple viewport sizes (BLOCKED: requires live browser — reflex run crashes on Windows due to Granian/watchfiles FileNotFoundError, environment issue not code issue. Deferred to manual testing when environment supports it.)
### 5.2 Update Documentation
- [x] Update CLAUDE.md with new architecture
- [x] Document new CLI arguments
- [x] Document chart_type toggle behavior
- [x] Update data flow diagrams
### 4.3 Validate Reflex UI
- [ ] Run `python -m reflex compile` to verify app compiles
- [ ] Verify chart type toggle still works
- [ ] Verify indication chart shows correct hierarchy
---
## Completion Criteria
All tasks marked `[x]` AND:
- [x] App compiles without errors (`reflex compile` succeeds)
- [x] Both chart types generate pathway data (12 total: 6 dates × 2 types)
- Directory: 1,101 nodes (293+329+93+105+134+147)
- Indication: 2,532 nodes (695+785+167+198+315+372)
- [x] Chart type toggle switches between Directory and Indication views
- Data layer verified: both chart types load correctly with all hierarchy levels
- [x] GP diagnosis matching works via Snowflake cluster query
- [x] Unmatched patients show in indication chart with directorate fallback label
- [x] Coverage metrics logged (% diagnosis-matched vs fallback)
- 92.7% diagnosis-matched (34,545/37,257 UPIDs)
- [x] All filters work correctly for both chart types
- Drug filter and date filter work for both. Directory filter only applies to directory charts (expected).
- [x] Performance acceptable (< 10 min full refresh, < 500ms filter change)
- Full refresh: 903 seconds (~15 min) for all 12 datasets
- SQLite query: sub-millisecond for filter changes
- [ ] App compiles without errors (`reflex compile` succeeds)
- [ ] Both chart types generate pathway data
- [ ] Indication charts show drug-specific indication matching
- [ ] Drugs under the same indication for the same patient are in one pathway
- [ ] Drugs under different indications for the same patient create separate pathways
- [ ] Fallback works for drugs with no indication match
- [ ] Full refresh completes successfully
- [ ] Existing directory charts are unaffected
---
## Reference
### SNOMED Cluster Query Structure
```sql
-- From snomed_indication_mapping_query.sql
WITH SearchTermClusters AS (
SELECT Search_Term, Cluster_ID FROM (VALUES
('rheumatoid arthritis', 'eFI2_InflammatoryArthritis'),
('macular degeneration', 'CUST_ICB_VISUAL_IMPAIRMENT'),
-- ... ~148 mappings
) AS t(Search_Term, Cluster_ID)
),
ClusterCodes AS (
SELECT stc.Search_Term, c."SNOMEDCode", c."SNOMEDDescription"
FROM SearchTermClusters stc
JOIN DATA_HUB.PHM."ClinicalCodingClusterSnomedCodes" c
ON stc.Cluster_ID = c."Cluster_ID"
WHERE c."SNOMEDCode" IS NOT NULL
),
ExplicitCodes AS (
-- Manual mappings for conditions not in clusters
SELECT Search_Term, SNOMEDCode, SNOMEDDescription FROM (VALUES
('ankylosing spondylitis', '162930007', 'Manual mapping'),
-- ...
) AS t(Search_Term, SNOMEDCode, SNOMEDDescription)
)
SELECT * FROM ClusterCodes
UNION ALL
SELECT * FROM ExplicitCodes
### DimSearchTerm.csv Structure
```
Search_Term,CleanedDrugName,PrimaryDirectorate
rheumatoid arthritis,ABATACEPT|ADALIMUMAB|ANAKINRA|BARICITINIB|...,RHEUMATOLOGY
asthma,BENRALIZUMAB|DUPILUMAB|INHALED|MEPOLIZUMAB|OMALIZUMAB|RESLIZUMAB,THORACIC MEDICINE
```
### Current Pathway Hierarchy (Directory-based)
### Modified UPID Format
```
Root (N&W ICS)
└── Trust (NNUH, QEH, JPH, etc.)
└── Directory (RHEUMATOLOGY, OPHTHALMOLOGY, etc.)
└── Drug (ADALIMUMAB, RANIBIZUMAB, etc.)
└── Pathway (drug sequences)
Original: RMV12345
Modified: RMV12345|rheumatoid arthritis
Fallback: RMV12345|RHEUMATOLOGY (no GP dx)
```
### New Pathway Hierarchy (Indication-based)
### Current vs New Indication Flow
```
Root (N&W ICS)
└── Trust (NNUH, QEH, JPH, etc.)
└── Search_Term (rheumatoid arthritis, macular degeneration, etc.)
│ OR Directorate (RHEUMATOLOGY - for unmatched patients)
└── Drug (ADALIMUMAB, RANIBIZUMAB, etc.)
└── Pathway (drug sequences)
CURRENT:
Patient → GP dx (most recent) → single Search_Term → one pathway
NEW:
Patient + Drug A → GP dx matching Drug A → Search_Term X
Patient + Drug B → GP dx matching Drug B → Search_Term Y
→ If X == Y: one pathway under X
→ If X != Y: two pathways (modified UPIDs)
```
### Key Files
| File | Purpose |
| File | Changes |
|------|---------|
| `snomed_indication_mapping_query.sql` | Master SNOMED cluster query |
| `data_processing/diagnosis_lookup.py` | GP diagnosis lookup functions |
| `data_processing/pathway_pipeline.py` | Indication pathway processing |
| `cli/refresh_pathways.py` | CLI for dual chart type refresh |
| `pathways_app/pathways_app.py` | Reflex UI with chart type toggle |
### Expected Data Volumes
| Metric | Expected |
|--------|----------|
| Search_Term conditions | ~148 (from cluster mapping) |
| Pathway nodes (directory, per date filter) | ~300 |
| Pathway nodes (indication, per date filter) | ~400-600 (more granular) |
| Total pathway nodes (6 dates × 2 types) | ~4,000-5,000 |
| `data_processing/diagnosis_lookup.py` | Update query, add drug mapping functions |
| `data_processing/pathway_pipeline.py` | Possibly minor changes for modified UPIDs |
| `cli/refresh_pathways.py` | Integrate drug-aware matching into pipeline |
| `data/DimSearchTerm.csv` | Reference data (read-only) |
| `analysis/pathway_analyzer.py` | No changes expected (UPID changes are transparent) |
| `pathways_app/pathways_app.py` | No changes expected |