HL7 PDDI-CDS Implementation Guide 技術筆記

本文件整理 HL7 Potential Drug-Drug Interaction Clinical Decision Support (PDDI-CDS) Implementation Guide 的關鍵概念，供 ThTxGNN 整合 DDI 警示功能參考。

概覽

項目 內容
全名 Potential Drug-Drug Interaction Clinical Decision Support
HL7 頁面 http://hl7.org/fhir/uv/pddi/
GitHub https://github.com/HL7/PDDI-CDS
授權 CC0-1.0（公共領域）
目的 提高 DDI 警示的臨床相關性和特異性

問題背景

現有的 PDDI 警示系統存在以下問題：

  • 過度敏感：簡單的成對藥物比較導致大量誤報
  • 警示疲勞：研究發現近乎所有 PDDI 警示都被忽略
  • 缺乏情境：未考慮病患特定條件（如腎功能、年齡）

PDDI-CDS IG 透過以下方式解決：

  1. 最小資訊模型：定義 DDI 警示必須包含的資訊元素
  2. 分級回應：根據臨床情境調整警示嚴重程度
  3. 可分享 artifacts：使用標準化的 CQL + FHIR + CDS Hooks

核心組件

1. CDS Hooks 整合

Hook 觸發時機 用途
order-select 醫師選擇藥物時 早期檢測，提供建議
order-sign 醫師簽署處方時 最終確認，提供詳細資訊

流程：

EHR → order-select hook → CDS 服務 → 檢測 PDDI → 回傳 Card
                                            ↓
                                      醫師選擇動作
                                            ↓
EHR → order-sign hook → CDS 服務 → 提供詳細建議 → 回傳 Card

2. PlanDefinition 結構

PlanDefinition 是 PDDI-CDS artifacts 的核心資源：

{
  "resourceType": "PlanDefinition",
  "id": "warfarin-nsaid-pddi",
  "type": {
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/plan-definition-type",
      "code": "eca-rule"
    }]
  },
  "trigger": [{
    "type": "named-event",
    "name": "order-select"
  }],
  "condition": [{
    "kind": "applicability",
    "expression": {
      "language": "text/cql",
      "expression": "Inclusion Criteria"
    }
  }],
  "action": [{
    "title": "Warfarin + NSAID Interaction",
    "description": "Concurrent use increases bleeding risk",
    "dynamicValue": [{
      "path": "action.description",
      "expression": {
        "language": "text/cql",
        "expression": "Get Detail"
      }
    }]
  }]
}

3. CQL 程式庫範例 

library Warfarin_NSAIDs_CDS version '1.0.0'

using FHIR version '4.0.1'
include FHIRHelpers version '4.0.1'

context Patient

// 術語定義
valueset "Warfarins": 'http://example.org/fhir/ValueSet/warfarins'
valueset "NSAIDs": 'http://example.org/fhir/ValueSet/nsaids'

// 檢測邏輯
define "Is On Warfarin":
  exists([MedicationRequest: "Warfarins"] M
    where M.status = 'active')

define "Is On NSAID":
  exists([MedicationRequest: "NSAIDs"] M
    where M.status = 'active')

define "Inclusion Criteria":
  "Is On Warfarin" and "Is On NSAID"

// 動態訊息
define "Get Detail":
  if "Has GI Risk Factors" then
    'HIGH RISK: Patient has GI risk factors. Consider alternatives.'
  else
    'MODERATE RISK: Monitor for signs of bleeding.'

4. Response Card 結構

CDS 服務回傳 CDS Hooks Card：

{
  "cards": [{
    "uuid": "warfarin-nsaid-001",
    "summary": "Potential Drug-Drug Interaction: Warfarin + NSAID",
    "detail": "Concurrent use increases bleeding risk by 3-4x.",
    "indicator": "warning",
    "source": {
      "label": "PDDI-CDS Service",
      "url": "https://example.org/pddi-cds"
    },
    "suggestions": [{
      "label": "Use alternative analgesic",
      "actions": [{
        "type": "create",
        "description": "Order acetaminophen instead",
        "resource": {
          "resourceType": "MedicationRequest",
          "medicationCodeableConcept": {
            "coding": [{"code": "161", "display": "Acetaminophen"}]
          }
        }
      }]
    }],
    "links": [{
      "label": "Warfarin-NSAID Interaction Evidence",
      "url": "https://example.org/evidence/warfarin-nsaid",
      "type": "smart"
    }]
  }]
}

5. DetectedIssue 資源

用於記錄 PDDI 檢測結果和醫師回應：

{
  "resourceType": "DetectedIssue",
  "id": "pddi-warfarin-nsaid-001",
  "status": "final",
  "code": {
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/v3-ActCode",
      "code": "DRG",
      "display": "Drug Interaction Alert"
    }]
  },
  "severity": "moderate",
  "patient": { "reference": "Patient/123" },
  "identifiedDateTime": "2026-03-01T10:00:00Z",
  "implicated": [
    { "reference": "MedicationRequest/warfarin-001" },
    { "reference": "MedicationRequest/ibuprofen-001" }
  ],
  "mitigation": [{
    "action": {
      "coding": [{
        "system": "http://terminology.hl7.org/CodeSystem/v3-ActCode",
        "code": "13",
        "display": "Stopped Concurrent Therapy"
      }]
    },
    "date": "2026-03-01T10:05:00Z",
    "author": { "reference": "Practitioner/456" }
  }]
}

實作層級

層級 要求 ThTxGNN 建議
Level 1 基本 PDDI 檢測 + DetectedIssue 儲存 目前目標
Level 2 + 情境化篩選（年齡、腎功能等） 未來擴展
Level 3 + 共同決策介面 + 替代建議 長期目標

ThTxGNN 整合方案

Phase 1：基礎警示

  1. 實作 CDS Hooks 端點
    • 支援 order-select 觸發
    • 回傳 Warning/Info Card
  2. 使用現有 DDI 資料
    • DDInter: 222,391 筆
    • GtoPdb: 4,636 筆
  3. 基本 Card 設計 
    ⚠️ DDI Warning: Warfarin + Ibuprofen
Bleeding risk increased 3-4x.
[View Evidence] [Dismiss]

Phase 2：情境化

  1. 整合病患資料
    • 年齡、腎功能、病史
    • 調整警示嚴重程度
  2. CQL 邏輯
    • 實作風險分層規則
    • 根據情境客製化訊息

Phase 3：老藥新用整合

  1. 替代建議
    • 當 DDI 發生時，建議 ThTxGNN 預測的替代藥物
  2. 共同決策
    • 提供風險/效益比較
    • 支援臨床決策

範例 DDI 規則（ThTxGNN）

Warfarin + NSAID 

library ThTxGNN_DDI_Warfarin_NSAID version '1.0.0'

using FHIR version '4.0.1'

context Patient

// 定義
define "Is On Warfarin":
  exists([MedicationRequest] M
    where M.status = 'active'
    and M.medication.coding.code in {'855288', '855290'}) // RxNorm

define "Is On NSAID":
  exists([MedicationRequest] M
    where M.status = 'active'
    and M.medication.coding.code in {'5640', '197805'}) // RxNorm

define "Has GI Bleed History":
  exists([Condition] C
    where C.code.coding.code in {'74474003'}) // SNOMED: GI hemorrhage

define "Risk Level":
  if "Has GI Bleed History" then 'critical'
  else if AgeInYears() > 65 then 'warning'
  else 'info'

// ThTxGNN 整合：替代建議
define "Alternative Analgesic Candidates":
  // 查詢 ThTxGNN 預測：哪些藥物可替代 NSAID 用於疼痛
  // 且不會與 Warfarin 交互
  null // 實際實作時連接 ThTxGNN API

待辦事項

  • 設計 ThTxGNN CDS Hooks 服務架構
  • 建立 Warfarin + NSAID 範例實作
  • 整合現有 DDI 資料到 CQL 值集
  • 設計 Card UI 元件
  • 實作 DetectedIssue 儲存（可選）

參考資源

建立日期：2026-03-01