During a diabetes screening program in an urban slum in Delhi, 2,400 adults aged 30–60 years are screened using fasting blood glucose. The prevalence of diabetes is found to be 12%. The program coordinator wants to identify individuals at highest risk of progression to diabetes for targeted intervention. Which of the following is the most appropriate next step?

Explanation

## Risk Stratification in Community Diabetes Screening ### Epidemiological Principle: Targeted Screening **Key Point:** In resource-limited settings, universal OGTT is not cost-effective. Targeted screening using fasting glucose identifies those with **impaired fasting glucose (IFG: 100–125 mg/dL)** or **diabetes (≥126 mg/dL)**, and OGTT is then performed on IFG cases to detect **impaired glucose tolerance (IGT)** — the highest-risk group for progression [cite:Park 26e Ch 3]. ### Progression Risk Hierarchy | Category | Fasting Glucose | 2-hr Post-Load | Annual Progression to DM | Intervention | |---|---|---|---|---| | Normal | <100 | <140 | 1–2% | General health advice | | **IFG** | **100–125** | **<140** | **5–10%** | **OGTT + lifestyle** | | **IGT** | **<100 or 100–125** | **140–199** | **10–15%** | **Intensive lifestyle ± metformin** | | IFG + IGT | 100–125 | 140–199 | 15–20% | Intensive lifestyle + metformin | | Diabetes | ≥126 | ≥200 | — | Medical management | **High-Yield:** The **IFG + IGT overlap group** has the highest progression risk (15–20% annually). These individuals are identified by performing OGTT on IFG cases [cite:Park 26e Ch 3]. ### Screening Algorithm for Resource-Limited Settings ```mermaid flowchart TD A[Community screening: Fasting glucose]:::action --> B{Fasting glucose?}:::decision B -->|≥126 mg/dL| C[Diabetes]:::outcome B -->|100-125 mg/dL| D[IFG: Perform OGTT]:::action B -->|<100 mg/dL| E[Normal: Reassess in 3 years]:::action D --> F{2-hour post-load?}:::decision F -->|≥200| G[Diabetes]:::outcome F -->|140-199| H[IGT: Highest progression risk]:::outcome F -->|<140| I[Normal glucose tolerance]:::outcome H --> J[Intensive lifestyle intervention]:::action J --> K[Metformin if high-risk features]:::action ``` ### Why This Approach Is Cost-Effective 1. **Reduces unnecessary OGTT:** Only ~20–30% of screened population (those with IFG) undergo OGTT, not all 2,400. 2. **Identifies highest-risk group:** IGT cases (detected via OGTT on IFG) have 10–15% annual progression and are candidates for intensive intervention. 3. **Aligns with WHO guidelines:** Targeted OGTT in IFG cases is the recommended approach in low-resource settings [cite:Park 26e Ch 3]. ### Intervention Strategy for IGT Cases **Clinical Pearl:** The Diabetes Prevention Program (DPP) and Indian DPP equivalents show that intensive lifestyle modification in IGT reduces progression by 58%. Metformin reduces progression by 31% and is added if: - Age <60 years AND BMI >35 - Strong family history - Previous gestational diabetes ### Screening Yield in This Program - **Diabetic cases identified:** 12% × 2,400 = **288 cases** (fasting ≥126 mg/dL) - **IFG cases (estimated 15–20% of non-diabetic):** ~360–480 cases - **OGTT performed on:** ~360–480 cases (not all 2,400) - **IGT cases identified (estimated 30–40% of IFG):** ~108–192 cases → **targeted for intensive intervention**