A public health epidemiologist is conducting a cross-sectional survey in a rural district of Maharashtra to estimate the burden of type 2 diabetes mellitus. The survey identifies 450 cases of diabetes among 5,000 randomly selected adults aged ≥30 years. The district has a total adult population of 200,000. What is the most appropriate next step to establish the disease burden and guide resource allocation for diabetes management programs?

Explanation

## Understanding the Epidemiological Question The stem describes a **cross-sectional survey** — a snapshot survey at a single point in time. The key data provided are: - 450 cases identified - 5,000 individuals surveyed - Total district population: 200,000 ## Why Point Prevalence is the Correct Next Step **Key Point:** In a cross-sectional survey, the appropriate measure of disease frequency is **point prevalence**, not incidence. Point prevalence answers: "How many people have the disease at this moment?" ### Calculation $$\text{Point Prevalence} = \frac{450}{5,000} = 0.09 = 9\%$$ ### Application to Resource Planning **High-Yield:** Once prevalence is calculated, it can be **extrapolated to the total population** to estimate the absolute disease burden: $$\text{Estimated cases in district} = 0.09 \times 200,000 = 18,000 \text{ cases}$$ This estimate directly informs: - Number of clinics and healthcare workers needed - Drug procurement and supply chain planning - Budget allocation for diabetes management programs - Screening and awareness campaign targets ## Distinction: Prevalence vs. Incidence | Measure | Definition | When Used | Study Design | |---------|-----------|-----------|---------------| | **Point Prevalence** | Proportion with disease at a specific time | Disease burden, resource planning | Cross-sectional | | **Period Prevalence** | Proportion with disease during a time period | Chronic disease tracking | Cross-sectional | | **Incidence** | New cases occurring in disease-free population | Disease risk, etiology | Cohort, prospective | **Clinical Pearl:** Prevalence = Incidence × Duration of disease. For chronic diseases like diabetes, prevalence is much higher than incidence because patients live with the condition for years. ## Why This Approach Answers the Public Health Question The epidemiologist's goal is to **establish disease burden** — i.e., how many people in the district are affected **right now**. This is a prevalence question, not an incidence question. The cross-sectional survey is the appropriate design and point prevalence is the appropriate metric. [cite:Park 26e Ch 5]