1. What is Prevalence Ratio?

The Prevalence Ratio (PR) compares the prevalence of a condition (like diabetes) between two groups - an exposed group and an unexposed group. It's a measure of association used in cross-sectional studies.

2. How Does the Calculator Work?

The calculator uses the Prevalence Ratio formula:

Where:

• \( Prevalence\ exposed \) — Proportion with the condition in exposed group (0-1)
• \( Prevalence\ unexposed \) — Proportion with the condition in unexposed group (0-1)

Interpretation:

• PR = 1: No association between exposure and outcome
• PR > 1: Higher prevalence in exposed group
• PR < 1: Lower prevalence in exposed group

3. Importance of Prevalence Ratio

Details: Prevalence Ratio is important in public health for assessing disease burden, identifying risk factors, and planning interventions. For diabetes, it helps understand how different populations are affected.

4. Using the Calculator

Tips: Enter prevalence values as decimals between 0 and 1 (e.g., 0.15 for 15%). The unexposed prevalence must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: How is PR different from odds ratio?
A: PR uses prevalence (proportion with condition) while odds ratio uses odds. PR is more intuitive but can't be used in case-control studies.

Q2: What's a meaningful PR value for diabetes?
A: In diabetes research, PR > 1.2 often suggests meaningful association, but depends on context and confidence intervals.

Q3: When should I use PR vs risk ratio?
A: Use PR for cross-sectional studies (measuring prevalence), risk ratio for cohort studies (measuring incidence).

Q4: How do I convert percentages to decimals?
A: Divide percentage by 100 (e.g., 25% = 0.25).

Q5: Can PR be greater than 1?
A: Yes, PR > 1 means higher prevalence in exposed group. There's no upper limit to PR values.