1. What is Proportion of Days Covered (PDC)?

Definition: PDC is a medication adherence metric that measures the percentage of days a patient has medication available over a specified period.

Purpose: It helps healthcare providers assess medication adherence, particularly for chronic conditions where consistent medication use is crucial.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PDC \) — Proportion of Days Covered (percentage)
• \( DC \) — Days Covered (days medication was available)
• \( T \) — Total days in measurement period

Explanation: The days covered is divided by total days and multiplied by 100 to get a percentage adherence rate.

3. Importance of PDC Calculation

Details: PDC is widely used in healthcare quality measurement, with 80% typically considered the threshold for good adherence. Higher PDC correlates with better health outcomes.

4. Using the Calculator

Tips: Enter the days covered (DC) and total days in measurement period (T, default 30 days). DC must be ≤ T and both must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's considered a good PDC score?
A: Generally, PDC ≥ 80% indicates good adherence, though targets may vary by medication and condition.

Q2: How is DC (days covered) determined?
A: DC is calculated from prescription fill dates and days supply, accounting for early refills and overlapping coverage.

Q3: What's the typical measurement period (T)?
A: Common periods are 30, 90, or 365 days depending on the purpose of measurement.

Q4: How does PDC differ from MPR?
A: PDC accounts for overlapping coverage from multiple medications, while MPR (Medication Possession Ratio) does not.

Q5: Why multiply by 100 in the formula?
A: This converts the decimal result to a percentage for easier interpretation (e.g., 0.8 becomes 80%).