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

The Proportion of Days Covered (PDC) is a medication adherence measure that calculates the percentage of days a patient has medication available over a specific period. It's commonly used to assess medication adherence for chronic conditions.

2. How Does the Calculator Work?

The calculator uses the PDC formula:

Where:

• \( \text{Days Covered} \) — Number of days the medication was available
• \( \text{Total Days} \) — Total days in the measurement period

Explanation: The equation calculates what percentage of days in the measurement period the patient had medication available.

3. Importance of PDC Calculation

Details: PDC is a key metric for assessing medication adherence, which is crucial for treatment effectiveness. Higher PDC values are associated with better health outcomes for chronic conditions.

4. Using the Calculator

Tips: Enter the number of days covered (when medication was available) and the total days in the measurement period. Both values must be positive integers, and days covered cannot exceed total days.

5. Frequently Asked Questions (FAQ)

Q1: What is considered good PDC?
A: Generally, PDC ≥80% is considered good adherence, though optimal thresholds may vary by medication and condition.

Q2: How is PDC different from MPR?
A: While similar, PDC accounts for overlapping medication fills and can't exceed 100%, making it a more conservative measure than Medication Possession Ratio (MPR).

Q3: What time period should be used for PDC?
A: Common measurement periods are 90 days, 180 days, or 365 days depending on the purpose of assessment.

Q4: How is days covered calculated for multiple medications?
A: For multiple medications in a therapy class, a day is counted as covered if at least one medication in the class is available.

Q5: What are limitations of PDC?
A: PDC doesn't confirm actual medication consumption and may be affected by early refills or stockpiling.