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Adherence Calculator

Calculate Percent Days Covered (PDC) from Kroll RxSummary CSV exports.

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Adherence calculations are based on fill dates and inferred day supply from prescription directions. They may not reflect actual medication use. Review results and confirm against the patient chart.

Step 1 — Load CSV

Export RxSummary report from Kroll as CSV, then select it below.

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Step 2 — Calculate

Click Calculate to run the PDC analysis. Results appear in the tabs below.

Edit Day Supply

User Guide — Generating CSV from Kroll

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About This Tool

MEDICATION ADHERENCE CALCULATOR This tool analyzes prescription fill data to calculate medication adherence rates. It is designed to work with CSV exports from Kroll pharmacy software (RxSummary report). KEY FEATURES: • Automated PDC calculations based on fill dates and inferred day supply • Summary view showing average adherence by medication • Detailed view showing individual prescription fills • Editable day supply values for manual corrections • PDF and CSV export WHAT YOU NEED: • CSV file from Kroll (RxSummary report) • Basic understanding of adherence metrics This tool provides a structured, reproducible way to estimate adherence, supporting pharmacist-led interventions and documentation.
HOW ADHERENCE IS CALCULATED 1. DATA PROCESSING: • Loads prescription fill data from CSV • Groups prescriptions by medication and strength • Sorts fills by date to establish chronological order 2. DAY SUPPLY CALCULATION: • Extracts day supply from prescription directions using Sig pattern matching • Example: "Take 1 tablet daily" + quantity 30 → 30-day supply • Allows manual editing of day supply values 3. ADHERENCE CALCULATION: • Adherence % = (Day Supply ÷ Actual Days Between Fills) × 100 4. SUMMARY STATISTICS: • Averages adherence across all fills for each medication EXAMPLE: • Fill 1: January 1st, 30-day supply • Fill 2: February 5th (35 days later) • Adherence = (30 ÷ 35) × 100 = 85.7%
INTERPRETING RESULTS ADHERENCE THRESHOLDS: • Above 90% — Good (green) • 80–90% — At Risk (amber) • Below 80% — Poor (red) These thresholds are based on research linking adherence below 80% to adverse clinical outcomes. SUMMARY VIEW: • Shows average adherence per medication • More fills = more reliable average • Medications with few fills may show skewed results DETAILED VIEW: • Individual fills and their adherence rates • Actual days between fills vs. expected day supply RED FLAGS: • Consistently low adherence across multiple medications • Large gaps between expected and actual refill dates • Adherence >100% may indicate early fills or inaccurate day supply
WHY ADHERENCE MATTERS Adherence below 80% is linked to increased hospitalizations, disease progression, and mortality in chronic conditions including hypertension, diabetes, heart failure, and mental illness. EFFECTIVE INTERVENTIONS: • Compliance Packaging: 5–15% improvement over usual care • SMS Reminders: 10–20% improvement, better disease control • Automatic Refills: Modest but reliable gains • Pharmacist-led MTM: 15–25% improvement, reduced hospital admissions Monitoring adherence allows pharmacists to identify at-risk patients, implement targeted interventions, and document outcomes-based care.
LIMITATIONS • Results depend on accurate prescription data in source system • Day supply calculations may not reflect actual patient usage • Does not account for medication sharing, splitting, or disposal • Assumes patients take medication consistently during each fill period • PRN medications are not suitable for adherence calculations • Missing or incomplete data affects calculation accuracy PRIVACY: • Users are responsible for PHIPA/PIPEDA compliance • No patient data is stored or transmitted by this tool • Secure handling and timely disposal of CSV files is essential Always verify results against patient charts. Use as a screening tool, not a definitive assessment.

Help & FAQ

Q: What file format does the tool accept? A: CSV files exported from Kroll pharmacy software using the RxSummary report. Q: Why are some adherence percentages over 100%? A: Percentages over 100% indicate early refills — possible stockpiling or inaccurate day supply. These are capped at 100% in exported reports. Q: How accurate are the day supply calculations? A: Day supply is extracted from prescription Sig codes using pattern matching. Use the "Edit Day Supply" button in the Detailed tab to correct any inaccuracies. Q: Can I exclude certain medications from analysis? A: Yes — use the checkboxes in the Summary tab to select only the medications you want to export. Q: What should I do if calculations seem wrong? A: Verify day supply values in the Detailed tab, edit if necessary, then click "Recalculate." Q: How do I handle PRN medications? A: PRN medications are not suitable for adherence calculations. Deselect them in the Summary tab before exporting. Q: Can I save my work? A: Use the Export functions to save results as CSV or PDF. Data is not saved automatically and is cleared when you leave the page. Q: What if I get an error loading my CSV? A: Ensure the file is an RxSummary export from Kroll, is not open in another program, and has not been modified. Check the User Guide for required column names. Q: How do I generate the PDF report? A: Select the medications you want included using the checkboxes in the Summary tab, then click "Export PDF."