Development of a refill pattern method to measure polypharmacy in administrative claims databases

Area of Science:

• Health Services Research
• Pharmacoepidemiology
• Data Analytics

Background:

• Polypharmacy, the concurrent use of multiple medications, is a growing concern in healthcare, particularly in managing chronic conditions like attention deficit/hyperactivity disorder (ADHD).
• Accurately identifying polypharmacy in large administrative claims databases is crucial for patient safety and effective treatment strategies.
• Traditional methods using days' supply overlap may not fully capture complex medication-taking behaviors.

Purpose of the Study:

• To develop and validate a novel refill pattern method for identifying polypharmacy within pharmacy billing records.
• To compare the efficacy of this new method against established days' supply overlap algorithms.

Main Methods:

• The study assessed prescription refill patterns, defining concomitant therapy as repeated dispensing of two drugs within each other's active supply period.
• A simplified scenario focused on two ADHD medications: methylphenidate/dexmethylphenidate and atomoxetine.
• Prevalence of ADHD treatment polypharmacy was calculated over two years using the refill pattern method and compared with traditional 30-, 60-, and 90-day overlap algorithms.

Main Results:

• The refill pattern method identified polypharmacy in 3.1% of 131,385 children treated for ADHD.
• The prevalence estimate using the refill pattern method fell between the 30- and 60-day overlap methods.
• High agreement was observed between the refill pattern method and traditional methods, with Cohen's kappa values ranging from 0.80 to 0.92.

Conclusions:

• The refill pattern method provides a viable alternative for measuring polypharmacy in administrative claims data.
• This method is adaptable for diverse research questions, diseases, and populations.
• It offers a robust tool for pharmacoepidemiological studies and healthcare data analysis.