The FDA took vendor IQVIA to task for a discrepancy in data regarding sales of opioid drug products that the agency said could undermine forecasts used in the fight against addiction.

IQVIA collects data to measure the volume of drugs sold by manufacturers and wholesalers to pharmacies and hospitals. While conducting an analysis to estimate the amount of opioids sold in the U.S., the agency found a discrepancy in the IQVIA data that showed a more than 20 percent drop in the reported amount, expressed in kilograms, of fentanyl sold for a minimum of the past five years compared to what IQVIA’s database had previously reported.

Based on a subsequent investigation and discussions with IQVIA, the FDA determined that IQVIA overestimated past data because of an error in its methods, which the agency believes resulted from the vendor utilizing the wrong weight-based conversion factors to determine the amount of fentanyl in a given unit (such as a single fentanyl patch) for a subset of prescription fentanyl products.

“While data on sales volume expressed in kilograms are used only narrowly by the FDA… we are sharing this information publicly because these data have been used in forecasts that have the potential to impact ongoing work to fight the opioid epidemic,” the agency said.

The agency also looked at IQVIA’s data for similar mistakes related to other controlled substances and found more data quality issues related to controlled substances with similar weight-based conversion factors—including oxymorphone and hydrocodone—raising serious concerns about the data vendor’s data and quality control.

FDA Commissioner Scott Gottlieb requested that IQVIA hire a third party auditor to review its data quality and quality control procedures for the controlled substance data the agency used. He also requested that the third party conduct an independent audit of the data quality and quality control of all IQVIA products used by the agency.

The agency will be “working with federal partners on these issues and briefing members of Congress on IQVIA’s data quality issues and their potential public health implications,” the agency said. “We will provide updates to the public and our public health partners as appropriate.”

IQVIA said it has already addressed the data issues and informed clients about the error.

The company’s “internal processes had already identified the measurement conversion issue prior to the FDA’s notification,” IQVIA said. “We notified our clients about this measurement conversion issue in April of this year. Ongoing steps have been undertaken to correct this measurement conversion issue.”