A University of Chicago Medicine study published in Nature Communications last month revealed that certain regions of the United States preferred more expensive drugs while others favored cheaper, equally effective alternatives.  

The study was conducted by Andrey Rzhetsky, the Edna K. Papazian Professor of Medicine and Human Genetics, and postdoctoral scholar Rachel Melamed, who both concluded that state health care regulations, racial diversity, and wealth influenced prescription choices. Their study looked at the prescription rates of 600 popular drugs in over 2,000 counties across the U.S. 

Rzhetsky and Melamed obtained analyzed datasets from IBM Watson Health’s MarketScan, which included de-identified insurance claims for over 150 million Americans.  

They then analyzed demographic and geographic patterns, concluding that drug preference differed most between northern and southern states and between urban and rural states. New England states were most similar to some Midwestern states such as Minnesota and Wisconsin.  

By dividing available data into geographic regions and incorporating demographic and state health care spending data, Rzhetsky and Melamed found that wealthier, urban, and southeastern areas preferred more expensive drugs.  

However, the researchers said an exact reason for this discrepancy remains unclear. “The guess is ‘more expensive equals better’ in consumers’ minds,” Rzhetsky said. 

Though the researchers suggested that these patterns could be due to social or commercial factors such as pharmaceutical advertising, Rzhetsky added that “this probably cannot be answered without accessing additional advertisement data.” 

Additionally, the researchers indicated that holistic socioeconomic factors influenced drug prescriptions, especially for mental health treatment. Referring to higher levels of antipsychotic prescriptions in northern and western regions of the U.S. compared to the southern and eastern U.S., Melamed said, “I believe that the variation captured there is related to overall wellness and quality of medical care, so people who need antipsychotics are less likely to receive these drugs in the southeast of the country.” 

In future studies, Rzhetsky and Melamed hope to examine how patterns in drug usage change over time and how drug usage spreads across the country.