Low Treatment Rates of Parasitic Diseases with Standard-of-Care Prescription Drugs in the United States, 2013-2019.

To assess appropriate drug treatment of parasitic diseases in the United States, we examined the treatment rates of 11 selected parasitic infections with standard-of-care prescription drugs and compared them to the treatment rates of two more common bacterial infections (Clostridioides difficile and streptococcal pharyngitis). We used the 2013 to 2019 IBM® MarketScan® Commercial Claims and Encounters and MarketScan® Multi-State Medicaid databases, which included up to 7 years of data for approximately 88 million and 17 million individuals, respectively, to estimate treatment rates of each infection. The number of patients diagnosed with each parasitic infection varied from 57 to 5,266, and from 12 to 2,018, respectively, across the two databases. Treatment rates of 10 of 11 selected parasitic infections (range, 0-56%) were significantly less than those for streptococcal pharyngitis and Clostridioides difficile (range, 65-85%); giardiasis treatment (64%) was comparable to Clostridioides difficile (65%) in patients using Medicaid. Treatment rates for patients with opisthorchiasis, clonorchiasis, and taeniasis were less than 10%. Although we could not verify that patients had active infections because of limitations inherent to claims data, including coding errors and the inability to review patients' charts, these data suggest a need for improved treatment of parasitic infections. Further research is needed to verify the results and identify potential clinical and public health consequences.