Patient and treatment pathways for toxoplasmosis in the United States: data analysis of the Vizient Health Systems Data from 2011 to 2017

Toxoplasmosis causes substantial morbidity and mortality in the United States (US). Clinical manifestations to toxoplasmosis vary and there is limited information on incidence or treatment patterns in the US. Treatment pathways for pyrimethamine-based regimens and trimethoprim-sulfamethoxazole (TMP-SMX) for toxoplasmosis hospitalizations were investigated using the Vizient Health Systems inpatient and outpatient data. Between January 1(st), 2011 and December 31(st), 2017, 10,273 hospital visits from 4,736 unique patients received a primary or secondary ICD-9/ICD-10 diagnosis for toxoplasmosis. The projected annual hospital visits with a diagnosis of toxoplasmosis was 68,821, corresponding to a total annual incidence of 9,832 comprising ocular toxoplasmosis of 2,169, toxoplasmic encephalitis of 1,399, unspecified toxoplasmosis of 4,368, congenital toxoplasmosis of 381, multisystemic toxoplasmosis of 69 and other toxoplasmosis of 1,446. Only 16.3% of the study population received treatment with pyrimethamine-based regimens or TMP-SMX. Pyrimethamine-based regimens were used significantly more often than TMP-SMX in toxoplasmic encephalitis (88.7% vs 79.6%, p = 0.01), other toxoplasmosis (85.0% vs 79.2%, p = 0.04), and unspecified toxoplasmosis (87.6% vs 77.9%, p = 0.03) in hospitals with 300 beds or more. A significantly higher percentage of visits with TMP-SMX as first-line treatment switched to pyrimethamine-based regimens compared to visits initiated on pyrimethamine-based treatments (26.7% vs 4.1%, p <.001). Ocular toxoplasmosis patients receiving pyrimethamine-based therapy were more likely to be discharged home compared to TMP-SMC at rates of 72.4% and 55.2%, respectively. Our analysis of commercial insurance records suggest toxoplasmosis is undertreated. Overall, pyrimethamine-based regimens are favored over TMP-SMX, have higher rates of discharge home, and have lower switch rates.