OBJECTIVES: Early in a COVID-19 pandemic, antiviral drugs were not available, but guidelines for COVID-19 treatment have been published since early and have changed frequently. Therefore, treatment for COVID-19 may have changed with the recommendation in the guidelines. We examined whether prescriptions changed in response to changes in the guidelines using a comprehensive Japanese health claims database.

METHODS: We analyzed the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) that included all health insurance claims data issued in Japan (January 2020–June 2022). Prescriptions for COVID-19 were identified as drugs prescribed in the same month as the COVID-19 diagnosis and with a code indicating payment support from the government, as all healthcare expenses for COVID-19 were supported by the government. Prescription patterns were analyzed for drugs approved or listed as candidates for COVID-19 treatment in the guidelines.

RESULTS: The dataset included 6,612,147 patients diagnosed with COVID-19. Ciclesonide and lopinavir/ritonavir were included in the guidelines as candidates in the first quarter (Q1) 2020 and were the first and third most prescribed drugs. Azithromycin was the second most prescribed drug in Q1 2020 and became the top when it was added to the guidelines as a candidate in Q2 2020. Prednisolone was the second most frequently prescribed drug in Q2 2020 when the steroid was suggested as a candidate. Dexamethasone was the top from Q3 2020, when the recommendation of steroid changed to specify dexamethasone, to Q1 2022 (prescribed to 2,887–66,491 patients/Q). Remdesivir was approved for severe COVID-19 patients in May 2020; its prescription appeared in the database after NHI price listing in August 2021, and became the second highest in Q1 2022 (to 39,603 patients) and later.

CONCLUSIONS: We observed changes in prescription patterns in real-word situations corresponding to changes in recommendations in the guidelines.