OBJECTIVES: To assess newly diagnosed long COVID in a large US claims database.

METHODS: New diagnoses of long COVID from 01Apr2020 to 30Sep2022 were identified in a large US claims database. Long COVID was defined as having either (1) ICD-10 code U07.1 or U07.2 (COVID-19 with and without laboratory test, respectively) followed by ICD-10 code B94.8 (sequelae of other specified infectious and parasitic diseases), or (2) ICD-10 code U09.9 (post COVID-19 condition, effective since 01Oct2021).

RESULTS: During the study period, 998,532 patients were diagnosed with long COVID. The majority (818,898 patients, 82%) were diagnosed from 01Oct2021 onwards, of whom 796,269 (97%) with the U09.9 ICD-10 code. The number of new U09.09 diagnoses peaked between January and March 2022, with 7,988 new diagnoses on 31Jan2022 alone, the highest on any single day. Still 196,602 patients received a new U09.09 diagnosis in the three months preceding data cutoff (July through September 2022), representing a quarter of all patients receiving this diagnosis code. The overwhelming majority of patients (94%) were diagnosed on weekdays. Patients with a U09.09 diagnosis had a mean age of 51.9 years (SD 19.3), 63% were aged <60 years, 4% were aged <15 years, and 62% were women.

CONCLUSIONS: These results reflect long COVID diagnoses in the normal care setting in a population of individuals with health insurance coverage in the US. More women than men received a long COVID diagnosis, which confirms previous research. More than half of diagnosed patients belong to the working-age population. The wave of new long COVID diagnoses seen in this analysis between January and March 2022 directly followed a wave of new COVID-19 cases in the United States (CDC data). That most patients were diagnosed on weekdays may be explained that these diagnoses are made mostly in the non-acute care setting.