text: Late Conditions Diagnosed 1 4 Months Following an Initial Coronavirus Disease 2019 COVID 19 Encounter A Matched Cohort Study Using Inpatient and Outpatient Administrative Data United States 1 March 30 June 2020 Late sequelae of COVID 19 have been reported however few studies have investigated the time course or incidence of late new COVID 19 related health conditions post COVID conditions after COVID 19 diagnosis Studies distinguishing post COVID conditions from late conditions caused by other etiologies are lacking Using data from a large administrative all payer database we assessed type association and timing of post COVID conditions following COVID 19 diagnosis Using the Premier Healthcare Database Special COVID 19 Release release date 20 October 2020 data during March June 2020 27 589 inpatients and 46 857 outpatients diagnosed with COVID 19 case patients were 1 1 matched with patients without COVID 19 through the 4 month follow up period control patients by using propensity score matching In this matched cohort study adjusted ORs were calculated to assess for late conditions that were more common in case patients than control patients Incidence proportion was calculated for conditions that were more common in case patients than control patients during 31 120 days following a COVID 19 encounter During 31 120 days after an initial COVID 19 inpatient hospitalization 7 0 of adults experienced 1 of 5 post COVID conditions Among adult outpatients with COVID 19 7 7 experienced 1 of 10 post COVID conditions During 31 60 days after an initial outpatient encounter adults with COVID 19 were 2 8 times as likely to experience acute pulmonary embolism as outpatient control patients and also more likely to experience a range of conditions affecting multiple body systems eg nonspecific chest pain fatigue headache and respiratory nervous circulatory and gastrointestinal symptoms than outpatient control patients These findings add to the evidence of late health conditions possibly related to COVID 19 in adults following COVID 19 diagnosis and can inform healthcare practice and resource planning for follow up COVID 19 care 