Methodologies for Observational Studies Comparing Inpatient COVID-19 Treatments

To apply and compare two different methodological approaches (one applying diagnostics steps and contingencies and the other not) to the illustrative example described below:Illustrative Example - Objective I aims to characterize the risk of inpatient mortality [Primary Outcome] and progression to invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO) [Secondary Outcome] up to 28 days after interleukin-6 receptor inhibitors (IL6Ri) or janus kinase inhibitor (JAKi) initiation among patients hospitalized with COVID-19 who initiate a corticosteroid of interest and require supplemental oxygen / non-invasive ventilation / high flow oxygen (O2/NIV/HFO) (but not IMV/ECMO).Illustrative Example - Objective II aims to characterize the risk of inpatient mortality [Primary Outcome] up to 28 days after IL6Ri or JAKi initiation among patients admitted to the ICU at hospital admission with COVID-19 who initiate a CSI and require IMV/ECMO.Hazard ratios (HR) and corresponding 95% confidence intervals (CI) will be estimated and reported for all outcome risks in Illustrative Example objectives.

Inclusion Criteria:Hospitalized from June 16, 2020 to February 01, 2022 with an ICD-10 diagnosis code of U07.1 in an any admitting diagnosis position (Day 0)Initiate either IL6Ri or JAKi within 4 days after hospital admission (Days 0 to 4)Receiving systemic CSI on day of IL6Ri/JAKi initiation (Day T)Receipt of at least one respiratory support procedure (oxygen supplementation at a minimum) from admission to IL6Ri/JAKi initiation (Days 0 to T)For Illustrative Example - Objective I only:-maximum mWHO disease severity of O2/NIV/HFO from admission to IL6Ri/JAKi initiation (Days 0 to T)For Illustrative Example - Objective II only:Admission to ICU at hospital admission (Day 0) and mWHO disease severity of IMV/ECMO from hospital/ICU admission to IL6Ri/JAKi initiation (Days 0 to T)Continuous medical claims enrollment (60-day gaps permitted) during the 183 day baseline period prior to and including hospital or ICU admission (Days -183 to 0) to minimize the potential for misclassification of baseline covariatesExclusion Criteria:Exclude patients without continuous medical claims enrollment (60-day gaps permitted) during the 183-day baseline period prior to and including hospital/ICU admission (Days -183 to 0) to minimize the potential for misclassification of baseline covariates.Exclude patients if COVID-19 hospitalization (Day 0) begins >14 days after initial COVID-19 diagnosis. Patients will be excluded if any COVID-19 diagnosis is recorded from 90 days to 15 days before admission (Days -90 to -15) to exclude patients with possible long-term COVID or post-acute sequelae while still permitting prior infections recorded more than 90 days pre-admission.No age, sex, or geographic region recorded on hospital admission (Day 0)Age less than 18 years at hospital admission (Day 0)Evidence of a prior COVID-related inpatient hospitalization in the previous 14 days (Days -14 to -3), with a two-day buffer to permit brief inpatient utilization directly proceeding transfer to a chargemaster hospital (i.e., inpatient utilization permitted on Days -2 to -1)Systemic CSI use (dispensing or remaining supply) in the previous 14 days (Days -14 to -3), with a two-day buffer to permit CSI use beginning in the emergency department or other healthcare setting immediately prior to chargemaster hospital admission (CSI use permitted Days -2 to -1)Any recorded use of IL6Ri or JAKi (dispensing or remaining supply) in the 90-day washout period before IL6Ri or JAKi initiation (Days -90 to T-1), to satisfy new use definitionBaseline receipt of oxygen or ventilation support for non-COVID conditions (e.g., supplemental oxygen for COPD), defined as two or more respiratory support procedures recorded on different days from Days -90 to -15 via procedure codes from medical claims, chargemaster, and where available, oxygen supplies recorded in pharmacy settings.Death or discharge occurs before or on the day of treatment initiation (Days 0 to T)Recorded use of both IL6Ri and JAKi on Day T