2023 FDA Science Forum
Estimating real-world treatment effects under a rapidly evolving treatment paradigm
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Contributing OfficeOffice of the Commissioner
Abstract
METHODS Following the RECOVERY trial report that dexamethasone reduced mortality by 36% in UK patients hospitalized with COVID-19 on invasive mechanical ventilation (IMV), our use case aimed to evaluate this effect in routine care in the US. From patients in HealthVerity data hospitalized with COVID-19 April 2020-March 2021, those with dexamethasone initiation within 21 days post-admission were matched on calendar date, age, sex, baseline comorbidity score, days since admission, and COVID-19 severity to those not treated with corticosteroid of interest (CSI) at index date. Patients were subsequently propensity score (PS) matched 1:1 and followed from the day after index until death, discharge, or 28 days for initial-treatment hazard ratios (IT-HRs). Post hoc analyses among the IMV subgroup also truncated follow-up at 7 and 14 days. RESULTS In the IMV subgroup, 48% of non-CSI patients initiated a CSI the day after index and 67% by day 7; the IT-HR for dexamethasone versus non-CSI was 1.02 [95% CI 0.89-1.18] at 28 days, 0.81 [0.63-1.05] at 7 days, and 0.95 [0.80-1.14] at 14 days. CONCLUSION While the IMV 28-day mortality results were inconsistent with the RECOVERY trial findings, the 7-day post hoc results were directionally consistent. Adding a second diagnostic step after evaluating baseline criteria to evaluate pre-specified follow-up criteria (i.e., treatment utilization and censoring) may increase interpretability of findings, especially under a rapidly evolving treatment paradigm.
