时间标签：数据日期 2026-10-31 · 生成时间 2026-11-01 05:30（Asia/Shanghai）｜ 检索窗口 PubMed edat 2026/10/28–2026/10/31 ｜ 情报发生日期 2026-10-31
研究问题
The potential for LC to increase economic disparities highlights the urgent need to understand whether medications at the time of SARS‐CoV‐2 infection affect the risk of developing LC.；However, only 22% of the trial participants were enrolled during the Omicron era, enrollment was restricted by age (30–85 years) and body mass index (BMI) ≥ 25 kg/m2, and the LC outcome was diagnosis by a clinician.；When using EHR data, it may not be possible to determine the exact reason a medication was prescribed, and thus whether the medication was taken during the timeframe of interest (i.e., during acute infection).
方法
Target trial emulation (TTE) in adults with documented SARS‐CoV‐2 infection in the National COVID Cohort Collaborative (N3C) database.；The target trials emulated are the COVID‐OUT and ACTIV‐6 trials, both randomized, blinded, decentralized trials of metformin versus exact‐matching placebo to assess whether metformin during acute infection prevents LC [, ].；By explicitly specifying eligibility criteria, treatment initiation, follow‐up, outcome assessment, and target estimand as an RCT would, TTE can reduce common biases and pitfalls in observational studies such as immortal time bias and confounding [].；The follow‐up in this TTE closely emulates the target trials, in which participants did not receive therapy at the outset of symptoms or immediately upon a positive test.
核心结论
Before weighting, the metformin group was older, had a higher mean BMI and mean HbA1c; and a larger portion was male (Table ).；A minority of the metformin (10%) and control (5%) prescriptions were on Day 5 or later (Table ).；The primary analytic sample was those receiving a metformin or comparator prescription within Days 0–6 relative to infection. ‖ 结论：These results are also consistent with a recent sequential target trial analysis in the United Kingdom that assessed metformin started within 90 days of infection, HR 0.36 (95% CI 0.32–0.41) [].
局限
However, in both an RCT and this TTE, subgroups lack precision and should be interpreted with caution.；Observational analyses may be limited by missing data and misclassification of exposures, outcomes, and confounders.；For example, the use of nirmatrelvir–ritonavir may not be captured in the EHR because individuals were able to obtain nirmatrelvir–ritonavir directly from pharmacies without seeing their physician.
对本项目的价值
★☆☆☆☆ 干预证据决定参照标准效应量——任何抗衰干预的收益至少应对标该基线。
全文来源
PMC JATS 全文（正文 24,627 字符，已过标题/DOI 逐字归属校验）
原文题录
- 英文标题：Metformin at the Time of COVID-19 Infection and Risk of Long COVID: A Target Trial Emulation Study.
- 期刊与标识：J Med Virol · PMID 42954425 · DOI 10.1002/jmv.71190
A 级证据分级：A 级（同行评议人体研究）
本文属人体研究证据，但需注意：观察性或小样本干预的结论不等于已证实临床获益；效应量与长期安全性仍需更大规模、更长随访的试验验证。
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