Background Antibiotics are a strong risk factor for Clostridioides difficile infection (CDI), and CDI incidence is often measured as an important outcome metric for antimicrobial stewardship interventions aiming to reduce antibiotic use. However, risk of CDI from antibiotics varies by agent and dependent on the intensity (i.e., spectrum and duration) of antibiotic therapy. Thus, the impact of stewardship interventions on CDI incidence is variable, and understanding this risk requires a more granular measure of intensity of therapy than traditionally used measures like days of therapy (DOT). Methods We performed a retrospective cohort study to measure the independent association between intensity of antibiotic therapy, as measured by the antibiotic spectrum index (ASI), and hospital-associated CDI (HA-CDI) at a large academic medical center between January 2018 and March 2020. We constructed a marginal Poisson regression model to generate adjusted relative risks for a unit increase in ASI per antibiotic day. Results We included 35,457 inpatient encounters in our cohort. Sixty-eight percent of patients received at least one antibiotic. We identified 128 HA-CDI cases, which corresponds to an incidence rate of 4.1 cases per 10,000 patient-days. After adjusting for known confounders, each additional unit increase in ASI per antibiotic day is associated with 1.09 times the risk of HA-CDI (Relative Risk = 1.09, 95% Confidence Interval: 1.06 to 1.13). Conclusions ASI was strongly associated with HA-CDI and could be a useful tool in evaluating the impact of antibiotic stewardship on HA-CDI rates, providing more granular information than the more commonly used days of therapy.

中文翻译：

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抗生素暴露强度对艰难梭菌感染风险的影响

背景抗生素是艰难梭菌感染 (CDI) 的一个重要危险因素，CDI 发病率通常被作为旨在减少抗生素使用的抗菌管理干预措施的重要结果指标来衡量。然而，抗生素引起的 CDI 风险因药物而异，并取决于抗生素治疗的强度（即谱和持续时间）。因此，管理干预对 CDI 发生率的影响是可变的，要了解这种风险，需要比传统使用的治疗天数 (DOT) 等措施更精细地衡量治疗强度。方法 我们进行了一项回顾性队列研究，以测量 2018 年 1 月至 3 月期间在一家大型学术医疗中心通过抗生素谱指数 (ASI) 测量的抗生素治疗强度与医院相关 CDI (HA-CDI) 之间的独立关联2020。我们构建了边际泊松回归模型，以生成每抗生素日 ASI 单位增加的调整后相对风险。结果 我们的队列中纳入了 35,457 例住院患者。百分之六十八的患者至少接受了一种抗生素治疗。我们确定了 128 例 HA-CDI 病例，相当于每 10,000 患者日 4.1 例的发病率。调整已知的混杂因素后，每个抗生素日 ASI 每增加一个单位，HA-CDI 风险就会增加 1.09 倍（相对风险 = 1.09，95% 置信区间：1.06 至 1.13）。结论 ASI 与 HA-CDI 密切相关，并且可以成为评估抗生素管理对 HA-CDI 率影响的有用工具，提供比更常用的治疗天数更详细的信息。