Centre for Biostatistics, The University of Manchester, Manchester, UK.
Manchester Centre for Clinical Neurosciences, Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Trust, Salford, UK.
Int J Stroke. 2023 Oct;18(9):1092-1101. doi: 10.1177/17474930231177881. Epub 2023 Jun 6.
Severe strokes and stroke-associated pneumonia (SAP) have long been associated with poorer patient health outcomes, for example, in-hospital mortality. However, it is unclear what role SAP plays in the risk of in-hospital mortality associated with a severe stroke at admission.
Using the Sentinel Stroke National Audit Program data on stroke admissions (2013-2018) in England and Wales, we modeled the "total" effect for severe stroke on risk of in-hospital mortality. Through four-way decomposition methodology, we broke down the "total" observed risk into four components. The direct "severity on outcome only" effect, the pure indirect effect of severity mediated via SAP only, the interaction between severity and SAP when mediation is not present, and when mediation via SAP is present.
Of 339,139 stroke patients included, 9.4% had SAP and 15.6% died in hospital. Of SAP patients, 45% died versus 12% of non-SAP patients. The risk ratio for in-hospital mortality associated with severe versus mild/moderate stroke (i.e. total effect) was 4.72 (95% confidence interval: 4.60-4.85). Of this, 43%-increased risk was due to additive SAP interaction, this increased to 50% for "very severe" stroke. The remaining excess relative risk was due to the direct severity on outcome effect only, that is, there was no evidence here for a mediation effect via SAP.
SAP was associated with a higher mortality in severe stroke patients. Prioritizing SAP prevention in severe stroke patients may improve in-hospital survival. Our results suggest that in severe stroke patients avoiding SAP might result in an up to 43% reduction in mortality.
严重中风和中风相关性肺炎（SAP）长期以来与患者健康状况恶化相关，例如住院死亡率。然而，SAP 在入院时严重中风相关住院死亡率风险中扮演什么角色尚不清楚。
我们使用英格兰和威尔士 Sentinel Stroke 国家审计计划中风入院数据（2013-2018 年），对严重中风对住院死亡率风险的“总”效应进行建模。通过四向分解方法，我们将观察到的“总”风险分解为四个组成部分。严重程度对结果的直接“仅严重程度”效应、仅通过 SAP 介导的严重程度的纯间接效应、严重程度和 SAP 之间不存在中介时的交互作用以及 SAP 存在中介时的交互作用。
在纳入的 339139 例中风患者中，9.4%患有 SAP，15.6%在医院死亡。在 SAP 患者中，45%死亡，而非 SAP 患者中为 12%。严重中风与轻度/中度中风相比的住院死亡率风险比（即总效应）为 4.72（95%置信区间：4.60-4.85）。其中，由于 SAP 附加交互作用，风险增加了 43%，对于“非常严重”的中风，这一比例增加到 50%。剩余的超额相对风险仅归因于直接严重程度对结果的影响，即 SAP 没有介导效应的证据。
SAP 与严重中风患者的死亡率升高相关。在严重中风患者中优先预防 SAP 可能会提高住院生存率。我们的结果表明，在严重中风患者中避免 SAP 可能导致死亡率降低 43%。
