Abstract
BACKGROUND: Pneumonia is a frequent complication post-stroke and stress hyperglycemia (SH) is a physiological response to stroke. Although some studies have provided data on the impact of stress hyperglycemia on pneumonia incidence, no study to date has exclusively focused on investigating the direct relationship between stress hyperglycemia and pneumonia. METHODS: A comprehensive literature search was conducted across PubMed, EBSCOhost, Web of Science, Embase, CNKI, and Wanfang databases from inception to July 10th, 2024, to identify observational studies comparing the incidence of pneumonia between stroke patients with and without stress hyperglycemia. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS), and pooled ORs for each comparison were estimated using a random-effects model proposed by DerSimonian and Kacker. This systematic review is presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. RESULTS: Twelve studies were included eventually and the pooled incidence rate of pneumonia was 14.4%. The overall incidence of pneumonia in patients with stress hyperglycemia was significantly higher than in those without stress hyperglycemia (OR: 2.01; 95% CI: 1.72 to 2.34, P < 0.01).Significant heterogeneity was observed in the meta-analysis (P = 0.01, I²=54%). Meta-regression revealed that the effect size differed significantly across subgroups defined by SH metrics (blood glucose versus stress hyperglycemia ratio and blood glucose to HbA1c ratio, p < 0.01). These findings underscore important limitations, including measurement variability, significant heterogeneity, and potential residual confounding due to factors such as dysphagia severity, comorbidity burden, and variations in clinical management. Importantly, the overall quality of evidence was rated as low based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework, primarily due to the observational design of the included studies and inconsistency across results. Therefore, the findings should be interpreted cautiously and regarded as hypothesis-generating. CONCLUSIONS: This systematic review and meta-analysis found that SH was significantly associated with post-stroke pneumonia, with patients exhibiting SH having twice the odds of pneumonia compared to those without. PROSPECTIVE REGISTRATION: The protocol for this review is registered with the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42024563263.