ObjectiveTo explore the association between frailty and in-hospital mortality in older patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods Elderly patients who were hospitalized with AECOPD from June 2022 to December 2022 at a large tertiary hospital were selected. The independent prognostic factors including frailty status were determined by multivariate logistic regression analysis. Mediation effect analysis was used to evaluate the mediating relationships between C-reactive protein (CRP) and albumin and in-hospital death. ResultsThe training set included 1 356 patients (aged 86.7±6.6), 25.0% of whom were diagnosed with frailty. The multiple logistic regression analysis showed that frailty, mean arterial pressure, Charlson comorbidity index, neutrophil–lymphocyte ratio, interleukin-6, CRP, albumin, and troponin T were associated with in-hospital mortality. Furthermore, CRP and albumin mediated the associations between frailty and in-hospital mortality. ConclusionFrailty may be an adverse prognostic factor for older patients admitted with an AECOPD. CRP and albumin may be parts of mechanism between frailty and in-hospital death.