Impact of pre-existing frailty on all-cause mortality in stroke survivors: a systematic review and dose–response meta-analysis

BACKGROUND: The association between pre-existing frailty and increased mortality in stroke survivors remains unclear, with prior studies reporting inconsistent findings. This meta-analysis aimed to evaluate the impact of pre-stroke frailty on all-cause mortality in this population. METHODS: We systematically searched PubMed, Embase, Web of Science, Cochrane Library, CINAHL, PsycINFO, CNKI, Wanfang, VIP, and SinoMed databases up to November 12, 2024. Study selection and data extraction were independently performed by two investigators. Studies using validated frailty assessment tools and reporting adjusted hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were included. RESULTS: Sixteen studies involving 55,897 patients met the inclusion criteria. The prevalence of frailty among stroke survivors ranged from 11.2% to 75.3%. Meta-analysis showed that pre-stroke frailty was significantly associated with increased all-cause mortality (pooled HR = 2.19, 95% CI: 1.44-3.34; pooled OR for continuous frailty scores = 1.26, 95% CI: 1.14-1.38). Dose-response analysis revealed a linear relationship, with each one-point increase in frailty score associated with a 6.4% higher risk of death (HR = 1.064, 95% CI: 1.031-1.098). Subgroup analyses indicated that the association was particularly strong in acute ischemic stroke populations (OR = 3.43, 95% CI: 1.81-6.51). The type of frailty assessment tool and study sample size were identified as potential sources of heterogeneity. CONCLUSION: Pre-stroke frailty independently predicts all-cause mortality in stroke survivors. Even mild increases in frailty burden are associated with worse outcomes, highlighting the clinical importance of incorporating frailty assessment into prognostic evaluation.