Pre-stroke frailty and 30-day functional outcomes in Vietnamese adults with acute stroke: a prospective observational study

Background Pre-stroke frailty may influence recovery after acute stroke, but prospective evidence from low- and middle-income countries remains limited. We investigated the association between pre-stroke frailty and 30-day functional outcome among Vietnamese adults with acute stroke. Methods This prospective study enrolled 188 adults aged ≥ 50 years with acute stroke at the National Geriatric Hospital, Vietnam. Pre-stroke frailty was assessed using the Clinical Frailty Scale (CFS 1–4 non-frail; 5–9 frail). The primary outcome, 30-day functional status (modified Rankin Scale, mRS 0–6), was analysed using a Bayesian partial proportional-odds cumulative-logit model, with frailty’s effect allowed to vary across mRS cut-points and other covariates constrained to proportional effects. Sensitivity analyses included a bias-reduced generalized ordinal model and binary logistic regression. Results Of 188 participants, 163 (86.7%) were frail and 107 (56.9%) had poor 30-day outcomes (mRS 3–6). In the primary Bayesian model, frailty estimates were above 1 across all six cumulative mRS cut-points (ORs 2.50–15.96). The 95% credible intervals excluded 1 at the mRS ≥ 1 through ≥ 4 cut-points but were wide and included 1 at mRS ≥ 5 and ≥ 6, where no non-frail participant was observed. Binary logistic regression for poor versus good functional outcome (mRS 3–6 vs. 0–2) yielded an adjusted OR of 8.49 (95% CI 2.40–30.0). Conclusions Pre-stroke frailty was associated with worse 30-day functional outcome in this single-center Vietnamese stroke cohort. External validation and formal assessment of incremental prognostic performance are required before clinical implementation.