Establishing minimal clinically important differences and cut-off values for the lower limb motricity index and trunk control test in older patients with acute stroke: a prospective cohort study

Abstract

ABSTRACT Objective To establish the Minimal Clinically Important Differences (MCIDs) for lower limb strength measured by the Motricity Index (LLMI) and trunk function assessed by the Trunk Control Test (TCT) in the acute phase of stroke in older patients. Further, the study sought to determine the cutoff values predicting functional prognosis at discharge for both the LLMI and TCT. Methods This prospective cohort study was conducted for older patients (≥65 years) admitted for acute stroke, receiving guideline-based stroke care that includes early rehabilitation. The LLMI and TCT were measured within 7 days of admission and at discharge. The MCID was derived from receiving operating characteristic curves, based on a ≥ 1 point shift in the modified Rankin Scale (mRS) from admission to discharge. A good functional prognosis at discharge was defined as an mRS score of ≤ 3. Results A total of 201 older patients with acute stroke were included. The TCT achieved an MCID of 13 (area under the curve [AUC] = 0.704, 95% confidence interval [CI]: 0.633–0.775), whereas the LLMI lacked the precision to produce a significant MCID. The optimal cutoff points for predicting a good outcome were found to be an LLMI score of 65 (AUC = 0.770, 95% CI: 0.705–0.835) and a TCT score of 25 (AUC = 0.827, 95% CI: 0.768–0.887) upon admission. Conclusions This study identified a valid MCID for the TCT, failed to do so for the LLMI, and established cutoff values for both the LLMI and TCT that can predict good outcomes in older patients with acute stroke.