Association between upper limb motor function and balance in patients after stroke: a multicenter cross-sectional study

Using cross-sectional data from 26 general hospitals in China that treated stroke patients in the Department of Rehabilitation Medicine, the aim of this research is to explore the potential association between upper limb motor function and balance function after stroke. We conducted a prospective cross-sectional study involving 1573 stroke patients hospitalized in the rehabilitation medicine departments of 26 hospitals across China. Upper limb motor function and balance were evaluated using the Fugl-Meyer Assessment-Upper Extremity (FMA-UE) and the Berg Balance Scale (BBS), respectively. Linear regression analysis and smoothing curve fitting were performed to examine the relationship between upper limb motor and balance functions. This study included 1573 non-pregnant adults aged 18 years or older, with a mean age of 61.2 ± 12.5 years, of whom 69.0% were male. After adjusting for potential confounders, a significant positive association was observed between upper limb motor function and balance function after stroke (β = 0.48, 95% CI: 0.44-0.51, p < 0.001). Subgroup analyses indicated that this association was more pronounced in the acute phase (≤ 7 days) compared with the subacute and recovery phases. No significant interactions were detected across other subgroups (p > 0.05 for all interactions). Smooth curve fitting revealed distinct saturation effects for FMA-UE and BBS, with inflection points at 25 and 45, respectively. Sensitivity analyses further confirmed these results, supporting the robustness of the findings. This study identified a significant positive association between upper limb motor function and balance function following stroke, highlighting the potential role of upper limb motor recovery in predicting balance outcomes. Further large-scale and multidimensional studies are needed to clarify the underlying mechanisms linking upper limb motor control and post-stroke balance function.