Objectives Patients undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT) have a higher risk of falls than those receiving other therapies for haematological disorders. This study aimed to investigate the impact of pretransplant lower extremity muscle strength (LEMS) on post-transplant falls.

Methods In this retrospective cohort study, patients aged ≥18 years who underwent allo-HSCT were included. All data were extracted from medical records. LEMS was defined as the knee extension force measured by a handheld dynamometer divided by the patient’s weight. The receiver operating characteristic (ROC) curve was used to calculate the optimal LEMS cut-off value for prediction of falls. Patients were categorised into low and normal LEMS groups based on the cut-off value. The impact of pretransplant LEMS on post-transplant falls was analysed using a Cox proportional hazards model.

Results In total, 101 patients were analysed. During the observation period, falls occurred in 32 patients (31.7%). The ROC curve analysis results showed that the optimal LEMS cut-off value for prediction of falls was 45.4% per body weight. In multivariate analysis, pretransplant low LEMS was a significant predictor of falls in model 1 with patient characteristics as a confounding factor and model 2 with medications-inducing falls as a confounding factor, respectively (model 1: HR 3.23, 95% CI 1.37 to 7.64; model 2: HR 2.82, 95% CI 1.20 to 6.59).

Conclusions Pretransplant LEMS was a significant predictor of post-transplant falls. The results of this study may help to prevent falls in patients undergoing allo-HSCT.