To explore the predictive efficacy of serum vitamin D level on lower limb strength loss in patients undergoing maintenance hemodialysis (MHD).

This is a cross-sectional study with convenient sampling. In 95 MHD patients who were selected from Blood Purification Center, Strategic Support Force Medicial Center from September 2018 to October 2018, serum 25(OH)D₃ level and a 5-repetition sit-to-stand test (5-STS) were used to represent serum vitamin D level and lower limb strength. MHD patients were divided into two groups based on the completion time of the 5-STS: normal muscle strength (n=85) and decreased muscle strength (n=10), and the demographic characteristics and laboratory indicators of the two groups were compared. The influencing factors of lower extremity muscle weakness were studied using multivariate logistic regression, and a receiver operating characteristic (ROC) curve was drawn to assess the specificity and sensitivity of the above factors in predicting lower extremity muscle weakness in MHD patients.

Serum 25(OH)D₃ levels ranged from 11.00 nmol/L to 99.50 nmol/L, with 31.23(19.90-43.30)nmol/L as the median, and the time to complete 5-STS ranged from 3.55 sec to 18.71 sec, with 9.81(7.12, 12.43) sec as the median. Lower limb strength decreased in 10 cases (10.53%). Multivariate logistic regression revealed that serum 25(OH)D₃ was a protective factor for lower limb weakness in MHD patients[OR=0.761, 95%CI(0.592-0.978), P=0.033]. ROC analysis revealed that the AUC of 25(OH)D₃ was 0.815, with sensitivity and specificity of 80.00% and 80.00%, respectively.

The level of serum 25(OH)D₃ is low in MHD patients especially in those with reduction of strength in lower limbs. The 25(OH)D₃ can predict the reduction of strength in lower limb of MHD patients with a satisfying sensitivity and specificity.