Objective To explore the current status of serum phosphorus level in patients on maintenance hemodialysis (MHD), examine its relationship with clinical parameters and determine the influencing factors of serum phosphorus level.
Methods For this multicenter cross-sectional study, 2667 patients on MHD at 27 domestic dialysis centers were recruited from 2019 to 2020. Demographic profiles, primary diseases and laboratory tests were recorded. According to serum phosphorus (P) level, they were assigned into three groups of low blood phosphorus (P<1.13 mmol/L), normal blood phosphorus (1.13≤P≤1.78 mmol/L) and high blood phosphorus (P<1.78 mmol/L). One-way analysis of variance (ANOVA) was performed for examining the differences in clinical parameters among three groups. Multiple linear regression was performed for examining the influencing factors associated with serum phosphorus level.
Results Low/normal/high blood phosphorus groups accounted for 7.6%, 35.3% and 57.1% respectively. Spearman's correlation analysis revealed that age (r = −0.167, P<0.001) was correlated negatively with blood phosphorus level. Body weight (r = 0.09, P<0.001), body mass index (BMI)(r = 0.088, P<0.001), hemoglobin (r = 0.099, P<0.001), blood urea nitrogen (BUN) (r = 0.4, P<0.001), creatinine (r = 0.357, P<0.001), blood magnesium (r = 0.253, P<0.001), serum albumin (r = 0.117, P<0.001), uric acid (r = 0.253, P<0.001), parathyroid hormone (r = 0.299, P<0.001), total cholesterol (r = 0.1, P<0.001), triglyceride (r = 0.09, P<0.001), low-density lipoprotein cholesterol (r = 0.043, P = 0.027) and elderly nutritional risk index (r = 0.162, P<0.001) were positively correlated. Multiple linear regression revealed that blood phosphorus level was correlated independently with BMI (β = 0.163, P<0.001), hemoglobin (β = 0.06, P = 0.001), BUN (β = 0.238, P<0.001), creatinine (β = 0.152, P<0.001), blood magnesium (β = 0.117, P<0.001) and parathyroid hormone (β = 0.196, P<0.001).
Conclusion High phosphorus level appears a high proportion of MHD patients. Hemoglobin, BUN, creatinine, blood calcium, blood magnesium and parathyroid hormone are independent influencing factors for lower level of blood phosphorus in MHD patients.