Abstract: Objective  To investigate the association between hyperphosphatemia and cognitive impairment in patients on continuous ambulatory peritoneal dialysis (CAPD).  Methods  This is a single-centered study recruited a total of 312 CAPD patients from the Second Hospital of Hebei Medical University in the period of January 2021 to December 2022. Their general cognitive function was examined using the Montreal Cognitive Assessment (MoCA), and their executive function was assessed by Test A (Trail-Making Test forms A, TA).  Results were statistically processed by SPSS 26.0.  Results  ①Among the 312 CAPD patients, the prevalence of cognitive impairment was 36.9%. ②Univariate correlation analysis showed that hyperphosphatemia (OR=2.333, 95% CI：1.456～3.736, P＜0.001) and age (OR=0.830, 95% CI：1.076～1.135, P＜0.001) were correlated with general cognitive function, and serum albumin (OR=0.869, 95% CI：0.770～0.982,       P=0.024) and age (OR=1.073, 95% CI：1.024～1.124, P=0.003) were correlated with executive function. There were no significant correlation between serum levels of calcium (OR=0.218, 95% CI：0.048～0.999, P=0.050) and iPTH (OR=1.000, 95% CI：0.999～1.001, P=0.484) and general cognitive and executive functions. ③Multivariate regression analysis suggested that hyperphosphatemia was significantly associated with cognitive impairment (95% CI：3.272～17.741, P＜0.001) after adjustments for demographic, clinical and laboratory confounding factors. The incidence of cognitive impairment in CAPD patients with hyperphosphatemia was 7.62 times higher than that in the patients without hyperphosphatemia. ④ ROC curve indicated that when blood phosphorus was set at 1.66mmol/L, the maximum value of Youdon index was 0.30, the sensitivity was 75.7%, and the specificity was 54.10%.  Conclusions   In CAPD patients, serum phosphorus level affects general cognition of the patients, and hyperphosphatemia is an independent risk factor for cognitive impairment in CAPD patients. If serum phosphorus level increases to >1.66 mmol/L, the risk of cognitive impairment increases significantly.

Key words: Peritoneal dialysis, Cognitive impairment, Hyperphosphatemia, Abnormal calcium and phosphorus metabolism