Predictive significance of predialysis plasma osmolality for frequent intradialytic hypotension in elders on maintenance hemodialysis

Objective To explore the predictive value of predialysis plasma osmolality for frequent intradialytic hypotension (IDH) in elders on maintenance hemodialysis (MHD).

Methods According to whether or not there was frequent IDH, 301 MHD elders were assigned into two groups of control (n=257) and frequent IDH (n=44). General profiles, laboratory parameters and cardiac B-ultrasound examinations were recorded. The risk factors for frequent IDH were identified by multivariate Logistic regression. Receiver operating characteristic (ROC) curve was plotted for exploring the predictive efficacy of predialysis plasma osmolality for frequent IDH.

Results As compared with control group, ultrafiltration rate, parathyroid hormone (PTH) and predialysis plasma osmolality spiked obviously while hemoglobin, serum albumin (Alb), left ventricular ejection fraction (LVEF) and Kt/V declined markedly in frequent IDH group (all P<0.05). Multivariate analysis indicated that elevations of ultrafiltration rate (OR=1.24), PTH (OR=1.01) and predialysis plasma osmolality (OR=1.22) were risk factors for frequent IDH while elevations of Alb (OR=0.82) and LVEF (OR=0.73) were its protective factors. With an optimal cut-off value of 301.6 mOsm/(kg.H2O), area under the curve for predicting frequent IDH by predialysis plasma osmolality was 0.79 with a sensitivity of 58.5% and a specificity of 91.1%.

Conclusion Elders with an elevation of predialysis plasma osmolality are more susceptible to frequent IDH. They deserve a heightened attention.