Hemodialysis-specific factors associated with salivary flow rates.

Abstract

The saliva is important to maintain the integrity of tissues and teeth, besides having microbial activity. Hemodialysis (HD) patients usually have reduced salivary flow rate (SFR) and are exposed to all its associated complications. The aim of the present study was to identify HD-related factors associated with reduced SFR. A cross-sectional study was performed with maintenance HD patients. Stimulated whole saliva was collected before and after HD. Xerostomia was assessed through the validated xerostomia inventory and thirst through the dialysis thirst inventory. Parameters of dental health status were obtained by the decayed, missed, and filled teeth index and community periodontal index. One hundred twenty-eight patients (66 males) participated in this study. Stimulated SFR before HD was 0.38 ± 0.28 mL/min. In univariate analysis and after adjusting for several factors, serum urea before HD session, serum intact parathormone (iPTH), calcium-phosphorus product (Ca×Pi), serum ferritin, and number of medications were negatively correlated with SFR in univariate analysis. Moreover, patients taking sevelamer had reduced SFR in comparison with those not receiving it (SFR 0.32 ± 0.19 vs. 0.44 ± 0.23 mL/min, P = 0.003). At multivariate analysis, including dialysis and nondialysis-related factors, age, elevated pre-HD serum urea, higher Ca×Pi product, higher iPTH, and sevelamer use remained as factors that were independently associated with a reduced SFR. After dialysis, there was a significant increment in SFR (0.39 ± 0.28 vs. 0.60 ± 0.34 mL/min, P < 0.001). Several HD-related features were associated with reduced SFR, including serum urea, sevelamer use, and bone and mineral disorders markers.