Clinical Characteristics and Significance of Asymptomatic Bacteriuria in Hemodialysis Patients

BACKGROUND: High prevalence of asymptomatic bacteriuria (ASB) was reported in dialysis patients. Meanwhile, chronic inflammation, including chronic infection, was widely proved to be one of the most important risk factors of morbidity and mortality in maintenance hemodialysis (HD) patients. The aim of this study was to clarify the clinical implications of ASB in long-term HD patients via analyzing its epidemiology, microbiology, relationship with pyuria, predisposing factors and impact on inflammatory state.METHODS: Forty-two patients on stable long-term HD without symptoms of urinary tract infection (UTI) were included in this study. Two specimens of clean-catch urine were collected separately for general analysis and bacterial culture. Baseline characteristics, hemogram, biochemical parameters and inflammatory markers, albumin and C-reactive protein (CRP), between patients with ASB (＞ 1×10^5 colony-forming units per mL of a single microorganism) and without ASB were compared, Moreover, in view of the close association between ASB and pyuria (＞ 10 white cell count per high-power field), the prevalence, predisposing factors, predictability of ASB and chronic inflammatory activity of patients with pyuria were also examined.RESULTS: Twenty-nine percent (12 in 42) of HD patients had significant single bacteriuria. E. coli was the most common bacterium. All of the patients with ASB also had pyuria. The prevalence rate of ASB was markedly associated with old age (P=0.008) and diabetes (P=0.001). Comparison between patients with and without ASB showed no difference in albumin and CRP level. Moreover, 50 % (21 in 42) of patients revealed positive pyuria results. Among the 21 patients, 12 (57%) indicated ASB. The predisposing factors included decreased daily urine amount (P=0.006) and diabetes (P=0.005). As in ASB, no difference in inflammatory markers was found when comparing between patients with and without pyuira.CONCLUSION: In chronic HD patients, ASB was common and pyuria was a good predictor. The major risk factors were old age and diabetes. Even though patients with ASB or pyuria revealed a trend toward worse inflammatory state, the difference showed no statistical significance.