Saliva Urea Nitrogen Continuously Reflects Blood Urea Nitrogen after Acute Kidney Injury Diagnosis and Management: Longitudinal Observational Data from a Collaborative, International, Prospective, Multicenter Study.

BACKGROUND: Acute kidney injury (AKI) is a growing global concern and often reversible. Saliva urea nitrogen (SUN) measured by a dipstick may allow rapid diagnosis. We studied longitudinal agreement between SUN and blood urea nitrogen (BUN) and the diagnostic performance of both. METHODS: Agreement between SUN and BUN and diagnostic performance to diagnose AKI severity in AKI patients in the United States and Brazil were studied. Bland-Altman analysis and linear mixed effects models were employed to test the agreement between SUN and BUN. Receiver operating characteristics statistics were used to test the diagnostic performance to diagnose AKI severity. RESULTS: We found an underestimation of BUN by SUN, decreasing with increasing BUN levels in 37 studied patients, consistent on all observation days. The diagnostic performance of SUN (AUC 0.81, 95% CI 0.63-0.98) was comparable to BUN (AUC 0.85, 95% CI 0.71-0.98). CONCLUSION: SUN reflects BUN especially in severe AKI. It also allows monitoring treatment responses. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=445041.

Metabolic effects of dialyzate glucose in chronic hemodialysis: results from a prospective, randomized crossover trial.

BACKGROUND: There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD) and 100 and 200 mg/dL (G100 and G200) are frequently used. G200 may result in diffusive glucose flux into the patient, with consequent hyperglycemia and hyperinsulinism, and electrolyte alterations, in particular potassium (K) and phosphorus (P). This trial compared metabolic effects of G100 versus G200. METHODS: Chronic HD patients participated in this randomized, single masked, controlled crossover trial (www.clinicaltrials.gov: #NCT00618033) consisting of two consecutive 3-week segments with G100 and G200, respectively. Intradialytic serum glucose (SG) and insulin concentrations (SI) were measured at 0, 30, 60, 120, 180, 240 min and immediately post-HD; P and K were measured at 0, 120, 180 min and post-HD. Hypoglycemia was defined as an SG<70 mg/dL. Mean SG and SI were computed as area under the curve divided by treatment time. RESULTS: Fourteen diabetic and 15 non-diabetic subjects were studied. SG was significantly higher with G200 as compared to G100, both in diabetic {G200: 192.8±48.1 mg/dL; G100: 154.0±27.3 mg/dL; difference 38.8 [95% confidence interval (CI): 21.2-56.4] mg/dL; P<0.001} and non-diabetic subjects [G200: 127.0±11.2 mg/dL; G100 106.5±10.8 mg/dL; difference 20.6 (95% CI: 15.3-25.9) mg/dL; P<0.001]. SI was significantly higher with G200 in non-diabetic subjects. Frequency of hypoglycemia, P and K serum levels, interdialytic weight gain and adverse intradialytic events did not differ significantly between G100 and G200. CONCLUSION: G200 may exert unfavorable metabolic effects in chronic HD patients, in particular hyperglycemia and hyperinsulinism, the latter in non-diabetic subjects.