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Kidney Week

Abstract: PO0540

Predictive Value of Urine Osmolal Gap and Urine Anion Gap in CKD Progression

Session Information

Category: CKD (Non-Dialysis)

  • 2102 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Kim, Hyung Duk, Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea (the Republic of)
  • Park, Cheol Whee, Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea (the Republic of)
Background

Metabolic acidosis is the major complication of chronic kidney disease (CKD) and associated with poor clinical outcome. Impaired renal ammonium excretion in CKD lead to metabolic acidosis. The urinary anion gap (UAG) and urinary osmolal gap (UOG) have been used to estimate urinary ammonium excretion because of the limitation of clinical application of direct ammonium measurement. We sought to determine whether UAG and UOG predict progression of CKD.

Methods

185 patients with Stage II-V CKD were prospectively followed up at Catholic Medical College Multicenter Native Kidney Biopsy Cohort. 24-hour urine chemistry was measured at baseline. Routine laboratory test results were obtained at baseline and 1 year after enrollment. UAG and UOG were calculated using 24-hour urine chemistry results. Estimated GFR was calculated with CKD-EPI equation.

Results

Baseline characteristics are shown in Table 1.
Positive association between UOG and decline of renal function was observed (Figure 1). The line indicates the regression line for the relation between decline of renal function and urine osmolal gap; R = 0.035, β = 0.003 (P = 0.011).

Conclusion

UAG and UOG predict decline in renal function in CKD patients. Further studies are required to determine the direct correlation between UAG and UOG and urinary ammonium excretion.

Figure1

Table1.