POS-294 NEPHROLOGY REFERRAL SLOWS THE PROGRESSION OF CHRONIC KIDNEY DISEASE ESPECIALLY AMONG PATIENTS WITH PROTEINURIA OR ANEMIA: A SINGLE CENTER RETROSPECTIVE STUDY

Abstract

The Kidney Disease Improving Global Outcomes guidelines recommend nephrology referral when estimated glomerular filtration rate (eGFR) is less than 30 mL/min/1.73m2, and significant proteinuria or microscopic hematuria persist. However, this recommendation is based on specialist opinions and aimed at avoiding adverse outcomes of late referral. Which patients with chronic kidney disease are benefited from nephrology referral has not been elucidated. This is a retrospective cohort study. Inclusion criterion was patients who were referred to the nephrology clinic at Gamagori Municipal Hospital from April 2017 to March 2019. Exclusion criteria were patients with acute kidney injury, defined as annual decline of eGFR more than 20 mL/min/1.73m2, and patients on dialysis. The slopes of eGFR before and after nephrology referral were estimated and compared by mixed effects models. The data were adjusted for age, eGFR, the presence of diabetes, proteinuria (defined by urine dipstick protein 2+ or more), urine occult blood, hypoalbuminemia (defined by albumin level less than 3.5 g/dL), and anemia (defined by hemoglobin levels less than 10.5 g/dL). Interaction between time and referral status (before or after referral) was assessed and effect modifications (3-way interaction) by age, eGFR, the presence of diabetes, proteinuria, urine occult blood, hypoalbuminemia, and anemia were evaluated. Total of 343 patients met the inclusion criterion. Mean age was 69.6 (18.8), 54.4% were male, 26.8% were diabetics, median eGFR was 49.2 (23.3-69.5), and the proportions of patients with proteinuria and urine occult blood were 43.7 and 38.5%, respectively. The eGFR slope significantly improved from -2.52 (-3.02 to -2.02) to -1.26 (-2.01 to -0.51) mL/min/1.73m2/year after nephrology referral (p for interaction 0.001) (Figure 1). The improvement in eGFR slope was more prominent among those with proteinuria or anemia (p for 3-way interaction 0.04 and <0.001 after adjustment for covariates, respectively) (Figures 2-3). View Large Image Figure ViewerDownload Hi-res image Download (PPT) The effect modifications by eGFR, DM, and hypoalbuminemia were of borderline significance (p for 3-way interaction 0.06, 0.06, and 0.07, respectively). There were no effect modifications by age or urine occult blood (p for 3-way interaction 0.88 and 0.78, respectively). Nephrology referral slows the progression of chronic kidney disease especially among those with proteinuria or anemia, but not among those with urine occult blood. Inclusion of anemia as a criterion for nephrology referral in guidelines should be considered.