MO101ASSESSING EARLY RENAL INVOLVEMENT IN ESSENTIAL HYPERTENSION BY MEASURING URINARY ALBUMIN AND UROMODULIN EXCRETION

Abstract

Abstract Background and Aims Kidneys are target organs in hypertension. Hypertensive damage results in glomerular as well as tubular dysfunction. Albuminuria is a known marker of glomerular damage. Whereas, urinary uromodulin is increasingly considered as potential biomarker of early tubular dysfunction. The aim of this study was to identify the pattern of early renal involvement based on glomerular and tubular function assessment by measuring urinary albumin and uromodulin in hypertensive patients Method In this cross-sectional study 122 hypertensive subjects with age>30 years, duration of hypertension <5years, without accelerated or malignant BP, absence of dipstick proteinuria and eGFR>60ml/min. Subjects with possibility of secondary hypertension were excluded. There were also 33 normotensive volunteers included as healthy referents. Morning spot urine for albumin-creatinine ratio (ACR mg/g), urine uromodulin-creatinine ratio (urUMODµg/g), urinary sodium-creatinine ratio (mEq/g) and potassium-creatinine ratio (mEq/g) were measured in single urine sample. Urine uromodulin was measured by ELISA method. Results The hypertensive and healthy subjects were matched for age 48±11 vs. 47±11, years (P=NS). The systolic BP was 145±15 vs. 112±12 mmHg and diastolic BP 86±9 vs. 70±8 mmHg; (p<0.001) and the mean ACR was 29±65 vs. 5.6±2.7 mg/g, (p<0.001) respectively. Around 20% hypertensives had albuminuria. Urinary potassium excretion was lower in hypertensives (51±31 vs. 69±31, mEq/g; p<0.02). The median urUMOD in hypertensive subjects was 3.38 (1.73-9.06) and in normotensives 3.85(2.28-5.69) µg/g (P=NS).Multivariate analysis showed significant inverse association between diastolic blood pressure and urinary uromodulin excretion. An urURMOD cut-off of 2.9 (25th percentile in normotensives) showed eGFR, urinary sodium & potassium excretions were significantly lower at low uromodulin cut-off and this was seen in38%subjects. Conclusion The glomerular involvement was found in 20% hypertensives as evidenced by albuminuria. In general urinary uromodulin level was not different between hypertensive and normotensive subjects. Association of low uromodulin cut-off with lower eGFR, Na+ and K+ excretion indicates simultaneous tubule glomerular involvement in 38%.