Analysis of 24-hour urinary sodium excretion and its corelation with 24-hour blood pressure in healthy subjects, chronic kidney disease patients and maintenance dialysis patients

Abstract

Background: Hypertension is one of the most important modifiable risk factors for progression of CKD and
also cardiovascular events in CKD patients. Accurate blood pressure (BP) measurement aids in the diagnosis
and treatment of hypertension. ABPM has been successful in identifying hypertensive CKD patients at increased
risk. The present study investigated correlation of 24-hour urinary sodium excretion and 24-hour ambulatory
blood pressure in various stages of CKD patients and healthy population.
Materials & Methods: 100 patients fulfilling the criteria were recruited from the nephrology wards. Patients
were divided into 3 groups. Group 1: healthy subjects, Group 2: chronic kidney disease patients not on dialysis
and Group 3: maintenance dialysis patients. Data on medical history, laboratory test results and current therapy
were collected. The24-hourambulatorybloodpressure and 24-hour urine sodiumofallpatients were measured.24-
hour ambulatory blood pressure of all patients measured with automated, programmable, oscillometric
ambulatory blood pressure monitor with LCD display device named ABPM – 05, manufactured by Meditech
Ltd. 1184 Budapest, MikszáthKálmánutca 24, Hungary. ABPM was obtained while patient was receiving
regular antihypertensive therapy. Measurement of 24-hour urine sodium was done by Indirect Integrated
Multisensor Technology (IMT) by Ion Selective Electrode method. Results thus obtained were assessed
statistically.
Results: The mean 24-hour urine sodium (mmol/day) was 112.5 ± 44.6 in group I, 107.7 ± 61.9 in group II and
74.8 ± 26.1 in group III, eGFR (ml/min/1.73 m2) was 102.8 ± 20.9 in group I, 34.6 ± 32.4 in group II and 6.6 ±
4.2 in group III. SBP (mm Hg) was 125 ± 12.5 in group I, 137.6 ± 20.7 in group II and 146.7 ± 18.7 in group III.
DBP (mm Hg) was 76.7 ± 7.3 in group I, 82 ± 13.2 in group II and 88.3 ± 13.1 in group III. 24-hours mean
MAP (mmHg) was 92.8 ± 8.5 in group I, 100.5 ± 14.2 in group II and 107.8 ± 13.9 in group III.
inCKDpopulation,thereisnocorrelation of 24-hour blood pressure with 24-hour urinary sodium excretion
Conclusion: There is a positive but not statistically significant correlation between 24-
hoururinarysodiumandmeanSBPinCKDpatientsnotondialysis.