Intradialytic hypertension: prevalence, characteristics and associated factors in chronic hemodialysis patients at Kenyatta National Hospital Renal Unit.

Abstract

BACKGROUND. End Stage Renal Disease (ESRD) is increasingly being diagnosed in our set up with a number of patients being put on haemodialysis. These patients have an age adjusted mortality rate of 3-10 times that of the general population. Cardiovascular causes account for more than 50% of death intra dialysis. Intradialytic Hypertension, defined as an increase in systolic blood pressure by at least 10 mmHg from pre to post haemodialysis readings in a minimum of four out of six consecutive dialysis sessions is recognized as an independent cardiovascular risk factor. Despite cardiovascular causes accounting for more than 50% of death intra dialysis and Intradialytic Hypertension being an independent cardiovascular risk factor, there is no local data on its prevalence, patient characteristics and associated factors. This study was meant to provide us with the information that we hope will be used to improve patient outcome on haemodialysis and decrease mortality at the renal unit. OBJECTIVES. The aim of this study was to determine the prevalence of Intradialytic Hypertension in End Stage Renal Disease patients undergoing haemodialysis at Kenyatta National Hospital Renal Unit. The secondary objective was to compare selected patients’ characteristics and associated factors between those with and without IDH. Page 15 | METHODOLOGY. This was a cross sectional study done at Kenyatta National Hospital (KNH) Renal Unit over a period of 3 weeks. The study population were adults over 18 years on maintenance haemodialysis and who were willing to provide a written consent. All those who met the inclusion criteria were enrolled. Blood pressure was measured using BP machines of the Omron ®/Spengler ® types for 6 consecutive dialysis sessions (Pre and Post dialysis) on each of the participants. The fluid status was assessed at the beginning of the study using a Bio Impedance Spectroscopy whose data was analysed using the BC4 software. All those who were recruited had blood samples drawn at the beginning of the study for analysis of serum electrolytes and haemoglobin level at the renal lab in KNH. All data was analysed using SPSS. The prevalence of Intradialytic Hypertension (IDH) was calculated, Chi square test was used to test for association between IDH and associated factors with P value and Confidence intervals being calculated where necessary. RESULTS. Our study involved 512 haemodialysis sessions in 86 Chronic Kidney Disease patients with a mean age of 47.3±13.5 years and a sex ratio (M/F) of 1.5:1. The mean duration of dialysis was 6 months to 1 year. The average haemoglobin level was 8.6±1.9g/dl. The mean sodium concentration pre dialysis was 135.6±6.7mmol with a gradient of 4.4±6.7 mmols while that for potassium was 4.7±0.9mmols with a gradient of -2.9±1.1mmols. More than half [45(52.3%)] of the study participants had gross fluid overload with an average hydration status pre dialysis of 14.8±7.3%. Most of the study participants were on two antihypertensive medications with CCBS (93.3 %) Page 16 | being the drug of choice in our set up. The prevalence of IDH was 51.2%. Factors found to affect IDH in our set up were high pulse pressure and high SBP. CONCLUSION. IDH is often neglected despite it being recognized for many years, our study clearly shows that it is common in our cohort of haemodialysis patients with most of them having gross fluid overload. Its management is essential and should possibly incorporate adequate management of fluid status in these patients.