HYPERTENSION AND RENAL DIALYSIS

Hypertension And Renal Dialysis

Hypertension and Renal Dialysis: Concept Analysis on Compliance

Introduction

Hypertension, or perhaps more accurately high blood pressure, plays a pivotal role in the progression of renal failure. The dichotomy of “hypertension” and “normotension” fails to recognise that the risks of adverse cardiovascular and renal events are directly related to increasing levels of blood pressure, even within the “normotensive” range and that blood pressure lowering may benefit high-risk patients (particularly those with renal disease) who are not “hypertensive” by conventional definition.

“Increasingly the very terms hypertension, hyperglycaemia and hypercholesterolaemia will probably disappear, as the focus moves from treating a theoretically decided cut-off point towards managing continuous distributions of risk”. With that caveat, this article will consider

the prevalence of hypertension in renal disease and renal failure,

the role of hypertension as a determinant of cardiovascular morbidity and mortality in renal failure,

hypertension as both cause and consequence of renal disease,

hypertension in the progression of experimental renal disease,

hypertension in the progression of human renal failure and renal disease and

the options for treatment.

1. Prevalence of Hypertension in Renal Disease

Richard Bright was the first to recognise the association between hypertension and renal disease. He noted, “The hypertrophy of the heart seems in some degree to have kept pace with the advance of the disease in the kidneys”.3 This was initially documented by Volhard and Fahr.4 Hypertension is a common presentation of kidney disease and mandates careful urine examination, including microscopy. Virtually all forms of renal disease can cause hypertension, particularly in the presence of renal impairment, although hypertension is more frequent in vasculitis and glomerulonephritis than in interstitial disease. Primary renal disease leads to some 3% to 4% of hypertension in population studies and renovascular disease to around 1%. Hypertension is the rule in patients with end-stage renal failure (ESRF), some 80% to 90% of whom are hypertensive when presenting for dialysis. Globally, diabetic nephropathy has overtaken glomerulonephritis as the leading cause of end-stage disease. The prevalence of hypertensive nephropathy as a cause of ESRF depends on the population studied and the extent to which investigation for underlying causes is pursued.

2. Hypertension and Cardiovascular Morbidity/ Mortality in Renal Failure

Renal disease, particularly diabetic nephropathy, is a predictor of major cardiovascular disease (CVD) events. In Australia, more than half the patients with ESRF die from a cardiac or vascular event, and identification and treatment of hypertension and other cardiovascular risk factors is imperative. In Western countries, cardiac mortality for dialysis patients is 10- to 20-fold that of the general population. Similarly, the presence of proteinuria is associated with a markedly increased risk of CVD in hypertensives, and also in those with high CVD risk. Smoking is also important in this context. Not only is it a powerful risk factor for CVD, but it accelerates progression of renal disease and is thus one of the most important remediable risk factors. Obesity is another independent risk factor for CVD, renal disease and for ...