Renal Disease

Introduction

What is renal disease?

Renal disease is disease of the kidney. Kidney function is essential for life. If the kidneys fail then the body is unable to excrete certain waste products, excess water and salts, and is unable to control the body’s acidity leading to death.

Chronic renal failure (CRF) is a gradual and progressive loss of kidney function. End stage renal failure (ESRF) is an irreversible, long-term condition in which the kidneys fail and renal replacement therapy (RRT) – treatment to augment or replace the function of the failing kidneys – is required to maintain life. Renal disease appears less common in the UK than in the USA, in 2001, for example:

  • Prevalence was 566 per million population in the UK2 compared to 1,403 per million population in the USA; and
  • Incidence rate was 93 per million population in the UK2 compared to 336 per million population in the USA.

The acceptance rate onto renal replacement therapy (RRT) is a reflection of the incidence of end stage renal failure (ESRF). In the UK, this has risen from 20 per million population in 1980 to 101 per million population in 2002.

Prediction modelling by the UK Renal Registry suggests an increase in the numbers of patients on RRT for the next 20 years - probably to an annual incidence of about 100-110 per million population - when the numbers should stabilise. Prevalence will therefore also increase.

Factors affecting the level of renal disease level in a population

The level of renal disease in a population is influenced by a number of key factors in the population. The incidence of renal disease is higher in those of a South Asian and African Caribbean descent. Patients with high blood pressure and diabetes, which is increasing, also have a higher incidence of renal disease. Patients who have had renal disease in the past are at higher risk of developing renal failure.

The incidence of renal disease rises with increasing age, the incidence is thus higher in older populations.

Population levels of renal disease appear lower in Europe than in the USA5,6,7,8 with the UK having a lower treatment rate than much of the rest of Europe. The length of time of progression of chronic renal failure to end stage renal failure (ESRF) is very variable. Early intervention may slow or halt the progression of chronic renal failure (CRF)9,10. Key factors leading to the development of chronic renal failure are:

  • Diabetic nephropathy;
  • Hypertensive vascular disease; and
  • Glomerular disorders.

Regular assessment of at risk patients is important. Persistent high blood pressure and heavy proteinuria are strong predictors of progression of chronic renal failure. The use of good control of blood pressure lowering, good diabetes management, ACE inhibition and the avoidance of nephrotoxins may slow the decline of renal function.

Ethnicity

Renal disease is more common in people of Asian and African Caribbean decent with acceptance rates to renal replacement therapy which are four times higher than in Caucasians12,13.

Age and sex

There is a steep rise in acceptance on to renal replacement therapy with age12. Much of the increase in RRT over the last 20 years is due to the increased use of RRT in the over 65 population14,15. The increase in age of patients will lead to an associated increase in co-morbidity. Incidence of RRT is higher in men compared to women, with a ratio of about 1.5:12.

Deprivation

Incidence of RRT appears higher in more deprived areas (using Townsend score)4. In part, this may be due to patients on RRT from ethnic minorities being from more deprived areas. Patients from the deprived areas are younger, have more co-morbid conditions, and have poorer 1 year survival which can be explained by cardiovascular co-morbidity.