Dimitrios G. Oreopoulos
Nada Dimkovic
Toronto Western Hospital,
University Health Network

Introduction
The elderly (>65 years) are the fastest growing group of patients who require dialysis. In 1988, of the more than four thousand new dialysis patients, one thousand nine hundred and fifty eight were 65 years or older, giving an approximate rate of 515 new patients per million members of the population.

Once an elderly patient has developed end-stage renal disease (ESRD), his/her therapeutic options become limited to the various modes of dialysis that are available and, to a lesser degree, to renal transplantation.

Here we should mention a word of caution with regards to using serum creatinine as a guide for the point at which to begin dialysis. Because of the decrease in muscle mass that is associated with age, serum creatinine is disproportionately low for the degree of renal failure. Rather than relying on serum creatinine, either a creatinine clearance, or the Cockroft-Gault formula should be used to assess the severity of renal failure.

Although renal transplantation may be successful in the elderly person with ESRD, and they may have renal graft and patient survival rates comparable to those of younger recipients, only a small percentage (0.5-3%) of these patients are undergoing transplant procedures. The main reason for this is the shortage of donor kidneys.

Canada's aging population has contributed to a substantial increase in dialysis use, according to figures released in August by the Canadian Institute for Health Information (CIHI). The prevalence rate for all patients on dialysis in Canada was 399.2 per million in 1997. This represents a 13.9% increase from 1996 and a 200% rise since 1981. "Elderly patients accounted for most of that increase," explained Dr. John Jeffery, an advisor to CIHI's Canadian Organ Replacement Register.

The increase in incidence of end stage renal disease (ESRD), the most severe form of kidney failure, was much greater for the elderly than for younger age groups. Between 1981 and 1997 the relative increase in ESRD incidence (per million population) was 244% for those aged 65 to 74 and 468% among those aged 75 and above. Canadians aged 45 to 64 experienced just a 71% relative increase during the same period.

"People aged 65 and older represented 23% of ESRD cases in 1981 when we began collecting these data," added Dr. Jeffery. "Our latest figures show that by 1997, the proportion had more than doubled to 48%."

Dialysis is a life-prolonging process for patients with ESRD; in most cases a kidney transplant is the most effective treatment. However, the proportion of transplants has been steadily decreasing. "This reflects a shortage of organ donations and the increasing percentage of ESRD patients who are elderly and less likely to be transplant candidates," says Daria Parsons of the CIHI.