Kidney transplant triples life expectancy in end-stage renal failure

Kidney transplant triples life expectancy in end-stage renal failure

Pam G Harrison, Mhs
MEDSCAPE

May 10, 2005

Edinburgh, Scotland - A successful kidney transplant triples life expectancy in end-stage renal failure compared with that expected in patients remaining on dialysis, according to long-term data from Scotland.[1] Data from the Scottish National Health Service showed that projected life expectancy in patients receiving a cadaveric kidney was 17.19 years compared with only 5.84 years for those who remained on dialysis.

"We knew from US data that the life-expectancy rate is double with transplantation compared with dialysis, so we were expecting a similar survival advantage," Dr Gabriel Oniscu (The Royal Infirmary of Edinburgh, UK) told renalwire. "The fact that our survival advantage was actually better is obviously a bonus for us, so it was a very interesting finding and we were very pleased with it."

Findings from the study were published online April 27, 2005 in the Journal of the American Society of Nephrology.

Transplant vs dialysis

Oniscu and colleagues carried out a long-term survival assessment of 1732 adults listed for kidney transplantation in Scotland between January 1 and December 31, 1989. Of these, 1095 (63%) received a cadaveric kidney transplant by the end of December 2000. The effect of transplantation on survival was reported as a relative risk of death, which was the rate of death among transplant recipients relative to dialysis patients on the waiting list.

Crude mortality rates for transplant recipients were 4.13 per 100 patient-years of follow-up vs 9.02 per 100 patient-years of follow-up for those who remained on dialysis. The relative risk of death between the two treatment groups depended on the length of follow-up.

Without adjusting for differences in the risk profile between the two treatment groups, the relative risk of mortality from transplant to 30 days was slightly though not significantly higher in the transplant-recipient group vs dialysis controls. However, between 31 and 365 days, the relative risk of mortality was 33% lower in transplant recipients. After 365 days, the relative risk of mortality was 68% lower for transplant recipients compared with those who remained on dialysis, with both the latter findings reaching statistical significance.
Relative mortality risk in patients receiving transplant vs those remaining on dialysis (unadjusted for comorbidity)

Time point Relative risk (95% CI)
30 days 1.35 (0.63-2.86)
31-365 days 0.67 (0.48-0.95)
>365 days 0.32 (0.25-0.40)

Differences did exist between patients who received a transplant and those who remained on dialysis. For example, those remaining on dialysis had a significantly higher prevalence of both diabetes and multisystem diseases compared with transplant recipients. Dialysis patients also had twice the incidence of myocardial infarction and angina compared with those who received a transplant, and the prevalence of cerebrovascular and gastrointestinal disorders was also higher in the dialysis group.

However, after adjusting for discrepancies in risk profile, there was still a 50% lower relative risk of mortality between 31 to 365 days in favor of transplantation. At 18 months, the relative risk of mortality was 82% lower among transplant recipients compared with patients on dialysis, the authors add. In the adjusted model, mortality under 30 days was lower, although still nonsignificantly, in transplant patients compared with those who remained on dialysis.
Relative mortality risk in patients receiving transplant vs those remaining on dialysis (adjusted for comorbidity)

Time point Relative risk (95% CI)
30 days 0.91 (0.22-3.70)
31-365 days 0.50 (0.28-0.90)
>365 days 0.28 (0.20-0.39)

Benefit pronounced in diabetes

Investigators also found that the relative risk of death following transplantation was significantly reduced across all age groups. "The greatest benefit was achieved in patients aged 50 to 59 years," they state. "[But] this lower long-term risk of death was present in all patients undergoing transplantation, irrespective of their age group or primary renal disease." Even patients with diabetes had a 67% lower risk of mortality at one year compared with those who remained on dialysis.

The take-home message here is that people should provide a kidney for a loved one if they need one because it really offers a great hope for [the recipient].

Indeed, transplantation in patients with diabetes led to the highest proportional increase in lifespan compared with all other groups, even though they had the shortest overall life expectancy, the authors observe. Transplantation also doubled life expectancy in patients 65 years of age and older compared with that seen in the same age group who remained on dialysis. These findings suggest that "we should judge the elderly by their biological rather than their chronological age," Oniscu said.

Oniscu added that because their study clearly showed that transplantation is superior to dialysis, the public should be encouraged to donate a kidney should the need arise. "This paper was based on cadaveric donors only, but we know that survival is significantly better with live donors. So the take-home message here is that people should provide a kidney for a loved one if they need one because it really offers a great hope for [the recipient]."

Medscape Medical News 2005. © 2005 Medscape

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