Ageing of patients on chronic dialysis: effects on mortality--a 12-year study

During the last few decades the mean age of subjects on chronic dialysis (CD) significantly increased. The effects of these changes on mortality rates, causes of death, early and long-term predictors for mortality have not yet been clarified. We analysed this issue through a study performed over a period of 12 years.

We studied 8977 patients enrolled on the Lazio Dialysis Registry (Italy) in 1995-2006. We analysed annual mortality rates, causes of death, probability and determinants of the survival.

The overall mortality rate was 14.6 deaths (95% CI: 14.2-14.9) per 100 person-years on CD, remaining essentially unchanged over the 12-year period, despite a 5-year increase in the median age. A reduction in mortality was found for patients >74 years from 29.8 (95% CI: 24.8-34.9) in 1995 to 22.5 (95% CI: 20.0-25.1) in 2006. No statistically significant differences were found over time in annual mortality rates by cause of death. The probability of survival was 0.86 1 year after starting dialysis and 0.33 after 12 years. We found a higher association between haematocrit levels, serum albumin, self-sufficiency and survival within 1 year of dialysis and between diabetes and survival after 1 year.

The finding that the mortality rate of CD patients did not change over the last 12 years, despite concomitant and significant ageing of patients, supports the public health policy of providing CD to very old subjects. The identification of the clinical factors that predict survival underlines the role of clinicians in preventing and treating these conditions after the start of CD.