Although maintenance dialysis prevents death from uremia, patient survival remains an important issue. Once renal replacement therapy is initiated, the range of the expected remaining life span in the United States Renal Data System report was approximately 8 years (varies with race) for dialysis patients aged 40 to 44, and approximately 4.5 years for those 60 to 64 years of age . These values in older patients are only slightly better than those in patients with lung cancer and are much worse than the general population (which is 30 to 40 years for those aged 40 to 44, and 17 to 22 years for individuals aged 60 to 64). Despite this, some evidence suggests that mortality rates among incident dialysis patients have decreased over the last few years, suggesting that improvements in therapy may provide beneficial results .
It is well established that inadequate dialysis is a contributor to lower overall survival. This has important implications since more intensive dialysis, particularly above a certain threshold value, may improve survival, possibly as with nocturnal hemodialysis.
Additional factors associated with the dialysis procedure may also correlate with decreased survival. As examples:
- Dialysis vintage is associated with an enhanced risk of death, with each year of dialysis treatment increasing the risk of death by approximately 6 percent .
- Potassium levels <4.0 or >5.6 mEq/L are associated with increased mortality in hemodialysis patients, compared with serum levels between 4.6 and 5.3 mEq/L .
- In the United States, some, but not all, studies have reported that mortality may be lower among dialysis patients being treated in not-for-profit facilities compared with those undergoing dialysis in for-profit facilities [4-8].
A review of those factors associated with mortality among dialysis patients, with an emphasis upon those characteristics related to dialysis itself, will be presented here.