Non-CV Mortality Also Important in Dialysis Patients

Shelley Wood

October 29, 2009

October 28, 2009 (Leiden, the Netherlands) — Contrary to popular belief, the increased risk of death among people starting dialysis is not necessarily driven by an excess risk of cardiovascular mortality, a new study suggests [1]. The finding calls into question the emphasis that is placed on preventing cardiovascular events in this group, at least at the expense of remaining vigilant about other potential causes of mortality, Dinanda J de Jager (Leiden University Medical Center, the Netherlands) and colleagues conclude in the October 28, 2009 issue of the Journal of the American Medical Association.

Commenting on the findings to heartwire , de Jager emphasized that most research has in fact shown that both cardiovascular and noncardiovascular mortality rates are high in dialysis patients and, indeed, that the causes of death in these patients actually share some--but not all--of the same risk factors.

"However, since the belief that dialysis patients are at high cardiovascular mortality risk is so strong, many researchers and doctors simply overlook these facts; they stress the importance of prevention of cardiovascular mortality, but they forget the increased noncardiovascular mortality risk," she told heartwire . "In our paper, we showed, with a relatively easy and straightforward calculation, that we really should change our attitude: we should not only aim at the prevention of cardiovascular mortality in dialysis patients, but also noncardiovascular mortality."

Early Risks in Dialysis Treatment

For their study, de Jager et al reviewed age-stratified mortality among 123 407 European adults who started dialysis between 1994 and 2006, comparing causes of death in this group with those in the general population. They found that overall mortality rates were indeed higher among dialysis patients than those of the general public, as were both cardiovascular mortality rates and noncardiovascular mortality rates, analyzed separately. But importantly, the rate of noncardiovascular deaths was actually higher than that of cardiovascular deaths in the dialysis group: 50 per 1000 person-years, as compared with 38 per 1000 person-years for cardiovascular deaths.

"The present study showed that the proportion of cardiovascular and noncardiovascular mortality in patients starting dialysis was approximately 44% . . . and 56%," respectively, the authors write. While it's possible that their analysis underestimated cardiovascular deaths or that causes of death were not appropriately listed at the time, the authors say the key message from their analysis is that both kinds of mortality are important considerations for patients starting dialysis.

"The present study shows that cardiovascular and noncardiovascular mortality are equally increased during the first three years of dialysis, compared with the general population," the authors conclude. "This implies that the importance of noncardiovascular mortality in patients receiving dialysis has generally been underestimated. Therefore, research should focus more on methods to prevent noncardiovascular mortality."

To heartwire , de Jager said that the findings do not imply any changes in practice for cardiologists. "Dialysis patients do have cardiovascular problems, for sure!" she said. "The only thing we wanted to show to the world is that we should not forget that dialysis patients also have noncardiovascular problems, which are dangerous."

The implications for cardiologists might be that they should be more aware of potential problems arising outside of the usual cardiovascular suspects, including such risks as infections, she added.