Pre-Dialysis Anemia Ups Mortality After Dialysis Start
Patients with vs without anemia prior to starting hemodialysis (HD) were more likely to die despite achieving target hemoglobin levels at month 4 after HD initiation.
Low hemoglobin levels at hemodialysis (HD) initiation are associated with an increased risk of death during the first year of HD, according to study findings presented at the 55th European Renal Association-European Dialysis and Transplant Association congress in Copenhagen, Denmark.
Angelo Karaboyas, MS, of Arbor Research Collaborative for Health, DOPPS, Ann Arbor, Michigan, and colleagues examined the association between hemoglobin measured within 30 days of starting HD (month 1) and mortality from month 4 through month 12 among 4461 HD patients with hemoglobin levels of 10 g/dL or higher at month 4. Study patients were from 21 countries and were part of phases 4–5 (2009–2015) of the Dialysis Outcomes and Practice Patterns Study (DOPPS).
At month 1, 80% of patients had hemoglobin levels below 11 g/dL and 53% had levels below 10 g/dL. Compared with patients who had hemoglobin levels below 11 g/dL, those with levels of 11 g/dL or higher at month 1 were older, more likely to be male, and had higher albumin and lower transferrin saturation, but did not have a lower burden of comorbidities, Dr Karaboyas' group reported.
Hemoglobin levels at month 1 were inversely associated with first-year mortality, despite minimal differences in hemoglobin levels at month 4, according to the investigators. In adjusted analyses, each 1 g/dL increase in hemoglobin was associated with a significant 11% decreased risk of first-year mortality.
Patients with lower hemoglobin levels at month 1 received greater doses of erythropoiesis-stimulating agents (ESAs) over the first 3 months of HD and achieved the largest hemoglobin increases over these 3 months, according to the investigators. In contrast, mean IV iron dose over the first 3 months varied much less by month 1 hemoglobin level. Additional adjustment for ESA and IV iron doses over the first 3 months of HD had minimal impact on mortality.
“Management of anemia before the start of HD may improve survival after dialysis start by avoiding the potential lingering harm of chronic anemia and/or avoiding high doses of ESA and IV iron in the early months of HD,” the investigators concluded in their study abstract.
“These are interesting preliminary findings from a well-regarded research group using DOPPS data,” commented James B. Wetmore, MD, of Hennepin County Medical Center in Minneapolis, Minnesota, who led a study showing decreased survival after HD initiation among patients who had anemia prior to starting HD but was not involved in the new study. “The findings appear to suggest that anemia prior to dialysis initiation, the presence of which may reflect both overall clinical status, such as concurrent illness or inflammation, and access to care, is associated with the clinical course after dialysis initiation. That is, there may be a ‘legacy effect' of pre-dialysis anemia and its management on survival after dialysis initiation.”
As with all such observational studies, Dr Wetmore cautioned, potential confounding is always an issue. “Are patients who are anemic also sicker in ways that non-anemic patients are not, and is it this underlying illness that is the real cause of increased mortality after dialysis initiation, rather than the anemia itself? It will be interesting to see the completion of this work and further analyses along these lines, as such work could help address the issue of how nephrologists should treat anemia in late-stage predialysis CKD.”
Karaboyas A, Morgenstern H, Pisoni RL, et al. Is low hemoglobin at hemodialysis initiation associated with first-year survival among patients treated to target levels soon after dialysis start? Data presented at the 55th European Renal Association-European Dialysis and Transplant Association congress in Copenhagen, Denmark, May 24–27. Abstract SP340.