"Our results show that the effect of hemoglobin variability on mortality, beyond the absolute level of hemoglobin, may not confer much additional risk, after adjusting for other illnesses and hospitalizations," comments David T. Gilbertson, Ph.D., of the Minneapolis Medical Research Foundation, Minneapolis, Minn.
Dr. Gilbertson and colleagues used data on nearly 160,000 dialysis patients to analyze the effects of variations in hemoglobin level on the risk of death. Patterns of hemoglobin variability during the first six months of 2004 were analyzed and compared with mortality rates over the subsequent six months.
In the study, patients who developed low hemoglobin levels during the monitoring period were at increased risk of death. This was true both for patients with temporary reductions in hemoglobin and those whose hemoglobin level was persistently low. This risk was considerably greater than any risk associated with fluctuations in hemoglobin levels.
On further analysis, the key risk factor seemed to be the amount of time spent with a low hemoglobin level — not the hemoglobin variations themselves. Patients who spent three months or longer with low hemoglobin levels had the highest mortality rates.
"A number of research groups have shown that variability of hemoglobin levels is very common in patients receiving dialysis for end-stage renal disease," says Dr. Gilbertson. "Low hemoglobin levels, which are an indication of anemia, have been shown to be associated with poor outcomes. It is relatively unknown whether fluctuations in hemoglobin levels add additional risk." If so, then more intensive treatment might be needed to keep hemoglobin levels within a relatively narrow range.
MEDICA.de; Quelle: American Society of Nephrology