Aims: Hemodialysis patients receiving intravenous iron and erythropoietin may develop greatly elevated ferritin levels. Both iron overload and inflammation may account for this hyperferritinemia. The aim of this study was to try to identify the cause of the high ferritin level among individual patients.
Methods: Sixty-seven chronic hemodialysis patients with ferritn levels < 700 microg/l were compared to 47 patients whose ferritin levels were > or = 700 microg/l. Clinical and laboratory data were collected and evaluated by cluster analysis which allowed patients to be placed into statistically dissimilar groups.
Results: The 47 high ferritin patients segregated into 3 clusters consisting of 28, 3, and 16 patients based on ferritin, zinc protoporphyrin, albumin, C-reactive protein, and hemoglobin. When contrasted with cluster 1, cluster 3 patients had higher levels of Zn-PP, CRP, and ferritin and lower levels of albumin and hemoglobin.
Conclusions: Utilizing these data and the results of many other studies, we conclude that, relative to cluster 1, cluster 3 patients had a more intense inflammatory response that blocked iron mobilization required for erythrocyte production. Cluster analysis appears to be a useful method of analyzing clinical data of relatively small patient population.