Risk factors for developing severe clinical course in HUS patients: a national survey in Japan

Background: Hemolytic uremic syndrome (HUS) is characterized by acute renal failure, thrombocytopenia and hemolytic anemia. Cases accompanied by prodromal gastrointestinal tract symptoms are referred to as typical HUS. Some severe HUS patients require dialysis or develop central nervous system (CNS) disorders after the onset of HUS. Methods: Patients who developed typical HUS in 2001 and 2002 in Japan, 127 in all, were the study subjects. To identify the risk factors for the development of a severe clinical course, clinical and laboratory data were analyzed on logistic regression. Results: Two of the 127 patients died (1.6%): one from acute cardiac failure and the other from a CNS disorder. Thirty-five patients required dialysis (28%) and 30 had CNS symptoms (24%). Multivariate analysis indicated that the risk factors for need for dialysis were serum sodium and alanine aminotransferase (ALT) levels of ≤130 mEq/L and ≥70 IU/L, respectively, at the onset of HUS and those for developing CNS disorders were dialysis and C-reactive protein (CRP) ≥5.0 mg/dL at the onset of HUS. Conclusions: Because patients with these risk factors, such as low serum sodium, high ALT or high CRP levels, may require dialysis or develop CNS disorders, they should be treated carefully in the early stage of HUS.