Long-term follow-up of Argentinean patients with hemolytic uremic syndrome who had not undergone dialysis

Abstract

We examined the records of patients with hemolytic uremic syndrome, who had not undergone dialysis during the acute stage, with the aims of evaluating: (1) the outcome after at least 5 years of follow-up; (2) the value of peak serum creatinine as a prognostic marker; (3) the relationship between outcome and time to normalization of renal function. From 1968 to 2000, 1,179 patients were assisted. Forty-two patients (3.6%) died during the acute stage, 478 patients (40.5%) required dialysis and 659 patients (55.9%) did not undergo dialysis; 529 non-dialysis patients were lost to follow-up. The remaining 130 patients were classified into four groups: group I, complete recovery; group II, with two subgroups, IIa, microalbuminuria, and IIb, proteinuria and/or high blood pressure, both with normal renal function; group III, chronic renal failure; and group IV, end-stage renal disease. We analyzed the relationship between final outcome and: (1) peak creatinine (the highest of at least two determinations) during the acute stage and (2) time to normalization of urea and/or creatinine after the acute stage. After a mean follow-up time of 147.1 months (range 60-362 months), group I had 83 patients (63.9%), group IIa had 27 (20.8%), group IIb had 15 (11.5%) and group III had 5 (3.8%). The value of peak serum creatinine concentration was available for 57 patients. On the last clinical visit, eight out of 26 (30.7%) patients with peak serum creatinine equal to or higher than 1.5 mg/dl were in groups IIb and III versus one out of 31 (3.2%) patients with lower values (P < or = 0.007). Finally, six out of 28 patients (21%) whose renal function had normalized after 15 days from diagnosis were in groups IIb-III versus 8/82 (9.7%) whose renal function had normalized within 15 days (P = 0.18). After a mean period of follow-up of 12 years, 15% of a selected patient group had developed proteinuria, high blood pressure or chronic renal failure, and 21% had developed microalbuminuria. Peak serum creatinine during the acute stage was useful as a prognostic indicator. Patients whose renal function required more time to normalize did not have a worse outcome.