TTP and HUS are severe disorders characterized by microangiopathic hemolytic anemia and thrombocytopenia. Untreated, the short term mortality is estimated at 90%. Prognostic variables for predicting response and survival have been difficult to validate because of the relatively small sample sizes of previous analyses. We performed a retrospective cohort analysis on 126 consecutive patients with an established diagnosis of TTP-HUS treated principally with plasma exchange. These patients had been referred to the Sacramento Medical Foundation Blood Center and the University of California Davis Medical Center between 1978 and 1998. To standardize disease involvement, patients were assigned a previously described Clinical Severity Score (Rose, Am J Med 83:437, 1987) based on four clinical and laboratory parameters, if available, at the time of presentation. The Severity Score incorporates the neurologic, renal, and hematologic abnormalities and is the sum of all the parameters, with a range of 0-8 points. We also determined the effect of therapeutic plasma exchange on 30-day mortality, response rate, and overall survival. 122 patients (97%) received plasma exchange as principal treatment, with a mean of 9 exchanges and a mean cumulative infused volume of 43,040 ± 77,682 mL of fresh frozen plasma. There were 56% complete responders and 21% partial responders for an overall response proportion of 77%. Overall 30-day mortality was 10.3% (n=13). Relapse rate was 12.8%. Univariate analysis demonstrated that a higher Clinical Severity Score at the time of diagnosis increased the risk of 30-day mortality with an odds ratio of 2.5 and a p-value of 0.0067. In conclusion, we have confirmed that early, aggressive plasma exchange therapy results in both high response and survival rates in this large cohort of TTP-HUS patients. We have likewise shown that the Clinical Severity Score may be a useful prognostic variable in predicting 30-day mortality.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
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