FIRST YEAR SEROLOGIC RESPONSE TO TREATMENT FOR SYPHILIS - A MODEL FORPREDICTION OF SEROREVERSION

There is no straightforward test available, within weeks of treatment for syphilis, to assess adequacy of serologic response. We propose a m ethod to predict non-treponemal seroreversion based on short term resp onse. To develop and illustrate this method, we used data from 370 ind ividuals with infectious syphilis. Individual serologic response appea rs to be a linear function of(log) time, suggesting the possibility of using rapid plasma reagin titres recorded in the first few months aft er treatment to determine the slope of the linear treatment response l ine. The slope of the response line, during the first year after treat ment, is an important predictor of seroreversion but must be considere d in conjunction with pre-treatment titre. We recommend development of an action line be developed based on these variables. Such a line wou ld indicate the necessity for retreatment if the line plotted from the patient's first year response failed to fall below the action line. ( C) 1997 by John Wiley & Sons, Ltd.