Cytomegalovirus excretion as a predictor of cytomegalovirus disease after marrow transplantation: importance of cytomegalovirus viremia.

Cytomegalovirus (CMV) viremia and excretion from the oropharynx and urine were examined for their utility in predicting the development of CMV disease, including pneumonia and gastrointestinal disease, among 617 marrow allograft recipients. CMV viremia had a 60% and excretion from oropharynx or urine or viremia a 44% positive predictive value for the development of CMV disease. Viremia or excretion preceded disease onset by a median of 15 days among those in whom excretion occurred first. In stepwise time-dependent proportional hazards regression analyses, CMV viremia and positive serology before transplant were predictive for both CMV pneumonia and gastrointestinal disease. Oropharyngeal excretion was independently predictive for gastrointestinal disease but not pneumonia. Urinary excretion was not independently predictive. Acute graft-versus-host disease was predictive for pneumonia but not gastrointestinal disease. Thus use of CMV excretion, particularly viremia, as a marker to determine the initiation of antiviral chemotherapy could be effective in preventing progression of infection to serious disease. However, with standard virologic techniques this strategy would not be effective in patients (32% in this study) without CMV excretion detected before the onset of pneumonia or gastrointestinal disease.