Lack of clinical utility of cytomegalovirus blood and urine cultures in patients with HIV infection

* Objective: To determine the clinical significance of cytomegalovirus (CMV) blood and urine cultures in patients with human immunodeficiency virus (HIV) infection. * Design: Inception cohort of patients with HIV infection and CMV culture data. * Setting: Government referral-based research hospital. * Patients: A total of 322 HIV-infected patients who had a CMV blood culture and 293 HIV-infected patients who had a CMV urine culture within 7 days of a CD4 determination. * Measurements: Cytomegalovirus blood and urine culture results; circulating CD4 lymphocyte counts; pathologic or retinopathic findings of CMV disease. * Results: Nine of 26 patients (34.6%) with CMV viremia subsequently developed CMV end-organ disease compared with 11 of 74 (14.9%) patients without viremia, (difference, 19.7%; 95% CI, -0.3% to 39.7%). Fifteen of 47 patients (31.9%) with CMV viruria developed end-organ disease compared with 4 of 43 (9.3%) patients without viruria, (difference, 22.6%; CI, 6.7% to 38.5%). Cytomegalovirus culture positivity had poor predictive value for the subsequent development of end-organ disease (35% for viremia and 28% for viruria). Further, patients with proven end-organ disease were often not viremic (45%), but most were viruric (88%). Cytomegalovirus viremia did not correlate with the presence of either fever or weight loss in this patient group. Both blood culture positivity and urine culture positivity varied inversely with the CD4 count (P = 0.0001 for both associations). * Conclusions: The likelihood that a blood or urine culture will be positive in a patient with HIV infection correlates better with immunologic status than with current or future clinical status. Although the absence of CMV viruria may suggest that CMV disease is not present, CMV blood and urine cultures have poor diagnostic and predictive value and therefore should be used primarily for research purposes or drug susceptibility testing and not for making clinical decisions.
HIV-infected individuals who have a positive blood or urine culture for cytomegalovirus (CMV) may not be more likely to develop CMV end-organ disease than those who do not. End-organ diseases often caused by CMV in HIV-positive individuals include retinitis, enteritis and pneumonitis. Among 615 HIV-infected patients, 322 underwent a blood culture for CMV and 293 underwent a urine culture for CMV. Thirty-five percent of the patients with a positive blood culture for CMV subsequently developed CMV end-stage disease. Thirty-two percent of the patients with a positive urine culture developed CMV end-organ disease. Of the 29 patients who underwent a blood or urine test within seven days of developing CMV end-organ disease, 55% had a positive blood culture for CMV and 88% had a positive urine culture for CMV. A positive blood culture for CMV was not associated with a fever or weight loss among these patients.