Decreased Survival among AIDS Patients in the United States who Screened Positive for Cryptococcal Infection
Background: Cryptococcus meningitis (CM) is the most common cause of AIDS-related mortality in the world. In sub-Saharan Africa the WHO recommends routine cryptococcal antigen (CrAg) screening in AIDS patients with a CD4 T-cell count ≤ 100 cells/μl and initiating anticryptococcal therapy among positives to prevent CM. In the United States (US) however, there are no recommendations for routine cryptococcal screening. In a cohort study among 1872 AIDS patients in the US, the prevalence of cryptococcal infection was 2.9% overall; in some sub-groups the prevalence was as high as 6.4%. We aimed to determine if survival among those who screened positive was different from those who screened negative for CrAg.
Methods: Using stored sera from the Multicenter AIDS Cohort Study (MACS) and the Women's Interagency HIV Study (WIHS), we screened 1,872 specimens from donors with CD4 T-cell count < 100/μl using the CrAg Lateral Flow Assay (Immy, Norman, OK). Overall survival and survival between multiple sub-groups were compared using adjustment methods.
Results: The number of CrAg positive within this cohort was 55 (2.9%). Survival analysis results (Figure 1) showed a significantly lower survival in those with a positive CrAg result (median = 1 year, P=0.02) and those with a negative CrAg result (median = 2years, P= 0.02). After controlling for CD4 count, age, and if specimen were collected pre or post ART era, women had a longer survival than men (p-value 0.01), and blacks had a longer survival than both Hispanics and whites (p-value 0.02). The probability of 5 year survival for blacks and Hispanics was 30% compared to 10% for whites. Further, the probability of 5 year survival for women was greater than 30% compared to less than 10% in males.
Conclusion: Presently, there are no recommendations for routine cryptococcal screening in AIDS patients in the U.S. The results from this study coupled with the results from an earlier study assessing the prevalence of cryptococcal infection among AIDS patients in the US, suggest not only that cryptococcal screening in those with CD4 ≤ 100 cells/ ul is well above the published cost-effectiveness threshold of 2.0% but that screening could reduce mortality.
Figure 1. Survival analysis by CrAg test result
R. Detels, None
A. French, None
J. Margolick, None
S. K. Bauman, None
B. Neary, None
B. Doherty, None