Background: Thrombocytopenia is a common condition among HIV-infected individuals, however its significance is unclear, particularly among women. Two previous studies, one consisting mostly of men (

Sullivan PS, et al. J Acquir Immune Defic Syndr. 1997;14:374–379
) and one of hemophiliacs (
Ehmann WC, et al. Am J Hematol. 1997; 54:296–300
), have suggested that low platelet count is associated with decreased survival.

Methods: The Women’s Interagency HIV Study (WIHS) is a long-term prospective cohort study of HIV-infected women and HIV-negative women that is being conducted at six urban sites across the United States. 1,990 HIV-infected women and 553 HIV-negative women are included in this report. These women are seen every six months; the median follow-up time is 7.5 years. We conducted extensive multivariate analysis using both generalized estimating equations and Cox proportional hazards models in order to determine the predictors of thrombocytopenia and the role of platelet count in mortality among women being followed as part of this study.

Results: At baseline, 15% of HIV-positive women were thrombocytopenic versus 1.6% of HIV-negative women (p<0.001). Factors associated with increased risk of thrombocytopenia included HIV infection, low CD4 cells, increasing viral load, and smoking. African-American women were significantly protected against thrombocytopenia when compared to Whites, as reported by others (

Sloand EM, et al. Eur J Haematol. 1992; 48:168–72
; Sullivan PS, et al. J Acquir Immune Defic Syndr. 1997;14:374–379
). Resolution of thrombocytopenia was associated with highly-active antiretroviral therapy (p<0.001), especially that containing zidovudine (<0.0001). On multivariate analysis, thrombocytopenia was a significant predictor of mortality, with women having a platelet count <50,000 cells/mm3 being at more than 5-fold increased risk of dying due to any cause, and at 3-fold increased risk of death due to AIDS compared to women with a platelet count in the normal range. Only CD4+ lymphocyte count <200 cells/mm3 was similar in the magnitude of its effect on mortality. The reasons for decreased survival associated with low platelet count in the context of HIV-infection are unclear and further study is needed.

Conclusions: (1) Thrombocytopenia is associated with HIV infection (p<0.001), and with parameters of more advanced HIV disease in women; (2) African American HIV + women are protected from thrombocytopenia compared to HIV + white women (p<0.0001); (3) HAART is associated with resolution of thrombocytopenia, especially those regimens including AZT (p<0.001); (4) Thrombocytopenia is an independent risk factor for decreased survival in HIV infected women.

Topics:
acquired immunodeficiency syndrome, hiv, thrombocytopenia, hiv infections, zidovudine, anti-retroviral agents, antiretroviral therapy, highly active, follow-up, hiv seropositivity, viral load result

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2005, The American Society of Hematology
2004
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