Stopping Treatment with Antibiotics That Prevent Mycobacterium avium Complex Infection in Persons with HIV Infection Who Have Responded Well to Anti-HIV Drugs FREE

Mycobacterium avium complex (MAC) bacteria can cause illness (fevers, low blood counts, diarrhea, abdominal pain, and weight loss) in persons infected with HIV. The CD4⁺ count is a measure of immune cells; high CD4⁺ cell counts are better than low ones. When HIV infection causes patients' CD4⁺ counts to fall below 50 cells per cubic milliliter of blood (cells/mm³), the risk for infection with MAC bacteria increases greatly; guidelines recommend that at that point patients should take antibiotics that prevent MAC infection. Powerful anti-HIV drugs can allow CD4⁺ cell counts to rise. It is not known, however, whether it is safe to stop treatment with the antibiotics that prevent MAC infection in persons taking anti-HIV drugs once their CD4⁺ cell counts have risen.

To see whether it is safe to stop treatment with antibiotics that prevent MAC infections in persons taking anti-HIV drugs whose CD4⁺ cell counts have risen to over 100 cells/mm³.

The investigators studied 643 persons with HIV infection whose CD4⁺ cell counts had been below 50 cells/mm³ but then rose above 100 cells/mm³ while they were taking anti-HIV treatment.

The researchers randomly assigned study patients to continue their anti-MAC antibiotics or to take a placebo that looked like the antibiotic but contained no active ingredient. They then followed the patients to see who developed MAC infections; one method they used was testing blood samples for MAC every 8 weeks.

During an average of 16 months, 2 cases of MAC infection occurred among the 321 study patients taking placebo. No MAC infections occurred among the 322 study patients who continued taking anti-MAC antibiotics. However, statistical tests showed that these results could have happened by chance, suggesting that it is safe to stop treatment with antibiotics to prevent MAC infection in persons taking anti-HIV treatment whose CD4⁺ counts rise above 100 cells/mm³.

Because so few MAC infections occurred, this study cannot exclude the possibility that more MAC infections could really occur without anti-MAC antibiotics than with them. In addition, while the study required that participants have CD4⁺ cell counts above 100 cells/mm³, the average CD4⁺ cell count was actually 230 cells/mm³. These results may not apply to patients with smaller improvements in CD4⁺ cell counts.

Stopping treatment with antibiotics that prevent MAC infection in persons with HIV infection who are taking anti-HIV drugs and whose CD4⁺ cell counts rise above 100 cells/mm³ does not appear to cause a significant increase in MAC infections.

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician.

The summary below is from the full report titled “Discontinuation of Mycobacterium avium Complex Prophylaxis in Patients with Antiretroviral Therapy–Induced Increases in CD4⁺ Cell Count. A Randomized, Double-Blind, Placebo-Controlled Trial.” It is in the 3 October 2000 issue of Annals of Internal Medicine (volume 133, pages 493-503). The authors are JS Currier, PL Williams, SL Koletar, SE Cohn, RL Murphy,AE Heald, R Hafner, EL Bassily, HM Lederman, C Knirsch, CA Benson, H Valdez, JA Aberg, and JA McCutchan .