Correspondence

Primary Prophylaxis against Pneumocystis carinii Pneumonia

N Engl J Med 1993; 328:1499May 20, 1993

Article

To the Editor:

Schneider et al. (Dec. 24 issue)1 concluded that a single dose (either 480 mg or 960 mg) of trimethoprim-sulfamethoxazole once a day is superior to aerosolized pentamidine once a month for the prevention of Pneumocystis carinii pneumonia (PCP) in patients with human immunodeficiency virus (HIV) infection.

All the patients had comparable base-line CD4 cell counts. The authors do not report CD4 cell counts for the follow-up period. Zidovudine,2-4 which was used by many patients in this study, may increase the CD4 cell count and therefore diminish the risk of PCP. In the three groups of patients, were the CD4 counts of those who had PCP comparable? If not, the differences in the incidence of PCP may not be accounted for by the differences between the prophylactic regimens.

Richard Tarabey, M.D.
Veterans Affairs Medical Center, North Chicago, IL 60064

4 References

1. 1

   Schneider MME, Hoepelman AIM, Eeftinck Schattenkerk JKM, et al. A controlled trial of aerosolized pentamidine or trimethoprim-sulfamethoxazole as primary prophylaxis against Pneumocystis carinii pneumonia in patients with human immunodeficiency virus infection. N Engl J Med 1992;327:1836-1841
   Full Text | Web of Science | Medline

2. 2

   Stein DS, Korvick JA, Vermund SH. CD4+ lymphocyte cell enumeration for prediction of clinical course of human immunodeficiency virus disease: a review. J Infect Dis 1992;165:352-363
   CrossRef | Web of Science | Medline

3. 3

   Cooper DA, Pedersen C, Aiuti F, et al. The efficacy and safety of zidovudine with or without acyclovir in the treatment of patients with AIDS-related complex. AIDS 1991;5:933-943
   CrossRef | Web of Science | Medline

4. 4

   Volberding PA, Lagakos SW, Koch MA, et al. Zidovudine in asymptomatic human immunodeficiency virus infection: a controlled trial in persons with fewer than 500 CD4-positive cells per cubic millimeter. N Engl J Med 1990;322:941-949
   Full Text | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: At the time of entry into the study, the six patients in the pentamidine group in whom PCP developed had a mean CD4 cell count that was not significantly different from that of the other patients in the three treatment groups. Although we did not report CD4 cell counts during the study, there is no reason to assume that these six patients had a faster decline in these counts than the other patients. Furthermore, there is no reason to suggest that the use of zidovudine may have played a more important part in the absence of PCP in the patients receiving trimethoprim-sulfamethoxazole than in the patients receiving pentamidine. On the contrary, 65 percent of the patients in the pentamidine group have used zidovudine, as compared with the 45 percent of the patients in the group given 480 mg of trimethoprim-sulfamethoxazole and the 55 percent of the patients in the group given 960 mg of trimethoprim-sulfamethoxazole. Three of the six patients in whom PCP developed (all in the pentamidine group) used zidovudine. We conclude that the lower incidence of PCP in the trimethoprim-sulfamethoxazole groups is accounted for by the drug itself, not by another factor.

Margriet M.E. Schneider, M.D.
Andy I.M. Hoepelman, M.D., Ph.D.
Jan C.C. Borleffs, M.D., Ph.D.
University Hospital Utrecht, 3584 CX Utrecht, the Netherlands