We were interested in the comments of Khaliq and Lamp regarding our article that appeared in the March 1992 issue of the Archives.1 Their critique emphasizes, as we did, the retrospective nonrandomized nature of our study. However, many of their comments are not relevant to the study that was done. Prospective, randomized studies2,3 of Pneumocystis carinii pneumonia (PCP) prophylaxis have been performed with results that agree with our conclusions.
Our study groups were not mutually exclusive. As stated in the article, a total 211 patients were prescribed one or more of the three prophylactic regimens. Patient experiences while taking each drug were totaled and reported in "patient-months." Consequently, PCP occurrences and recurrences were reported as "episodes per patient-month," not as percentages.
The treatment period for dapsone and aerosolized pentamidine for each patient who developed PCP when receiving these regimens is clearly documented in our article. (Primary-prophylaxis patients took