Chemoprophylaxis for Pneumocystis Carinii Pneumonia in AIDS

Abstract

To the Editor.— The article by Fischl et al 1 presents impressive results for the use of sulfamethoxazole and trimethoprim for the prophylaxis of Pneumocystis carinii pneumonia in patients with acquired immunodeficiency syndrome (AIDS). In this randomized, controlled trial, the authors do show a high degree of correlation between treatment and the prevention of P carinii pneumonia, as well as increasing survival. The study is consistent both with previous studies that show effective prophylaxis for P carinii pneumonia in immunodeficient patients and with known information on AIDS and P carinii pneumonia. Measurement bias was reduced by providing a methodology for diagnosing Pneumocystis that reduced interobserver error, false-positive error, and false-negative error. However, use of a blinded study would have increased the reliability of the diagnosis of Pneumocystis by reducing intraobserver error and interobserver bias as well as placebo effect. Since the study was not blinded, it is possible that a