To the Editor.
—I congratulate Dr Rangel-Frausto and colleagues1 on their recent study that describes the course and natural history of the systemic inflammatory response syndrome (SIRS). The authors provide us with an extensive patient population that was prospectively followed for the duration of their hospital stay, and they provide insight into the development of adverse sequelae and other significant events along the continuum of SIRS.However, I would like to comment on two potential areas of confusion related to this study. First, the authors imply that SIRS can develop into sepsis as part of the natural progression of SIRS. In actuality, according to the proposed terminology of the American College of Chest Physicians—Society of Critical Care Medicine Consensus Conference on sepsis,2 SIRS encompasses sepsis when its response is secondary to a documented infection. Therefore, sepsis is a form of SIRS and not an initial stage of SIRS