Third, the lack of a unique patient identifier in the database precluded our ability to follow up patients beyond hospital discharge, and to examine hospital readmission and postdischarge mortality. Although such information would allow for a more thorough assessment of the effectiveness of ICU care, routine collection of identifiers, such as the social security number, raises important concerns about patient confidentiality. However, as care is increasingly delivered in settings outside the hospital, the ability to link individual encounters to a single episode of care will become increasingly important to evaluating patient outcomes and health-care quality, particularly in the context of the current analysis in which hospital mortality may no longer be an adequate marker of ICU performance.
Fourth, while our measure of severity of illness exhibited excellent discrimination, it is possible that variations in mortality may be due to prognostic factors, such as functional status, mental health, or social support, that are not assessed by physiologically based methods, such as APACHE III. In addition, health insurance status may contribute to outcomes. Lastly, no information was collected regarding the goals of ICU treatment, patient and/or family preferences for specific ICU treatments, or resuscitation status. As shown previously, the use of do not resuscitate orders and other treatment limitations have increased over time, and may differ across institution. Such practices may confound the interpretation of our data with respect to hospital performance. asthma inhalers
The findings of the current study have important implications for the delivery of critical care and the assessment of health-care quality, but also raise further questions. While some studies have suggested that greater ICU specialization may be associated with better outcomes, current uncertainty about the value of regionalizing high-intensity, critical care services stems, in part, from the lack of valid ICU performance data in most regions.