Also, although we identified residents prospectively, project nurses were unable to evaluate 9.2% of residents before transfer to a hospital. Clinical findings abstracted from medical records, such as lung findings, may not have been complete. It is also possible that project nurses could have missed some important findings. However, our staff provided a higher level of expertise than is typically available in nursing homes. In fact, this may limit application of our findings. Nursing home staff vary widely in their ability to accurately examine residents or even identify illness. In many instances, facility staff had not obtained vital signs at the point when we identified a resident as ill enough to qualify for an evaluation.25 Therefore, in many nursing homes, physicians may lack confidence to apply our rule without an evaluation by a physician, advanced practice nurse, or physician assistant.
Finally, determining whether subjects had pneumonia primarily depended on our classification of radiographic reports. Though radiographs generally included 2 views, many were portable films of variable quality, and frequently there was no previous radiograph for comparison. In some subjects with pneumonia, radiographic infiltrates might not yet have developed. Also, even under ideal conditions, radiologists commonly disagree on the presence of pneumonia.26 Some subjects may have been misclassified. However, unless radiographic technique or interpretation was specifically related to clinical predictors, misclassification would simply diminish the relationship of predictors to pneumonia rather than creating a bias. We reviewed reports rather than radiographs, because that is the information usually available to clinicians faced with diagnosis and treatment decisions. We also paid special attention to avoiding any bias in the interpretations. All data were recorded before interpreting radiology reports and the interpretations were performed independent of clinical data. We also made special efforts to assure consistency in labeling radiology reports as possible, probable, or negative for pneumonia. When lack of agreement persisted, the study radiologist reinterpreted the actual films.
Conclusions
Most nursing home residents with pneumonia have few symptoms. We created a simple scoring to identify nursing home residents who have a high probability of radiographic pneumonia. If our results are confirmed, physicians might consider initiating treatment without an x-ray in such residents. Low scores do not rule out pneumonia, and most physicians would want to press for further diagnosis or treatment in this group.
Acknowledgments
This study was supported by the Agency for Healthcare Research and Quality (grant HS08551) and Dr Mehr’s Robert Wood Johnson Foundation Generalist Physician Faculty Scholars award. Dr Kruse was partially supported by an Institutional National Research Service Award (PE10038) from the Health Resources and Services Administration. Our project would not have been possible without the support of the many attending physicians, administrators, and staff of the involved nursing homes. Dr Clive Levine re-read more than 200 radiographs; Karen Davenport provided crucial administrative support; and Karen Madrone, MPA, assisted with manuscript preparation. Many other unnamed project staff also contributed.