OBJECTIVE: Subtle presentation and the frequent lack of on-site physicians complicate the diagnosis of pneumonia in nursing home residents. We sought to identify clinical findings (signs, symptoms, and simple laboratory studies) associated with radiographic pneumonia in sick nursing home residents.
STUDY DESIGN: This was a prospective cohort study.
POPULATION: The residents of 36 nursing homes in central Missouri and the St. Louis area with signs or symptoms suggesting a lower respiratory infection were included.
OUTCOME MEASURED: We compared evaluation findings by project nurses with findings reported from chest radiographs.
RESULTS: Among 2334 episodes of illness in 1474 nursing home residents, 45% of the radiograph reports suggested pneumonia (possible=12%; probable or definite = 33%). In 80% of pneumonia episodes, subjects had 3 or fewer respiratory or general symptoms. Eight variables were significant independent predictors of pneumonia (increased pulse, respiratory rate Ž30, temperature Ž38°C, somnolence or decreased alertness, presence of acute confusion, lung crackles on auscultation, absence of wheezes, and increased white blood count). A simple score (range = -1 to 8) on the basis of these variables identified 33% of subjects (score Ž3) with more than 50% probability of pneumonia and an additional 24% (score of 2) with 44% probability of pneumonia.
CONCLUSIONS: Pneumonia in nursing home residents is usually associated with few symptoms. Nonetheless, a simple clinical prediction rule can identify residents at very high risk for pneumonia. If validated in other studies, physicians could consider treating such residents without obtaining a chest radiograph.
Pneumonia is a leading cause of morbidity, mortality, and hospitalization of nursing home residents.1-8 Atypical presentations and fewer presenting signs and symptoms in older patients complicate diagnosis.9,10 Also, clinician (physician, nurse practitioner, and physician assistant) visits to nursing homes are often sporadic, and radiology facilities are rarely on the premises. As a consequence, residents are commonly sent to emergency departments for evaluation,4,11,12 which undoubtedly contributes to a high hospitalization rate.
Clinicians who periodically see nursing home residents could benefit from a simple clinical tool to identify pneumonia. No large studies of community nursing home residents have systematically studied findings associated with pneumonia. As part of the Missouri LRI Project, we examined how well clinical findings predict radiographic pneumonia.
Methods
The Missouri LRI Project was a prospective observational study in 36 nursing homes in Central Missouri and St. Louis designed to investigate predictors of 2 outcomes of lower respiratory infections (LRIs): mortality and functional decline. Potential cases were identified from August 15, 1995, through September 29, 1998; however, all facilities were not involved until fall 1997. Study facilities were similar in size, ownership, and occupancy to national estimates from the 1995 National Nursing Home Survey (data available on request).13
We trained nursing home staff to report ill residents with any of 6 respiratory symptoms (eg, cough, dyspnea, sputum production) or 6 general symptoms (eg, fever, decline in mobility, mental status changes). Project nurses called and visited facilities frequently to reinforce reporting. Under a physician-authorized protocol, ill residents with a possible LRI received a standardized evaluation by a trained project nurse and usually a chest radiograph, complete blood count, and a chemistry panel. Complete criteria for triggering an evaluation are listed in Table 1. For this paper, we were concerned with the 90% of evaluated residents who received a chest radiograph. Criteria for excluding residents from evaluation are summarized in the Figure 1.
The nurse evaluation included an inventory of current symptoms, a review of important chronic conditions (eg, congestive heart failure), and a targeted physical examination. The examination included vital signs and the following body areas or systems: ears, nose, and throat; cardiac; abdominal; neurologic; extremities; skin; and a detailed lung examination. Most project nurses had advanced practice training; the remainder had extensive clinical experience and training in physical assessment. All received an individualized training session with a project geriatrician. Project nurses had substantially more experience than the nursing home staff, who usually report clinical findings to physicians.
Results of the evaluation were reported to the attending physician, who made all treatment decisions. Since the evaluations were clinically appropriate care authorized by individual attending physicians, the institutional review boards that reviewed the project allowed us to substantially simplify the consent process to a simple acceptance or refusal of the evaluation. In 9.2% of evaluations the resident was transferred to the hospital before project nurses could complete a physical assessment. In these instances, we obtained vital sign and clinical examination data from hospital records.
Radiographic Classification
Since all subjects had at least one illness symptom, for this analysis we classified the presence or absence of pneumonia on the basis of reported radiographic findings. Using defined criteria, 2 clinicians independently separated radiology reports into 3 categories: (a) negative, (b) possible, or (c) probable or definite for pneumonia (hereafter, probable pneumonia). For example, a report describing “new left lower lobe infiltrate suggestive of pneumonia” would have been rated as probable, while a report indicating “possible infiltrate” or “infiltrate suggestive of pneumonia or congestive heart failure” would have been rated as possible. As radiologists rarely provide completely unequivocal readings, we did not separate probable and definite pneumonia. In St. Louis 2 clinicians evaluated the reports, and in central Missouri 2 of 4 clinicians considered each report. Where there was disagreement, all 6 raters from the 2 sites independently reviewed the reports and then attempted to reach consensus. For 13% of radiographs, the project radiologist independently interpreted the actual films. This occurred when: (1) consensus could not be achieved; or (2) consensus was possible pneumonia, but probable pneumonia was needed to quality the episode as an LRI under the project definition.