Abstract & Commentary
By Nathan I. Shapiro, MD, MPH, Research Director, Harvard Medical School, Beth Israel Deaconess Medical Center, Department of Emergency Medicine, Boston, MA.
Source: Marrie TJ, et al. Factors influencing in-hospital mortality in community-acquired pneumonia. Chest 2005: 127:1260-1270.
Community acquired pneumonia (CAP) remains a serious health care issue with an incidence rate of approximately 11.6/1000 adults per year, of which approximately 30% are admitted to a hospital. The case mortality rate is approximately 10%. There are a number of recommendations as to the best available approach to the care of patients with pneumonia. This investigation is part of a larger study looking at the effect of a pneumonia pathway on patient outcomes.
The specific goals of this study were to determine the factors that predict mortality in patients admitted to the hospital in a non-intensive care unit (ICU) setting with CAP. This is a six-hospital (two tertiary care, two mixed tertiary and community, and two community hospitals) study where an evidenced-based pathway was implemented. Included in the study were adult patients with pneumonia defined by two or more symptoms on history or physical examination plus radiographic evidence of pneumonia. Exclusion criteria were: ICU admission, palliative care, physician unwillingness, pregnancy, immunosuppression, nosocomial pneumonia, underlying lung disease, and a change to a non-pneumonia diagnosis within 48 hours. Patients were placed on a standardized pathway that included criteria for admission, standardized antibiotics, and criteria for eventual discharge from the hospital. Investigators collected elements of history, physical examination, co-morbidities, functional status, administered treatments and laboratory testing. These factors underwent a comprehensive statistical analysis using univariate and multivariate regression along with propensity scoring to determine which were independently associated with death.
During the two-year study period, 3043 patients were included with a total of 246 deaths (8.1%). The population was generally older (mean age 69.6 ± 17.7 years with 68% age > 65), had an average pneumonia risk (Patients Outcome Research Team [PORT]) score of 101.2 (±35), and was male-predominant (52%). The crude mortality rate by functional status evaluated by ambulation status was: walking independently (4.0%), walking with assistance (11.6%), wheelchair bound (20.1%), and bedridden (25.2%).
Using a multivariate regression model, the following variables were all determined to be statistically significant independent predictors of death: pneumonia risk score, age, functional status determined by ability to walk, individual hospital, antibiotic therapy with levofloxacin (i.e., may be a marker of pathway use), and consultation with an infectious disease specialist (i.e., likely marker for complexity). Patients were then stratified by time of death, with five days or fewer considered early and six days or more considered late. Pneumonia risk score, age, and functional status remained significant predictors of death for both early and late mortality, while use of a pathway, lymphocytes < 1000, potassium > 5 mEq/L (correlated with creatinine > 2 mg/dL), and substance abuse were predictive of early mortality only. An infectious disease consultation and treatment with levofloxacin or ceftriaxone/azithromycin were predictive of late mortality.
The authors concluded that functional status at the time of hospital admission is an important predictor of mortality. This is above the effect of age and pneumonia risk score and should be included in any risk assessment of patients with CAP.
Commentary
This is a large-scale, multi-center study that underscores the importance of functional status as a predictor of mortality. This effect is independent of age and risk score, and should be a critical consideration in the ED patient with pneumonia, although it perhaps is not sufficiently accounted for in the current PORT risk score.
This study is part of an industry-sponsored implementation study of a pneumonia pathway where, although benefit from levofloxacin is implied, the study design does not permit proper assessment of this conclusion, and the results could be purely from effects of protocol compliance or the confounding effects of more complicated pneumonias in other therapy groups. Compliance with the pathway showed a strong trend toward beneficial effect for all deaths and had a statistically significant protective effect on early mortality. A regimented pneumonia pathway deserves consideration when organizing an institutional approach to the patient with pneumonia. Patients who did not receive antibiotics were excluded from the study without explanation, and readers are not informed if this occurred in the setting of a pathway.
This complex analysis gives EPs an important take-home message when assessing ED patients with pneumonia. Specifically, risk score, age, and functional status are important prognosticators of mortality, and each should be considered in mortality prediction and when considering discharge disposition.
There are a number of recommendations as to the best available approach to the care of patients with pneumonia. This investigation is part of a larger study looking at the effect of a pneumonia pathway on patient outcomes.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content