Investigation of the ability of the Pneumonia Severity Index to accurately predict clinically relevant outcomes: a European study

In order to confirm the validity of the Pneumonia Severity Index (PSI) for patients in Europe, data from adults with pneumonia who were enrolled in two prospective multicentre studies, conducted in France (Pneumocom-1, n = 925) and Spain (Pneumocom-2, n = 853), were compared with data from the original North American study (Pneumonia PORT, n = 2287). The primary outcome was 28-day mortality; secondary outcomes were subsequent hospitalisation for outpatients, and intensive care unit admission and length of stay for inpatients. All outcomes within individual risk classes, and mortality rates in low-risk (PSI I-III) and higher-risk patients, were compared across the three cohorts. Overall mortality rates were 4.7% in Pneumonia PORT, 6.3% in Pneumocom-2 and 10.6% in Pneumocom-1 (p <0.01), ranging from 0.4% to 1.6% (p 0.06) for low-risk patients and from 13.0% to 19.1% (p 0.24) for high-risk patients. Despite significant differences in baseline patient characteristics, none of the study outcomes differed within the low-risk classes. The sensitivity and negative predictive value of low-risk classification for mortality exceeded 93% and 98%, respectively. Thus, in two independent European cohorts, the PSI predicted patient outcomes accurately and reliably, particularly for low-risk patients. These findings confirm the validity of the PSI when applied to patients from Europe.

Validation of a clinical prognostic model to identify low-risk patients with pulmonary embolism

OBJECTIVE

To validate the Pulmonary Embolism Severity Index (PESI), a clinical prognostic model which identifies low-risk patients with pulmonary embolism (PE).

DESIGN

Validation study using prospectively collected data.

SETTING

A total of 119 European hospitals.

SUBJECTS

A total of 899 patients diagnosed with PE.

INTERVENTION

The PESI uses 11 clinical factors to stratify patients with PE into five classes (I-V) of increasing risk of mortality. We calculated the PESI risk class for each patient and the proportion of patients classified as low-risk (classes I and II). The outcomes were overall and PE-specific mortality for low-risk patients at 3 months after presentation. We calculated the sensitivity, specificity and predictive values to predict overall and PE-specific mortality and the discriminatory power using the area under the receiver operating characteristic curve.

RESULTS

Overall and PE-specific mortality was 6.5% (58/899) and 2.3% (21/899) respectively. Forty-seven per cent of patients (426/899) were classified as low-risk. Low-risk patients had an overall mortality of only 1.2% (5/426) and a PE-specific mortality of 0.7% (3/426). The sensitivity was 91 [95% confidence interval (CI): 81-97%] and the negative predictive value was 99% (95% CI: 97-100%) for overall mortality. The sensitivity was 86% (95% CI: 64-97%) and the negative predictive value was 99% (95% CI: 98-100%) for PE-specific mortality. The areas under the receiver operating characteristic curve for overall and PE-specific mortality were 0.80 (95% CI: 0.75-0.86) and 0.77 (95% CI: 0.68-0.86) respectively.

CONCLUSIONS

This validation study confirms that the PESI reliably identifies low-risk patients with PE who are potential candidates for less costly outpatient treatment.

Solutions for difficult diagnostic cases of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common illness that creates significant burdens upon the healthcare system. Improving the quality of medical care for patients with this illness requires an evidence-based and cost-efficient treatment approach. The first step in this approach is to make an accurate diagnosis, while considering the full differential diagnosis of the illness. This requires an understanding of the sensitivity and specificity of the history and physical examination to establish the diagnosis of CAP. The second step is to quantify severity of illness, which can help physicians determine the appropriate initial site of treatment, intensity of the diagnostic evaluation, and choice of initial antibiotic therapy. Case histories are presented to outline the clinical application of an approach that uses the Pneumonia Patient Outcomes Research Team (PORT) prediction rule for prognosis to quantify the severity of illness, and recent guidelines for the management of CAP are highlighted.

What factors influence physicians' decisions to switch from intravenous to oral antibiotics for community-acquired pneumonia?

OBJECTIVE

One of the major factors influencing length of stay for patients with community-acquired pneumonia is the timing of conversion from intravenous to oral antibiotics. We measured physician attitudes and beliefs about the antibiotic switch decision and assessed physician characteristics associated with practice beliefs.

DESIGN

Written survey assessing attitudes about the antibiotic conversion decision.

SETTING

Seven teaching and non-teaching hospitals in Pittsburgh, Pa.

PARTICIPANTS

Three hundred forty-five generalist and specialist attending physicians who manage pneumonia in 7 hospitals.

MEASUREMENTS AND RESULTS

Factors rated as "very important" to the antibiotic conversion decision were: absence of suppurative infection (93%), ability to maintain oral intake (79%), respiratory rate at baseline (64%), no positive blood cultures (63%), normal temperature (62%), oxygenation at baseline (55%), and mental status at baseline (50%). The median thresholds at which physicians believed a typical patient could be converted to oral therapy were: temperature < or =100 degrees F (37.8 degrees C), respiratory rate < or =20 breaths/minute, heart rate < or =100 beats/minute, systolic blood pressure > or =100 mm Hg, and room air oxygen saturation > or =90%. Fifty-eight percent of physicians felt that "patients should be afebrile for 24 hours before conversion to oral antibiotics," and 19% said, "patients should receive a standard duration of intravenous antibiotics." In univariate analyses, pulmonary and infectious diseases physicians were the most predisposed towards early conversion to oral antibiotics, and other medical specialists were the least predisposed, with generalists being intermediate (P <.019). In multivariate analyses, practice beliefs were associated with age, inpatient care activities, attitudes about guidelines, and agreeableness on a personality inventory scale.

CONCLUSIONS

Physicians believed that patients could be switched to oral antibiotics once vital signs and mental status had stabilized and oral intake was possible. However, there was considerable variation in several antibiotic practice beliefs. Guidelines and pathways to streamline antibiotic therapy should include educational strategies to address some of these differences in attitudes.

Arterial blood gas and pulse oximetry in initial management of patients with community-acquired pneumonia

OBJECTIVE

To identify the factors associated with the use of arterial blood gas (ABG) and pulse oximetry (PO) in the initial management of patients with community-acquired pneumonia (CAP) and arterial hypoxemia at presentation.

PARTICIPANTS

A total of 944 outpatients and 1,332 inpatients with clinical and radiographic evidence of CAP prospectively enrolled from 5 study sites in the United States and Canada.

ANALYSES

Separate multivariate logistic regression analyses were used to 1) compare measurement of ABG and PO within 48 hours of presentation across sites while controlling for patient differences, and 2) identify factors associated with arterial hypoxemia (PaO2 <60 mm Hg or SaO2 <90% for non-African Americans and <92% for African Americans) while breathing room air.

RESULTS

Range of ABG use by site was from 0% to 6.4% (P =.06) for outpatients and from 49.2% to 77.3% for inpatients (P <.001), while PO use ranged from 9.4% to 57.8% for outpatients (P <.001) and from 47.9% to 85.1% for inpatients (P <.001). Differences among sites remained after controlling for patient demographic characteristics, comorbidity, and illness severity. In patients with 1 or more measurements of oxygenation at presentation, hypoxemia was independently associated with 6 risk factors: age >30 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.7 to 5.9), chronic obstructive pulmonary disease (OR, 1.9; 95% CI, 1.4 to 2.6), congestive heart failure (OR, 1.5; 95% CI, 1.0 to 2.1), respiratory rate >24 per minute (OR, 2.3; 95% CI, 1.8 to 3.0), altered mental status (OR, 1.6; 95% CI, 1.1 to 2.3), and chest radiographic infiltrate involving >1 lobe (OR, 2.2; 95% CI, 1.7 to 2.9). The prevalence of hypoxemia among those tested ranged from 13% for inpatients with no risk factors to 54.6% for inpatients with > or =3 risk factors. Of the 210 outpatients who had > or =2 of these risk factors, only 64 (30.5%) had either an ABG or PO performed. In the 48 outpatients tested without supplemental O2 with > or =2 risk factors 8.3% were hypoxemic.

CONCLUSIONS

In the initial management of CAP, use of ABG and PO varied widely across sites. Increasing the assessment of arterial oxygenation among patients with CAP is likely to increase the detection of arterial hypoxemia, particularly among outpatients.

Temporal trends in outcomes of older patients with pneumonia

BACKGROUND

It is unclear how outcomes of care for patients hospitalized for pneumonia have changed as patterns of health care delivery have changed during the 1990s. This study was performed to determine trends in outcomes of care for older patients hospitalized for pneumonia.

METHODS

This retrospective analysis was based on Medicare claims and included most patients with pneumonia who were older than 65 years and admitted to acute care hospitals in Connecticut between October 1, 1991, and September 30, 1997 (fiscal years 1992-1997). We assessed the trends in hospital costs, discharge destination, hospital mortality rates, mortality rates within 30 days of discharge, and 30-day readmission rates for pneumonia. Multivariate logistic regression analyses were used to adjust for differences in patient characteristics.

RESULTS

The mean (+/- SD) length of stay declined from 11.9 + 11.4 days to 7.7 + 7.2 days between 1992 and 1997. During this period, adjusted in-hospital mortality rates declined (P =.02), while the adjusted risk of discharge to a nursing facility increased (P<.001) and the adjusted risk of hospital readmission for pneumonia within 30 days of discharge increased (P =.05). The adjusted risk of death 30 days after discharge increased, although the difference was not statistically significant (P =.09).

CONCLUSIONS

Between 1992 and 1997, the adjusted risks of mortality after discharge, placement in a nursing facility, and hospital readmission for pneumonia increased among older patients hospitalized for pneumonia, in association with a decline in mean hospital length of stay. These findings raise the question of whether the declining hospital length of stay has negatively affected patient outcomes. Arch Intern Med. 2000;160:3385-3391.

Risk stratification for patients with community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common medical illness with a prognosis that ranges from rapid complete recovery to severe medical complications and death. Approximately 4 million adults are diagnosed with CAP in the US each year; with more than 600,000 (15%) hospitalised. An estimated $4 billion is expended annually on patients with CAP, with inpatient therapy costing as much as 20 times that of outpatient antimicrobial therapy. Determining severity of illness and using this information to risk-stratify patients with CAP is important from several perspectives. Clinically, understanding prognosis can assist physicians in the initial site of treatment decision (home versus hospital) and can be used to communicate expected outcomes to patients. From a research perspective, risk stratification can be used to select appropriate patient subgroups for clinical trials and to provide severity-adjusted outcomes comparisons. From a policy perspective, severity-adjusted outcomes can be used as a proxy for quality of medical care.

Relation between length of hospital stay and costs of care for patients with community-acquired pneumonia

PURPOSE

Patients with pneumonia often remain hospitalized after becoming clinically stable, without demonstrated benefits on outcome. The purposes of this study were to assess the relation between length of hospital stay and daily medical care costs and to estimate the potential cost savings associated with a reduced length of stay for patients with pneumonia.

SUBJECTS AND METHODS

As part of a prospective study of adults hospitalized with community-acquired pneumonia at a community hospital and two university teaching hospitals, daily medical care costs were estimated by multiplying individual charges by department-specific cost-to-charge ratios obtained from each hospital's Medicare cost reports.

RESULTS

The median total cost of hospitalization for all 982 inpatients was $5, 942, with a median daily cost of $836, including $491 (59%) for room and $345 (41%) for non-room costs. Average daily non-room costs were 282% greater on the first hospital day, 59% greater on the second day, and 19% greater on the third day than the average daily cost throughout the hospitalization (all P <0.05), and were 14% to 72% lower on the last 3 days of hospitalization. Average daily room costs remained relatively constant throughout the hospital stay, with the exception of the day of discharge. A projected mean savings of $680 was associated with a 1-day reduction in length of stay.

CONCLUSIONS

Despite institutional differences in total costs, patterns of daily resource use throughout hospitalization were similar at all institutions. A 1-day reduction in length of stay might yield substantial cost-savings.

Clinical presentation, processes and outcomes of care for patients with pneumococcal pneumonia

OBJECTIVE

To describe the presentation, resolution of symptoms, processes of care, and outcomes of pneumococcal pneumonia, and to compare features of the bacteremic and nonbacteremic forms of this illness.

DESIGN

A prospective cohort study.

SETTING

Five medical institutions in 3 geographic locations.

PARTICIPANTS

Inpatients and outpatients with community-acquired pneumonia (CAP).

MEASUREMENTS

Sociodemographic characteristics, respiratory and nonrespiratory symptoms, and physical examination findings were obtained from interviews or chart review. Severity of illness was assessed using a validated prediction rule for short-term mortality in CAP. Pneumococcal pneumonia was categorized as bacteremic; nonbacteremic, pure etiology; or nonbacteremic, mixed etiology.

MAIN RESULTS

One hundred fifty-eight (6.9%) of 2,287 patients (944 outpatients, 1,343 inpatients) with CAP had pneumococcal pneumonia. Sixty-five (41%) of the 158 with pneumococcal pneumonia were bacteremic; 74 (47%) were nonbacteremic with S. pneumoniae as sole pathogen; and 19 (12%) were nonbacteremic with S. pneumoniae as one of multiple pathogens. The pneumococcal bacteremia rate for outpatients was 2.6% and for inpatients it was 6.6%. Cough, dyspnea, and pleuritic pain were common respiratory symptoms. Hemoptysis occurred in 16% to 22% of the patients. A large number of nonrespiratory symptoms were noted. Bacteremic patients were less likely than nonbacteremic patients to have sputum production and myalgias (60% vs 82% and 33% vs 57%, respectively; P <.01 for both), more likely to have elevated blood urea nitrogen and serum creatinine levels, and more likely to receive penicillin therapy. Half of bacteremic patients were in the low risk category for short-term mortality (groups I to III), similar to the nonbacteremic patients. None of the 32 bacteremic patients in risk groups I to III died, while 7 of 23 (30%) in risk group V died. Intensive care unit admissions and pneumonia-related mortality were similar between bacteremic and nonbacteremic groups, although 46% of the bacteremic group had respiratory failure compared with 32% and 37% for the other groups. The nonbacteremic pure etiology patients returned to household activities faster than bacteremic patients. Symptoms frequently persisted at 30 days: cough (50%); dyspnea (53%); sputum production (48%); pleuritic pain (13%); and fatigue (63%).

CONCLUSIONS

There were few differences in the presentation of bacteremic and nonbacteremic pneumococcal pneumonia. About half of bacteremic pneumococcal pneumonia patients were at low risk for mortality. Symptom resolution frequently was slow.

Changing physician prescribing behavior: the community-acquired pneumonia intervention trial

The Notes section welcomes the following types of contributions: (1) practical innovations or solutions to everyday practice problems, (2) substantial updates or elaborations on work previously published by the same authors, (3) important confirmations of research findings previously published by others, and (4) short research reports, including practice surveys, of modest scope or interest. Notes should be submitted with AJHP's manuscript checklist. The text should be concise, and the number of references, tables, and figures should be limited.

Impact of penicillin susceptibility on medical outcomes for adult patients with bacteremic pneumococcal pneumonia

The impact of penicillin susceptibility on medical outcomes for adult patients with bacteremic pneumococcal pneumonia was evaluated in a retrospective cohort study conducted during population-based surveillance for invasive pneumococcal disease in the greater Atlanta region during 1994. Of the 192 study patients, 44 (23%) were infected with pneumococcal strains that demonstrated some degree of penicillin nonsusceptibility. Compared with patients infected with penicillin-susceptible pneumococcal strains, patients whose isolates were nonsusceptible had a significantly greater risk of in-hospital death due to pneumonia (relative risk [RR], 2.1; 95% confidence interval [CI], 1-4.3) and suppurative complications of infection (RR, 4.5; 95% CI, 1-19.3), although only risk of suppurative complications remained statistically significant after adjustment for baseline differences in severity of illness. Among adults with bacteremic pneumococcal pneumonia, infection with penicillin-nonsusceptible pneumococci is associated with an increased risk of adverse outcome.

Associations between initial antimicrobial therapy and medical outcomes for hospitalized elderly patients with pneumonia

BACKGROUND

Although medical practice guidelines exist, there have been no large-scale studies assessing the relationship between initial antimicrobial therapy and medical outcomes for patients hospitalized with pneumonia.

OBJECTIVE

To determine the associations between initial antimicrobial therapy and 30-day mortality for these patients.

METHODS

Hospital records for 12945 Medicare inpatients (> or = 65 years of age) with pneumonia were reviewed. Associations between initial antimicrobial regimens and 30-day mortality were assessed with Cox proportional hazards models, adjusting for baseline differences in patient characteristics, illness severity, and processes of care. Comparisons were made with patients treated with a non-pseudomonal third-generation cephalosporin alone (the reference group).

RESULTS

Initial treatment with a second-generation cephalosporin plus macrolide (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.52-0.96), a non-pseudomonal third-generation cephalosporin plus macrolide (HR, 0.74; 95% CI, 0.60-0.92), or a fluoroquinolone alone (HR, 0.64; 95% CI, 0.43-0.94) was independently associated with lower 30-day mortality. Adjusted mortality among patients initially treated with these 3 regimens became significantly lower than that in the reference group beginning 2, 3, and 7 days, respectively, after hospital admission. Use of a beta-lactam/beta-lactamase inhibitor plus macrolide (HR, 1.77; 95% CI, 1.28-2.46) and an aminoglycoside plus another agent (HR, 1.21; 95% CI, 1.02-1.43) were associated with an increased 30-day mortality.

CONCLUSIONS

In this study of primarily community-dwelling elderly patients hospitalized with pneumonia, 3 initial empiric antimicrobial regimens were independently associated with a lower 30-day mortality. The more widespread use of these antimicrobial regimens is likely to improve the medical outcomes for elderly patients with pneumonia.

Preferences for sites of care among urban homeless and housed poor adults

OBJECTIVE

To describe sources of health care used by homeless and housed poor adults.

DESIGN

In a cross-sectional survey, face-to-face interviews were conducted to assess source of usual care, preferred site of care for specific problems, perceived need for health insurance at different sites of care, and satisfaction with care received. Polychotomous logistic regression analysis was used to identify the factors associated with selecting non-ambulatory-care sites for usual care.

SETTING

Twenty-four community-based sites (i.e., soup kitchens, drop-in centers, and emergency shelters) frequented by the homeless and housed poor in Allegheny County, Pa.

PARTICIPANTS

Of the 388 survey respondents, 85.6% were male, 78.1% African American, 76.9% between 30 and 49 years of age, 59.3% were homeless less than 1 year, and 70.6% had health insurance.

MAIN RESULTS

Overall, 350 (90.2%) of the respondents were able to identify a source of usual medical care. Of those, 51.3% identified traditional ambulatory care sites (i.e., hospital-based clinics, community and VA clinics, and private physicians offices); 28.9% chose emergency departments; 8.0%, clinics based in shelters or drop-in centers; and 2.1%, other sites. Factors associated with identifying nonambulatory sites for usual care included lack of health insurance (relative risk range for all sites [RR] = 3.1-4.0), homelessness for more than 2 years (RR = 1. 4-3.0), receiving no medical care in the previous 6 months (RR = 1. 6-7.5), nonveteran status (RR = 1.0-2.5), being unmarried (RR = 1. 2-3.1), and white race (RR = 1.0-3.3).

CONCLUSIONS

Having no health insurance or need for care in the past 6 months increased the use of a non-ambulatory-care site as a place for usual care. Programs designed to decrease emergency department use may need to be directed at those not currently accessing any care.

Variation in length of hospital stay in patients with community-acquired pneumonia: are shorter stays associated with worse medical outcomes?

PURPOSE

To assess the variation in length of stay for patients hospitalized with community-acquired pneumonia and to determine whether patients who are treated in hospitals with shorter mean stays have worse medical outcomes.

SUBJECTS AND METHODS

We prospectively studied a cohort of 1,188 adult patients with community-acquired pneumonia who had been admitted to one community and three university teaching hospitals. We compared patients' mean length of stay, mortality, hospital readmission, return to usual activities, return to work, and pneumonia-related symptoms among the four study hospitals. All outcomes were adjusted for baseline differences in severity of illness and comorbidity.

RESULTS

Adjusted interhospital differences in mean length of stay ranged from 0.9 to 2.3 days (P <0.001). When the risk of each medical outcome was compared between patients admitted to the hospital with the shortest length of stay and those admitted to longer stay hospitals, there were no differences in mortality [relative risk (RR) = 0.7; 95% CI, 0.3 to 1.7], hospital readmission (RR = 0.8; 95% CI, 0.5 to 1.2), return to usual activities (RR = 1.1; 95% CI, 0.9 to 1.3), or return to work (RR = 1.2; 95% CI, 0.8 to 2.0) during the first 14 days after discharge, or in the mean number of pneumonia-related symptoms 30 days after admission (P = 0.54).

CONCLUSIONS

We observed substantial interhospital variation in the lengths of stay for patients hospitalized with community-acquired pneumonia. The finding that medical outcomes were similar in patients admitted to the hospital with the shortest length of stay and those admitted to hospitals with longer mean lengths of stay suggests that hospitals with longer stays may be able to reduce the mean duration of hospitalization for this disease without adversely affecting patient outcomes.

Processes and outcomes of care for patients with community-acquired pneumonia: results from the Pneumonia Patient Outcomes Research Team (PORT) cohort study

BACKGROUND

Although understanding the processes of care and medical outcomes for patients with community-acquired pneumonia is instrumental to improving the quality and cost-effectiveness of care for this illness, limited information is available on how physicians manage patients with this illness or on medical outcomes other than short-term mortality.

OBJECTIVES

To describe the processes of care and to assess a broad range of medical outcomes for ambulatory and hospitalized patients with community-acquired pneumonia.

METHODS

This prospective, observational study was conducted at 4 hospitals and 1 health maintenance organization in Pittsburgh, Pa, Boston, Mass, and Halifax, Nova Scotia. Data were collected via patient interviews and reviews of medical records for 944 outpatients and 1343 inpatients with clinical and radiographic evidence of community-acquired pneumonia. Processes of care and medical outcomes were assessed 30 days after presentation.

RESULTS

Only 29.7% of outpatients had 1 or more microbiologic tests performed, and only 5.7% had an assigned microbiologic cause. Although 95.7% of inpatients had 1 or more microbiologic tests performed, a cause was established in only 29.6%. Six outpatients (0.6%) died, and 3 of these deaths were pneumonia related. Of surviving outpatients, 8.0% had 1 or more medical complications. At 30 days, 88.9% (nonemployed) to 95.6% (employed) of the surviving outpatients had returned to usual activities, yet 76.0% of outpatients had 1 or more persisting pneumonia-related symptoms. Overall, 107 inpatients (8.0%) died, and 81 of these deaths were pneumonia related. Most surviving inpatients (69.0%) had 1 or more medical complications. At 30 days, 57.3% (non-employed) to 82.0% (employed) of surviving inpatients had returned to usual activities, and 86.1% had 1 or more persisting pneumonia-related symptoms.

CONCLUSIONS

In this study, conducted primarily at hospital sites with affiliated medical education training programs, virtually all outpatients and most inpatients had pneumonia of unknown cause. Although outpatients had an excellent prognosis, pneumonia-related symptoms often persisted at 30 days. Inpatients had substantial mortality, morbidity, and pneumonia-related symptoms at 30 days.

Utilization of health care services among subgroups of urban homeless and housed poor

The objective of this study was to describe health services utilization by homeless and housed poor adults stratified by six-month primary sheltering arrangements. The primary method used in this study was a cross-sectional survey of 373 homeless adults. Interviews at twenty-four community-based sites (in Allegheny County, Pennsylvania) assessed demographic and clinical characteristics, reasons for homelessness, functional status and social support networks, and health services utilization during the previous six months. Multivariate logistic regression analysis identified factors independently associated with health services utilization. Subjects were classified as unsheltered, emergency-sheltered, bridge-housed, doubled-up, and housed-poor. The median age of the subjects was 38.4 years; 78.6 percent were African American and 69.9 percent had health insurance. Overall, 62.7 percent reported health services use in the past six months, with significantly more use among emergency-sheltered and bridge-housed subjects than among unsheltered subjects. The study concludes that health services use among the homeless is substantial and is independently associated with sheltering arrangement, comorbid illness, race, health insurance, and social support.

Assessing prognosis and selecting an initial site of care for adults with community-acquired pneumonia

Over the last 20 years, more than 15 medical practice guidelines and clinical prediction rules have emerged to assist physicians in assessing the prognosis of adult patients with community-acquired pneumonia (CAP) and selecting an appropriately matched initial site of care. Most of these guidelines and rules suffer from major methodological flaws. One, the Pneumonia Patient Outcomes Research Team (PORT) clinical prediction rule, has satisfied rigorous methodological standards for the derivation and validation of high-quality prediction rules. This rule was incorporated into the Infectious Disease Society of America medical practice guideline for the management of adults with CAP. Strengths of the rule include its derivation and validation in over 50,000 inpatients and outpatients; stratification of all immunocompetent adult patients into one of five risk strata for short-term mortality and other unambiguous adverse medical outcomes; initial site of care recommendations for all patients, particularly those at low risk; and reliance on predictor variables readily available to clinicians at the time of initial patient presentation. A recent small-scale intervention trial demonstrates that the pneumonia PORT rule can reduce admissions for adult patients with CAP without compromising patient outcomes.

Relationship of provider characteristics to outcomes, process, and costs of care for community-acquired pneumonia

OBJECTIVES

The authors describe the relation of provider characteristics to processes, costs, and outcomes of medical care for elderly patients hospitalized for community-acquired pneumonia.

METHODS

Using Medicare claims data, Medicare beneficiaries discharged from Pennsylvania hospitals during 1990 with community-acquired pneumonia were identified. Claims data were used to ascertain mortality, readmissions, use of procedures and physician consultations, and the costs of care. The relationship of these measures to provider characteristics was analyzed using regression techniques to adjust for patient characteristics, including comorbidity and microbial etiology.

RESULTS

Among 22,294 pneumonia episodes studied, 30-day mortality was 17.0%. After adjusting for patient characteristics, 30-day mortality and readmission rates were unrelated to hospital teaching status or urban location or to physician specialty. Use of procedures and physician consultations was more common and costs were 11% higher among patients discharged from teaching hospitals compared with nonteaching hospitals. Similarly, costs were 15% higher at urban hospitals compared with rural hospitals. General internists and medical subspecialists used more procedures and had higher costs than family practitioners.

CONCLUSIONS

Processes and costs of care for community-acquired pneumonia varied by provider characteristics, but neither mortality nor readmission rates did. These differences cannot be explained by clinical variables in the database. Further studies should determine whether less costly patterns of care for pneumonia, and perhaps other conditions, could replace more costly ones without compromising patient outcomes.

Outpatient management of community-acquired pneumonia

Recently published guidelines permit the decision to treat patients with community-acquired pneumonia on an outpatient basis to be made more confidently than in the past. In most cases, the risk of 30-day mortality can be evaluated without extensive laboratory testing. Antibiotic therapy with erythromycin or doxycycline is generally effective.

Time to clinical stability in patients hospitalized with community-acquired pneumonia: implications for practice guidelines

CONTEXT

Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established.

OBJECTIVE

To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability.

DESIGN

Prospective, multicenter, observational cohort study.

SETTING

Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia.

PATIENTS

Six hundred eighty-six adults hospitalized with community-acquired pneumonia.

MAIN OUTCOME MEASURES

Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit.

RESULTS

The median time to stability was 2 days for heart rate (< or =100 beats/min) and systolic blood pressure (> or =90 mm Hg), and 3 days for respiratory rate (< or =24 breaths/min), oxygen saturation (> or =90%), and temperature (< or =37.2 degrees C [99 degrees F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability.

CONCLUSIONS

Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management.

Patients hospitalized after initial outpatient treatment for community-acquired pneumonia

STUDY OBJECTIVE

To determine the incidence, causes, and outcomes of patients hospitalized within 30 days of initiating outpatient treatment for community-acquired pneumonia (CAP).

DESIGN

Patients were enrolled in the Pneumonia Patient Outcomes Research Team's multicenter, prospective cohort study of CAP. All hospitalizations within 30 days of study enrollment of patients initially treated as outpatients for CAP were recorded. Two physicians used a set of predetermined definitions to independently categorize the reasons for these subsequent hospitalizations. Thirty-day mortality rate and measures of resolution of pneumonia were assessed. The setting included three university teaching hospitals, a community teaching hospital, and a staff model medical practice within a health maintenance organization.

RESULTS

Of the 944 enrollees with CAP initially treated in the outpatient setting, 71 (7.5%) were subsequently hospitalized within 30 days. The reason for subsequent hospitalization was CAP related in 40 patients and comorbidity related in 26 patients; 5 refused an initial offer of hospitalization. Ninety percent of pneumonia-related hospitalizations occurred within 10 days of initial presentation. Patients who were subsequently hospitalized required a median of 14 days to return to usual activities compared with 6 days for those who were not hospitalized (P<.0001). Patients with a subsequent hospitalization had a higher 30-day mortality rate, 4.2% compared with .3% (P<.01).

CONCLUSION

A small proportion of patients with CAP initially treated in the outpatient setting are subsequently hospitalized. Such patients face a higher risk of delayed recovery or death. However, the vast majority of outpatients, whether subsequently hospitalized or not, had a successful resolution of their illness. Subsequent hospitalization by 10 days after initial outpatient treatment seems a reasonable screening tool for potentially unsatisfactory quality of care for patients with CAP.

Community-acquired pneumonia: can it be defined with claims data?

The use of administrative data to study pneumonia is limited because International Classification of Diseases, 9th revision, Clinical Modification (ICD9-CM) diagnosis codes do not specify whether pneumonia is community-acquired (CAP), a key clinical distinction. We classified 212 patients discharged with a diagnosis code for pneumonia as to whether or not they had CAP, using three administrative data-based systems (Diagnosis Related Groups (DRGs) alone, principal diagnosis alone, and a complex algorithm). We examined agreement with classification by clinician chart review. We also compared the length of stay (LOS) and mortality among the CAP populations identified with different methods. Agreement between the clinical review and the three administrative data methods ranged from 86 to 80%. Classification by DRG performed least well. Populations defined by claims data had similar mortality but shorter mean LOS (9.70, 9.40, and 7.91 days for the algorithm, principal diagnosis and DRG methods, respectively) than the clinically defined population (10.85 days). We conclude that studies of CAP using populations identified by claims may underestimate LOS.

Variations in antimicrobial use and cost in more than 2,000 patients with community-acquired pneumonia

PURPOSE

To assess the patterns of antimicrobial use, costs of antimicrobial therapy, and medical outcomes by institution in patients with community-acquired pneumonia.

PATIENTS AND METHODS

The route, dose, and frequency of administration of all antimicrobial agents prescribed within 30 days of presentation were recorded for 927 outpatients and 1328 inpatients enrolled in the Pneumonia Patient Outcomes Research Team (PORT) multicenter, prospective cohort study. Total antimicrobial costs were estimated by summing drug costs, using average wholesale price for oral agents and institutional acquisition prices for parenteral agents, plus the costs associated with preparation and administration of parenteral therapy. Thirty-day outcome measures were mortality, subsequent hospitalization for outpatients, and hospital readmission for inpatients.

RESULTS

Significant variation (P <0.05) in prescribing practices occurred for 17 of the 23 antimicrobial agents used in outpatients across 5 treatment sites, and for 18 of the 20 parenteral agents used in inpatients across 4 treatment sites. The median duration of antimicrobial therapy for treatment site ranged from 11 to 13 days for outpatients (P=0.01), and from 13 to 15 days for inpatients (P=0.49). The overall median cost of antimicrobial therapy was $12.90 for outpatients, and ranged from $10.80 to $58.90 among treatment sites (P <0.0001). The overall median cost of antimicrobial therapy was $228.70 for inpatients, and ranged from $183.70 to $315.60 among sites (P <0.0001). Mortality and hospital readmission for inpatients were not significantly different across sites after adjusting for baseline differences in patient demographic characteristics, comorbidity, and illness severity. Although subsequent hospitalization for outpatients differed by site, the rate was lowest for the site with the lowest antimicrobial costs.

CONCLUSION

Variations in antimicrobial prescribing practices by treatment site exist for outpatients and inpatients with community-acquired pneumonia. Although variation in antimicrobial prescribing practices across institutions results in significant differences in antimicrobial costs, patients treated at institutions with the lowest antimicrobial costs do not demonstrate worse medical outcomes.

Quality of care, process, and outcomes in elderly patients with pneumonia

CONTEXT

Pneumonia is a frequent cause of hospitalization and death among elderly patients, but the relationships between processes of care for pneumonia and outcomes are uncertain, making quality improvement a challenge.

OBJECTIVES

To assess quality of care for Medicare patients hospitalized with pneumonia and to determine whether process of care performance is associated with lower 30-day mortality.

DESIGN

Multicenter retrospective cohort study with medical record review.

SETTING

A total of 3555 acute care hospitals throughout the United States.

PATIENTS

A total of 14069 patients at least 65 years old hospitalized with pneumonia.

MAIN OUTCOME MEASURES

Four processes of care: time from hospital arrival to initial antibiotic administration; blood culture collection before initial hospital antibiotics; blood culture collection within 24 hours of hospital arrival; and oxygenation assessment within 24 hours of hospital arrival. Associations between processes of care and 30-day mortality were determined with logistic regression analysis.

RESULTS

National estimates of process-of-care performance were antibiotic administration within 8 hours of hospital arrival, 75.5% (95% confidence interval [CI], 73.1-77.9); blood cultures before antibiotics, 57.3% (95% CI, 54.5-60.1); initial blood culture collection, 68.7% (95% CI, 66.2-71.2); and initial oxygenation assessment, 89.3% (95% CI, 87.5-90.9). Lower 30-day mortality was associated with antibiotic administration within 8 hours of hospital arrival (odds ratio [OR], 0.85; 95% CI, 0.75-0.96) and blood culture collection within 24 hours of arrival (OR, 0.90; 95% CI, 0.81-1.00). State and territory performance estimates varied from 49.0% to 89.7% for antibiotics given within 8 hours and from 45.6% to 82.6% for blood cultures drawn within 24 hours.

CONCLUSIONS

Administering antibiotics within 8 hours of hospital arrival and collecting blood cultures within 24 hours were associated with improved survival. The fact that states varied widely in the performance of these measures suggests that opportunities exist to improve hospital care of elderly patients with pneumonia.

Influence of age on symptoms at presentation in patients with community-acquired pneumonia

BACKGROUND

Advanced age has become a well-recognized risk factor for death in patients with pneumonia. It may also be associated with reduced symptom reporting, raising the possibility that diagnosis and treatment may be delayed in older patients.

OBJECTIVE

To evaluate the association between age and the presenting symptoms in patients with community-acquired pneumonia.

METHODS

This study was conducted at inpatient and outpatient facilities at 3 university hospitals, 1 community hospital, and 1 staff-model health maintenance organization. Patients included adults (age > or = 18 years) with clinical and radiographic evidence of pneumonia, who were able to complete a baseline interview. The presence of 5 respiratory symptoms and 13 nonrespiratory symptoms were recorded during a baseline patient interview. A summary symptom score was computed as the total number of symptoms at presentation.

RESULTS

The 1812 eligible study patients were categorized into 4 age groups: 18 through 44 years (43%), 45 through 64 years (25%), 65 through 74 years (17%), and 75 years or older (15%). For 17 of the 18 symptoms, there were significant decreases in reported prevalence with increasing age (P < .01). In a linear regression analysis, controlling for patient demographics, comorbidity, and severity of illness at presentation, older age remained associated with lower symptom scores (P < .001).

CONCLUSIONS

Respiratory and nonrespiratory symptoms are less commonly reported by older patients with pneumonia, even after controlling for the increased comorbidity and illness severity in these older patients. Recognition of this phenomenon by clinicians and patients is essential given the increased mortality in elderly patients with pneumonia.

Medical outcomes and antimicrobial costs with the use of the American Thoracic Society guidelines for outpatients with community-acquired pneumonia

CONTEXT

The American Thoracic Society (ATS) published guidelines based on expert opinion and published data--but not clinically derived or validated--for treating adult outpatients with community-acquired pneumonia.

OBJECTIVE

To compare medical outcomes and antimicrobial costs for patients whose antimicrobial therapy was consistent or inconsistent with ATS guidelines.

DESIGN

Multicenter, prospective cohort study.

SETTING

Emergency departments, medical clinics, and practitioner offices affiliated with 3 university hospitals, 1 community teaching hospital, and 1 health maintenance organization.

PARTICIPANTS

A total of 864 immunocompetent, adult outpatients with community-acquired pneumonia: 546 aged 60 years or younger with no comorbidity and 318 older than 60 years or with 1 comorbidity or more.

MAIN OUTCOME MEASURES

Patients' antimicrobial therapy was classified as being consistent or inconsistent with the ATS guidelines. Mortality, subsequent hospitalization, medical complications, symptom resolution, return to work and usual activities, health-related quality of life, and antimicrobial costs were compared among those treated consistently or inconsistently with the guidelines.

RESULTS

Outpatients aged 60 years or younger with no comorbidity who were prescribed therapy consistent with ATS guidelines (ie, erythromycin with some exceptions) had 3-fold lower antimicrobial costs ($5.43 vs $18.51; P<.001) and no significant differences in medical outcomes. Outpatients older than 60 years or with 1 comorbidity or more who were prescribed therapy consistent with ATS guidelines (ie, second-generation cephalosporin, sulfamethoxazole-trimethoprim, or beta-lactam and beta-lactamase inhibitor with or without a macrolide) had 10-fold higher antimicrobial costs ($73.50 vs $7.50; P<.001); despite trends toward higher mortality and subsequent hospitalization, no significant differences in medical outcomes were observed.

CONCLUSION

Our findings support the use of erythromycin as recommended by the ATS guidelines for outpatients aged 60 years or younger with no comorbidity. Although the antimicrobial therapy recommended in outpatients older than 60 years or with 1 comorbidity or more is more costly, this observational study provides no evidence of improved medical outcomes in the small subgroup who received ATS guideline-recommended therapy.

Measuring symptomatic and functional recovery in patients with community-acquired pneumonia

OBJECTIVE

To determine the rates of resolution of symptoms and return to premorbid health status and assess the association of these outcomes with health care utilization in patients with community-acquired pneumonia.

DESIGN

A prospective, multicenter cohort study.

SETTING

Inpatient and outpatient facilities at three university hospitals, one community hospital, and one staff-model health maintenance organization.

PATIENTS

Five hundred seventy-six adults (aged > or = 18 years) with clinical and radiographic evidence of pneumonia, judged by a validated pneumonia severity index to be at low risk of dying.

MEASUREMENTS AND MAIN RESULTS

The presence and severity of five symptoms (cough, fatigue, dyspnea, sputum, and chest pain) were recorded through questionnaires administered at four time points: 0, 7, 30, and 90 days from the time of radiographic diagnosis of pneumonia. A summary symptom score was tabulated as the sum of the five individual severity scores. Patients also provided responses to the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) and reported the number of and reason for outpatient physician visits. Symptoms and health status 30 days before pneumonia onset (prepneumonia) were obtained at the initial interview. All symptoms, except pleuritic chest pain, were still commonly reported at 30 days, and the prevalence of each symptom at 90 days was still nearly twice prepneumonia levels. Physical health measures derived from the SF-36 Form declined significantly at presentation but continued to improve over all three follow-up time periods. Patients with elevated symptom scores at day 7 or day 30 were significantly more likely to report pneumonia-related ambulatory care visits at the subsequent day 30 or day 90 interviews, respectively.

CONCLUSIONS

Disease-specific symptom resolution and recovery of the premorbid physical health status requires more than 30 days for many patients with pneumonia. Delayed resolution of symptoms is associated with increased utilization of outpatient physician visits.

An evaluation of machine-learning methods for predicting pneumonia mortality

This paper describes the application of eight statistical and machine-learning methods to derive computer models for predicting mortality of hospital patients with pneumonia from their findings at initial presentation. The eight models were each constructed based on 9847 patient cases and they were each evaluated on 4352 additional cases. The primary evaluation metric was the error in predicted survival as a function of the fraction of patients predicted to survive. This metric is useful in assessing a model's potential to assist a clinician in deciding whether to treat a given patient in the hospital or at home. We examined the error rates of the models when predicting that a given fraction of patients will survive. We examined survival fractions between 0.1 and 0.6. Over this range, each model's predictive error rate was within 1% of the error rate of every other model. When predicting that approximately 30% of the patients will survive, all the models have an error rate of less than 1.5%. The models are distinguished more by the number of variables and parameters that they contain than by their error rates; these differences suggest which models may be the most amenable to future implementation as paper-based guidelines.

A prediction rule to identify low-risk patients with community-acquired pneumonia

BACKGROUND

There is considerable variability in rates of hospitalization of patients with community-acquired pneumonia, in part because of physicians' uncertainty in assessing the severity of illness at presentation.

METHODS

From our analysis of data on 14,199 adult inpatients with community-acquired pneumonia, we derived a prediction rule that stratifies patients into five classes with respect to the risk of death within 30 days. The rule was validated with 1991 data on 38,039 inpatients and with data on 2287 inpatients and outpatients in the Pneumonia Patient Outcomes Research Team (PORT) cohort study. The prediction rule assigns points based on age and the presence of coexisting disease, abnormal physical findings (such as a respiratory rate of > or = 30 or a temperature of > or = 40 degrees C), and abnormal laboratory findings (such as a pH <7.35, a blood urea nitrogen concentration > or = 30 mg per deciliter [11 mmol per liter] or a sodium concentration <130 mmol per liter) at presentation.

RESULTS

There were no significant differences in mortality in each of the five risk classes among the three cohorts. Mortality ranged from 0.1 to 0.4 percent for class I patients (P=0.22), from 0.6 to 0.7 percent for class II (P=0.67), and from 0.9 to 2.8 percent for class III (P=0.12). Among the 1575 patients in the three lowest risk classes in the Pneumonia PORT cohort, there were only seven deaths, of which only four were pneumonia-related. The risk class was significantly associated with the risk of subsequent hospitalization among those treated as outpatients and with the use of intensive care and the number of days in the hospital among inpatients.

CONCLUSIONS

The prediction rule we describe accurately identifies the patients with community-acquired pneumonia who are at low risk for death and other adverse outcomes. This prediction rule may help physicians make more rational decisions about hospitalization for patients with pneumonia.

The hospital admission decision for patients with community-acquired pneumonia. Results from the pneumonia Patient Outcomes Research Team cohort study

BACKGROUND

The hospital admission decision directly influences the magnitude of resource use in patients with community-acquired pneumonia, yet little information exists on how medical practitioners make this decision.

OBJECTIVES

To determine which factors medical practitioners consider in making the hospital admission decision and which health care services they believe would allow ambulatory treatment of low-risk hospitalized patients with community-acquired pneumonia.

METHODS

Medical practitioners responsible for the hospital admission decision for low-risk patients with community-acquired pneumonia were asked to describe patient characteristics at initial examination that influenced the hospitalization decision, and to identify the health care services that would have allowed initial outpatient treatment of hospitalized patients.

RESULTS

A total of 292 medical practitioners completed questionnaires for 472 (76%) of the 624 low-risk patients eligible for this study. Although all patients had a predicted probability of death of less than 4%, practitioners estimated that 5% of outpatients and 41% of inpatients had an expected 30-day risk of death of more than 5%. Univariate analyses identified 3 practitioner-rated factors that were nearly universally associated with hospitalization: hypoxemia (odds ratio, 173.3; 95% confidence interval, 23.8-1265.0), inability to maintain oral intake (odds ratio, 53.3; 95% confidence interval, 12.8-222.5), and lack of patient home care support (odds ratio, 54.4; 95% confidence interval, 7.3-402.6). In patients without these 3 factors, logistic regression analysis demonstrated that practitioner-estimated risk of death of more than 5% had a strong independent association with hospitalization (odds ratio, 18.4; 95% confidence interval, 6.1-55.7). Practitioners identified home intravenous antibiotic therapy and home nursing observation as services that would have allowed outpatient treatment of more than half (68% and 59%, respectively) of the patients initially hospitalized for treatment.

CONCLUSIONS

Practitioners' survey responses suggest that the availability of outpatient intravenous antimicrobial therapy and home nursing care would allow outpatient care for a large proportion of low-risk patients who are hospitalized for community-acquired pneumonia. These data also suggest that methods to improve practitioners' identification of low-risk patients with community-acquired pneumonia could decrease the hospitalization of such patients. Future studies are required to help physicians identify which low-risk patients could safely be treated in the outpatient setting on the basis of clinical information readily available at presentation.

The hospital discharge decision for patients with community-acquired pneumonia. Results from the Pneumonia Patient Outcomes Research Team cohort study

BACKGROUND

The hospital discharge decision directly influences the length of stay in patients with community-acquired pneumonia, yet no information exists on how physicians make this decision.

OBJECTIVES

To identify the factors physicians considered the factors responsible for extending length of hospital stay in clinically stable patients, and the outpatient medical services that would allow earlier hospital discharge for patients with community-acquired pneumonia.

METHODS

Physicians responsible for the hospital discharge decision of patients with community-acquired pneumonia were asked to identify the factors responsible for extending stay in patients hospitalized beyond stability, and the medical services that could have allowed earlier hospital discharge to occur.

RESULTS

For the 418 eligible patients with community-acquired pneumonia identified during the study, 332 questionnaires (79%) were completed by 168 physicians. Physicians believed 71 patients (22%) were discharged from the hospital 1 day or more (median, 2.5 days) after reaching clinical stability. The most common factors rated as being "very important" in delaying discharge were diagnostic evaluation or treatment of comorbid illness (56%), completion of a "standard course" of antimicrobials (15%), and delays with arrangements for long-term care (14%). Among the 302 patients with available information on both length of hospital stay and stability at discharge, median length of stay was 7.0 days for the 29 low-risk patients hospitalized beyond reaching clinical stability and 5.0 days for the remaining 128 low-risk patients (P < .005); median length of stay was 12.5 days for the 42 medium- and high-risk patients hospitalized beyond reaching clinical stability and 8.0 days in the remaining 113 medium- and high-risk patients (P < .001). Frequently cited medical services that "probably" or "definitely" would have allowed earlier discharge to occur included availability of home intravenous antimicrobial infusion (26%) and home visits by nurses (20%).

CONCLUSIONS

Physicians believed that diagnostic evaluation or treatment of comorbid illness, completion of a standard course of antimicrobial therapy, and delays with arrangements for long-term care delayed hospital discharge in clinically stable patients. Addressing the efficiency of these aspects of inpatient medical care, as well as providing home treatment programs, could decrease the length of hospital stay in patients with community-acquired pneumonia.

Ambulatory patients with community-acquired pneumonia: the frequency of atypical agents and clinical course

OBJECTIVES

To determine the etiology of community-acquired pneumonia in patients treated in an ambulatory setting, using serological methods, and to compare presenting symptoms, radiographic manifestations, and clinical outcomes of patients with pneumonia of "atypical" and undetermined etiology.

PATIENTS AND METHODS

This prospective cohort study was conducted in emergency room and outpatient facilities of Victoria General Hospital, Halifax, Nova Scotia, and in offices of participating family doctors based in Halifax. One hundred forty-nine adults with acute onset of one or more symptoms or signs suggestive of pneumonia and radiographic evidence of pneumonia who provided informed consent were enrolled. Patients known to be HIV positive or who had been discharged from a hospital within the previous 10 days were ineligible for enrollment. Demographic features and clinical data were collected by direct patient interview and chart review by trained research nurses. Outcome measures included quantitative evaluation of pneumonia-specific symptoms, and responses to the Short Form 36 Health Survey at presentation and at 30 days after presentation. Information was also collected on each patient's health prior to pneumonia, as well as the time until each patient's self-reported return to work and to usual activities. The etiology of pneumonia was determined by testing acute and convalescent serum samples for antibodies to Legionella pneumophila serogroup 1, Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, Coxiella burnetii, adenovirus, respiratory syncytia virus, influenza viruses A and B, and parainfluenza viruses 1, 2, 3.

RESULTS

The study population consisted of 149 patients, 54 (36%) of whom were men, with a mean age (+/- SD) of 41 +/- 15 years. An etiological diagnosis was made in 74 (49.7%) patients using serological methods. Etiological agents included M pneumoniae 34 (22.8%); C pneumoniae 16 (10.7%); M pneumoniae and C pneumoniae 5 (3.4%); C burnetii 4 (2.7%); influenza A virus 4 (2.7%); and other agents 6% (7.4%). Three patients (2%) had a conventional bacterial etiology, and 72 patients (48.3%) had pneumonia of undetermined etiology. Patients with pneumonia of known (atypical) and undetermined etiology were similar in terms of age, gender, race, education, employment, and comorbidity. Despite a higher proportion of patients with pneumonia of known etiology reporting sweats, chills, and headache at presentation, the two groups were similar for symptom severity and bother. The patients with pneumonia of undetermined etiology were more likely to have multilobar pneumonia (P < 0.02). Both patients with atypical pneumonia and those with pneumonia of undetermined etiology suffered severe deterioration of physical functioning with a marked but incomplete recovery at 30 days. Those with atypical pneumonia had higher physical functioning and general mental health scores at 30 days.

CONCLUSIONS

Nearly half the cases of ambulatory community-acquired pneumonia are due to "atypical" agents. It is not possible to reliably distinguish patients with atypical pneumonia from those with pneumonia of undetermined etiology by clinical features at baseline. The outcomes in terms of resolution of symptoms, functional status, return to work, and return to usual activities are essentially similar in the two groups.

Do pulmonary radiographic findings at presentation predict mortality in patients with community-acquired pneumonia?

BACKGROUND

Previous studies have reported conflicting results on whether pulmonary radiographic findings predict mortality for patients with community-acquired pneumonia (CAP).

OBJECTIVE

To determine whether pulmonary radiographic findings at presentation are independently associated with 30-day mortality in patients with suspected CAP.

METHODS

This study was conducted as part of the Pneumonia Patient Outcomes Research Team multicenter, prospective cohort study of ambulatory and hospitalized patients with clinical and radiographic evidence of CAP. For each patient with CAP, a structured data form was completed by a panel of radiologists to evaluate the radiographic pattern of infiltrate, number of lobes involved, presence of pleural effusion, and 8 other radiographic characteristics. Cox proportional hazards models were used to evaluate the independent association between radiographic findings and 30-day mortality, while controlling for patient demographic, clinical, and laboratory characteristics with a known association with this outcome.

RESULTS

Of 2287 patients enrolled in the Pneumonia Patient Outcomes Research Team cohort study, 1906 patients (83.3%) had a pulmonary radiographic infiltrate confirmed by the radiology panel. Overall, 30-day mortality in this cohort was 4.9%. Univariate regression analyses demonstrated the following radiographic characteristics to be significantly associated with 30-day mortality: (1) bilateral pleural effusions (risk ratio [RR], 7.0; 95% confidence interval [CI], 3.9-12.6); (2) a pleural effusion of moderate or greater size (RR, 3.4; 95% CI, 1.4-8.4); (3) 2 or more lobes involved with infiltrate (RR, 2.5; 95% CI, 1.6-3.8); (4) bilateral infiltrate (RR, 2.8; 95% CI, 1.9-4.2); (5) bronchopneumonia (RR, 1.6; 95% CI, 1.0-2.7); and (6) air bronchograms (RR, 0.5; 95% CI, 0.2-0.9). Multivariate analysis of radiographic features and other clinical characteristics showed the presence of bilateral pleural effusions (RR, 2.8; 95% CI, 1.4-5.8) was independently associated with mortality.

CONCLUSIONS

In patients with CAP, the presence of bilateral pleural effusions is an independent predictor of short-term mortality. This finding, which is available at presentation, can help guide physicians' assessment of prognosis in CAP.

Interobserver reliability of the chest radiograph in community-acquired pneumonia. PORT Investigators

OBJECTIVE

To evaluate the interobserver reliability of pulmonary radiographic findings in patients with community-acquired pneumonia (CAP).

DESIGN

A prospective, multicenter study.

SETTING

Physician offices, medical walk-in clinics, emergency departments, and inpatient wards affiliated with three university hospitals, one community hospital, and one staff model health maintenance organization in three geographic areas.

METHODS

Copies of the initial chest radiograph of patients suspected of having CAP were independently read by two staff radiologists at the coordinating university hospital. Interobserver reliability for the interpretation for radiographic findings was assessed by calculation of agreement rates and the kappa statistic.

PARTICIPANTS

Adults (age > or = 18 years) with symptoms or signs of CAP and a pulmonary radiographic infiltrate documented by a local study site radiologist.

RESULTS

Among the 282 patients whose initial pulmonary radiographs were evaluated, there was agreement between the two staff radiologists on the presence of infiltrate in 79.4% and on the absence of an infiltrate in 6.0% (kappa = 0.37; 95% confidence interval [CI] = 0.22 to 0.52). For the 224 patients with an infiltrate identified by both radiologists, there was further agreement that the infiltrate was unilobar in 41.5% and multilobar in 33.9% (kappa = 0.51; 95% CI = 0.28 to 0.62), pleural effusion was present in 10.7% and absent in 73.2% (kappa = 0.46; 95% CI = 0.33 to 0.50), and the infiltrate was alveolar in 96.3% of patients and interstitial in no patients (kappa = -0.01; 95% CI = -0.03 to 0.00). Among the 210 patients with an alveolar infiltrate, both radiologists classified the infiltrate as lobar in 74.6% and bronchopneumonia in 2.4% (kappa = 0.09; 95% CI = -0.04 to 0.22), and agreed on the presence of air bronchograms in 7.6% and their absence in 52.9% (kappa = 0.01; 95% CI = -0.13 to 0.15).

CONCLUSION

In patients with CAP, two university radiologists identified the presence of infiltrate, multilobar disease, and pleural effusion with fair to good interobserver reliability. However, interobserver reliability for the pattern of infiltrate and the presence of air bronchograms was poor.

Preferences for home vs hospital care among low-risk patients with community-acquired pneumonia

OBJECTIVE

To measure preferences for initial outpatient vs hospital care among low-risk patients who were being actively treated for community-acquired pneumonia (CAP).

METHODS

Study patients included 159 patients with CAP, 57 (36%) initially hospitalized, who were identified as being at low risk for early mortality using a validated prediction model. Subjects were enrolled from university and community health care facilities located in Boston, Mass, Halifax, Nova Scotia, and Pittsburgh, Pa, participating in the Pneumonia Patient Outcome Research Team prospective cohort study of CAP. Three utility assessment techniques (category scaling, standard gamble, and willingness to pay) were used to measure the strength of patient preferences for the site of care for low-risk CAP. At the time of initial therapy or during the early recuperative period, patient preferences were assessed across a spectrum of potential clinical outcomes using 7 standardized pneumonia clinical vignettes.

RESULTS

Responses to the 7 pneumonia scenarios indicated that most patients consistently preferred outpatient-based therapy. This pattern was observed regardless of whether patients had actually been treated initially at home or in a hospital. Patients (74%) who stated that they generally preferred home care for low-risk CAP were willing to pay a mean of 24% of 1 month's household income to be assured of this preference. Preference for home care, as measured by the category scaling and the willingness to pay, persisted after adjustment for sociodemographic and baseline health status covariates. Sixty nine percent of interviewed patients said that their physician alone determined whether they would be treated in the hospital or at home. Only 11% recalled being asked if they had a preference for either site of care.

CONCLUSIONS

Most patients, even those treated initially in a hospital, who were at low risk for mortality from CAP prefer outpatient treatment. However, most physicians appear not to involve patients in the site-of-care decision. More explicit discussion of patient preferences for the location of care would likely yield more highly valued care by patients as well as less costly treatment for CAP.

Hospitalized pneumonia. Outcomes, treatment patterns, and costs in urban and rural areas

OBJECTIVES

To describe discharge rates, geographic and patient characteristics, treatment patterns, costs, and outcomes of patients hospitalized with community-acquired pneumonia (CAP) in Pennsylvania hospitals and compare these patients from rural and urban counties.

DESIGN

A retrospective database study.

PATIENTS

Adult patients (age > or = 18) with an ICD-9-CM diagnosis of pneumonia discharged from 193 Pennsylvania hospitals (n = 36,222) in 1991 from the MediQual Systems Pennsylvania database.

MEASUREMENTS

Patient characteristics included a pneumonia-specific severity index, microbiologic etiology, and a number of comorbid conditions. Treatment indicators included the specialty of the admitting physician, length of stay, admittance to an intensive care unit, and mechanical ventilation. Cost indicators included charges and estimated costs. Outcomes measured were inpatient mortality and discharge disposition. Counties in Pennsylvania were classified into seven urban or rural groups, and patients were classified by the county of residence.

RESULTS

The discharge rate for CAP was 4.0 per 1,000 and did not vary systematically across urban or rural counties. Most patients were treated in local hospitals. The average distance between residence and hospital was 5.4 miles and varied with urban or rural classification (range 2.5-9.3 miles). Among CAP patients, 37.8% were at low risk of mortality, with no systematic differences across rural or urban patients with respect to pneumonia severity. Rural patients were more likely to be treated by a family physician and somewhat less likely to be admitted to an intensive care unit or to be mechanically ventilated. Costs of treating rural patients were lower. In-hospital mortality rates, with controls for admission severity, were comparable or better for rural patients than for urban patients.

CONCLUSIONS

Patients with CAP are treated in hospitals located in counties similar to ones in which they reside. The cost of treatment was lower for rural patients than for urban patients, but outcomes were not different.

Spinal cord ependymomas: MR imaging features

PURPOSE

To assess the magnetic resonance (MR) imaging characteristics of spinal intramedullary ependymomas.

MATERIALS AND METHODS

MR images obtained in 25 patients (aged 12-73 years) with proved intramedullary ependymomas were retrospectively reviewed. T1- and T2-weighted images were obtained in all patients. Gadopentetate dimeglumine was intravenously administered in 23 patients; enhanced sagittal and axial T1-weighted spin-echo images were reviewed.

RESULTS

All tumors had hyperintense signal on T2-weighted images. In the 23 patients who received contrast material, all tumors became enhanced; enhancement was heterogeneous in 15 patients and homogeneous in eight patients. Twenty tumors had sharply defined, enhanced borders. Nineteen tumors were centrally located in the spinal cord. A hypointense rim on T2-weighted images was noted in five patients.

CONCLUSION

Intramedullary ependymomas become enhanced after administration of gadopentetate dimeglumine; the enhanced borders are usually sharply marginated. They are characteristically located centrally in an expanded spinal cord. Hemosiderin is often present at the periphery of cervical ependymomas.

Variation in the use of red blood cell transfusions. A study of four common medical and surgical conditions

This study assessed variation in red cell transfusion practice among adult patients hospitalized with ulcer disease (ULCER), and those undergoing coronary artery bypass grafting (CABG), hip surgery (HIP), or total knee replacement (KNEE). The study design was a retrospective analysis of the 1989 MedisGroups Hospital Comparative Database, and the participants were adult patients presenting for their first admission with ULCER (N = 4,664), CABG (N = 6,812), HIP (N = 4,131) or KNEE (N = 3,042) in the MedisGroups Hospital Comparative Database. Outcome measures were whether a patient was transfused, and the number of units transfused. Logistic regression was used to analyze the decision to transfuse, and linear regression to analyze the number of units transfused. In these analyses, patient characteristics, hospital characteristics, and unique hospital identity were used as independent variables. The percentage of patients transfused was ULCER 50%, CABG 81%, HIP 69%, and KNEE 51%. The range among hospitals in the percentage of patients transfused was ULCER 11% to 76%, CABG 51% to 100%, HIP 36% to 95%, and KNEE 9% to 97%. When only patient characteristics were entered in the linear regression analyses, the R2 values were ULCER 0.33, CABG 0.11, HIP 0.11, and KNEE 0.07. When hospital was added, the R2 increased to ULCER 0.38, CABG 0.29, HIP 0.19, and KNEE 0.20 (P < 0.0001 for the change for all analyses). The results of the logistic regression analyses of the probability of transfusion were similar. There is substantial interhospital variation in the proportion of patients transfused and number of units transfused in the four conditions studied. Patient demographic and clinical characteristics explain a substantial proportion of the variation in transfusion practices for ulcer patients, but little of the variation in the three surgical conditions.

Comparison of a disease-specific and a generic severity of illness measure for patients with community-acquired pneumonia

OBJECTIVE

To compare the performances of a disease-specific severity of illness index and a prototypical generic severity of illness measure, MedisGroups Admission Severity Groups (ASGs), for patients with community-acquired pneumonia.

DESIGN

A retrospective database study.

PATIENTS

Adult patients (aged > or = 18 years) with an ICD-9-CM principal diagnosis of pneumonia in 78 MedisGroups Comparative Database hospitals.

METHODS

The pneumonia severity of illness index (PSI) was developed to predict hospital mortality using logistic regression analyses in a 70% random sample of study patients. The performances of the PSI and the generic severity measure were assessed among the remaining 30% of patients by comparing observed mortalities within the five PSI and ASG severity classes, and areas under their receiver operating characteristic (ROC) curves. Both the PSI and the generic severity measure were used to estimate the 95% confidence interval of the expected number of deaths in each of the 78 study hospitals. Hospitals with an observed number of deaths outside these limits were identified as outliers.

RESULTS

There were 14,199 study patients who had community-acquired pneumonia, and 1,542 (10.9%) died during hospitalization. In comparison with the generic severity measure, the PSI more accurately identified patients at extremely low risk of death, and had a larger area under its ROC curve (0.84 vs 0.79; p < 0.0001). Of the 78 study hospitals, 17 (21.8%) were classified as outliers for mortality by at least one severity adjustment system. Among the 11 low-outlier hospitals, six were classified by the generic severity measure alone, two by the PSI alone, and three by both systems; among the six high-outlier hospitals, one was classified by the generic measure alone, three by the PSI alone, and two by both systems.

CONCLUSIONS

The PSI provided more accurate estimates of hospital mortality and classified different hospital outliers for mortality than did the generic severity of illness measure for patients with community-acquired pneumonia.

Propensity score adjustment for pretreatment differences between hospitalized and ambulatory patients with community-acquired pneumonia. Pneumonia Patient Outcomes Research Team (PORT) Investigators

A primary goal of the Pneumonia Patient Outcomes Research Team (PORT) multicenter cohort study is to identify a subgroup of patients with community-acquired pneumonia (CAP) who could be safely treated on an ambulatory basis. The medical outcomes of inpatients and outpatients are to be compared. Propensity score adjustment provides a unified way to control for pretreatment differences in the analysis of all the outcomes in this nonrandomized study by defining "comparable" patients as those with the same propensity score (i.e., the same probability of hospitalization). Data for 747 patients (35.5% hospitalized) with CAP in the Pneumonia PORT study illustrate the development and assessment of a propensity score adjustment. A classification tree algorithm defined seven propensity score strata with hospitalization probabilities ranging from 6.5% to 76.5%. Statistically significant pretreatment imbalances favoring the outpatients were found for 29 of 44 baseline variables considered; after stratification on the propensity score, only 13 of the 29 imbalances remained statistically significant at the 0.05 level. Post hoc stratification on the estimated propensity score consistently reduced, but did not completely eliminate, systematic baseline differences between ambulatory and hospitalized patients with CAP. Regression adjustment can be used in conjunction with propensity score stratification to adjust further for the remaining identified imbalances.

Clinically unsuspected venous malformations limited to the submandibular triangle: CT findings

PURPOSE

To present the CT characteristics of histologically confirmed venous vascular malformations limited to the submandibular triangle in patients without clinical stigmata of venous vascular malformations.

METHODS

The clinical records and CT scans of five women with venous vascular malformations limited to the submandibular triangle were reviewed. Patients ranged from 39 to 70 years of age. None of the patients had a history of malignant tumors. All patients presented with a solitary suprahyoid neck mass. None of the patients demonstrated cutaneous manifestations of venous vascular malformation.

RESULTS

Contrast-enhanced CT scans in all five patients demonstrated a lobulated, heterogeneously enhancing, well-circumscribed solid mass, separable from the submandibular gland. Areas of contrast enhancement within each mass were isodense to the internal jugular vein in four of five cases. Only two of five lesions demonstrated focal calcifications. Excisional biopsy (two patients) demonstrated pathologic features compatible with venous vascular malformation. Fine needle aspirations (three patients) yielded venous blood or blood-tinged fluid.

CONCLUSIONS

Venous vascular malformations may present as isolated neck masses in adults without typical clinical stigmata. Clues to the CT diagnosis include a lobulated appearance to the mass with intense but heterogeneous contrast enhancement. This appearance, in combination with results of fine needle aspiration, may be sufficiently diagnostic to preclude excisional biopsy.

The use of misclassification costs to learn rule-based decision support models for cost-effective hospital admission strategies

Cost-effective health care is at the forefront of today's important health-related issues. A research team at the University of Pittsburgh has been interested in lowering the cost of medical care by attempting to define a subset of patients with community-acquire pneumonia for whom outpatient therapy is appropriate and safe. Sensitivity and specificity requirements for this domain make it difficult to use rule-based learning algorithms with standard measures of performance based on accuracy. This paper describes the use of misclassification costs to assist a rule-based machine-learning program in deriving a decision-support aid for choosing outpatient therapy for patients with community-acquired pneumonia.