[Propensity score analysis in observational research: application to a study of prophylaxis against venous thromboembolism]. / L'analyse par score de propension Exemple d'application à une étude observationnelle sur la prophylaxie de la maladie thromboembolique veineuse.

INTRODUCTION: In observational studies, a significant difference in the outcomes between treated and untreated patients may be observed in absence of treatment effect and caused by differences in baseline characteristics. EXEGESIS: Propensity score analysis is a post hoc adjustment method which consists in deriving the conditional probability of receiving the treatment for a patient given his measured baseline characteristics (i.e., the propensity score). Matching each treated patient to an untreated one who has the nearest propensity score tends to balance baseline characteristics between the two groups and reduce the risk for overt bias. Then, the outcomes can be compared between matched treated and untreated patients. CONCLUSION: Propensity score analysis is relevant for clinical conditions and treatments for which randomized controlled trials are unlikely to be conducted. However, propensity analysis cannot adjust for unmeasured characteristics and sensitivity analysis should be performed to assess how sensitive the conclusions are to potential confounding factors.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.