Epidemiology of community-acquired pneumonia in older adults: a population-based study

OBJECTIVE: This study assessed incidence, aetiology, clinical outcomes and risk factors for community-acquired pneumonia (CAP) in older adults. METHODS: This was a population-based cohort study that included 11,241 community-dwelling individuals aged 65 years or more, who were followed between 2002 and 2005 in the region of Tarragona, Spain. Primary endpoints were all-cause CAP (hospitalised and outpatient) and 30-day mortality after the diagnosis. All cases were radiographically proved and validated by checking clinical records. RESULTS: Incidence rate of overall CAP was 14 cases per 1000 person-years (10.5 and 3.5 for hospitalised and outpatient cases, respectively). Incidence was almost three-fold higher among immunocompromised patients (30.9 per 1000) than among immunocompetent subjects (11.6 per 1000). Maximum incidences were observed among patients with chronic lung disease and long-term corticosteroid therapy (46.5 and 40.1 cases per 1000 person-years, respectively). Overall 30-day case-fatality rate was 12.7% (2% in cases managed as outpatient and 15% in hospitalised patients). Among 358 patients with an aetiological work-up, a total of 142 pathogens were found (single pathogen in 121 cases and mixed pathogens in 10 cases). Streptococcus pneumoniae was the most common pathogen (49%), followed by Pseudomonas aeruginosa (15%), Chlamydia pneumoniae (9%) and Haemophilus influenzae (6%). In multivariable analysis, the variables most strongly associated with increasing risk of CAP were history of hospitalisation for CAP in the previous 2 years and presence of any chronic lung disease. CONCLUSIONS: CAP remains a major cause of morbidity and mortality in older adults. Incidence rates in this study largely doubled prior rates reported in Southern European regions.     

Risk factors for community-acquired pneumonia in adults: a population-based case-control study.

Although community-acquired pneumonia (CAP) remains a major cause of hospitalization and death, few studies on risk factors have been performed. A population-based case-control study of risk factors for CAP was carried out in a mixed residential-industrial urban area of 74,610 adult inhabitants in the Maresme (Barcelona, Spain) between 1993 and 1995. All patients living in the area and clinically suspected of having CAP at primary care facilities and hospitals were registered. In total, 205 patients with symptoms, signs and radiographic infiltrate compatible with acute CAP participated in the study. They were matched by municipality, sex and age with 475 controls randomly selected from the municipal census. Risk factors relating the subject's characteristics and habits, housing conditions, medical history and treatments were investigated by means of a questionnaire. In the univariate analysis, an increased risk of CAP was associated with low body mass index, smoking, respiratory infection, previous pneumonia, chronic lung disease, lung tuberculosis, asthma, treated diabetes, chronic liver disease, and treatments with aminophiline, aerosols and plastic pear-spacers. In multivariate models, the only statistically significant risk factors were current smoking of >20 cigarettes x day(-1) (odds ratio (OR)=2.77; 95% confidence interval (CI) 1.14-6.70 compared with never-smokers), previous respiratory infection (OR=2.73; 95% CI 1.75-4.26), and chronic bronchitis (OR=2.22; 95% CI 1.13-4.37). Benzodiazepines were found to be protective in univariate and multivariate analysis (OR=0.46; 95% CI 0.23-0.94). This population-based study provides new and better established evidence on the factors associated with the occurrence of pneumonia in the adult community.     

Epidemiology of community-acquired pneumonia in adults

Respiratory diseases represent the third cause of death in Chilean population, after cardiovascular diseases and malignancy. Fifty percent of deaths caused by respiratory diseases in adults are attributable to pneumonia. In Chile, they represent the main cause of death due to infectious diseases and the first specific one in senescent adults over 80 years old. The incidence and mortality of community acquired pneumonia (CAP) increase in both extreme ages of life (less than one year old and over 65 years old). In the population over 65 years old, mortality is extremely increased, rising to rates of 6.6 deaths per 1.000 inhabitants. High variability in pneumonia hospitalization rate has been observed in different geographic areas, probably due to different medical criteria used to evaluate the severity of illness, access to healthcare systems and characteristics of the evaluated population. About 20% of patients affected with CAP require hospitalization due to the severity of pulmonary infection and to the risk of complications or death, and the necessity of healthcare resources are focused in these patients. Several clinical-epidemiological parameters able to modify clinical presentation and severity of pneumonia have been identified, such as advanced age, presence of co-morbidities, host immune competence, tobacco and alcohol consumption, place of acquiring the infection, etiology and environmental pollution.     

Prognosis after community-acquired pneumonia in the elderly: a population-based 12-year follow-up study.

BACKGROUND: Only a few studies have investigated the long-term effects of community-acquired pneumonia (CAP). These studies have focused on cases treated in the hospital, and, to our knowledge, no long-term survival studies that include all cases of CAP are available. METHODS: A prospective observational study on the survival rates in a population-based cohort of elderly inhabitants aged 60 years or older at baseline in 1 township in eastern Finland in 1983. A total of 4167 (99% of the total elderly population), 122 of whom survived CAP during a prospective pneumonia surveillance period from 1983 to 1985, were followed up for mortality from 1983 to 1994 for a median of 9.2 years. The relative risk (RR) of death in patients who survived CAP was compared with that in elderly inhabitants without CAP by Cox multivariate regression analysis. Data on causes of death were obtained from a central register based on death certificates. RESULTS: The long-term survival rate was significantly lower in persons who had survived CAP or pneumococcal CAP (PCAP) than in the rest of the study population. The RR of pneumonia-related mortality was 2.1 (95% confidence interval [CI], 1.3-3.4; P = .004) in all patients with CAP and 2.8 (95% CI, 1.5-5.3; P = .001) in patients with PCAP. The respective numbers for total mortality were 1.5 (95% CI, 1.2-1.9; P = .001) in all patients with CAP and 1.6 (95% CI, 1.1-2.2; P= .01) in those with PCAP. Also the risk of cardiovascular mortality was increased in persons with CAP (RR, 1.4; 95% CI, 1.0-1.9; P = .02) and in those with PCAP (RR, 1.6; 95% CI, 1.0-2.4; P= .04). CONCLUSIONS: The present results indicate that elderly patients treated for CAP are at high risk of subsequent mortality for several years. Based on the high incidence and negative long-term effects of pneumonia, it can be concluded that there is a clear need for prevention, eg, by influenza and pneumococcal immunization.     

Severe community-acquired pneumonia in adults

Patients with severe community acquired pneumonia (CAP) need continuous surveillance and monitoring at intensive care units (ICU), where they can receive specialized support as mechanical ventilation and/or hemodynamic support. Patients that require ICU admittance represent 10 to 30% of all patients interned because a pneumonia. In this category, high complication rate, prolonged hospital stay and high mortality rate are the rule. The American Thoracic Society (ATS) criteria for severe pneumonia establishes the following main criteria: necessity of mechanical ventilation and presence of septic shock; minor criteria: systolic blood pressure < 90 mmHg, radiological multilobar involvement and PaO2/FiO2 < 250 mmHg. British Thoracic Society (BTS) criteria for severe CAP are: respiratory rate over 30 breaths/min, diastolic blood pressure under 60 mmHg, BUN > 20 mg/dl and mental confusion. In all patients with CAP it is recommended the evaluation of its severity at admission. This evaluation should be done in conjunction with an experienced physician, and if criteria for poor prognosis are met, an early admission to ICU is recommended. ATS and BTS modified criteria (CURB) are useful in this procedure. In severely ill patients with CAP it is recommended to perform the following microbiological analysis: sputum Gram stain and culture, blood culture, pleural fluid Gram stain and culture, if present and tapped, Legionella pneumophila urine antigen test, influenza A and B antigen detection tests (epidemic period: autumn and winter), and serology for atypical bacteria (Mycoplasma pneumoniae and Chlamydia pneumoniae).     

Severe community-acquired pneumonia. Epidemiology and prognostic factors

Over a period of 4 consecutive yr, 92 nonimmunosuppressed patients (21 women and 71 men aged 53 +/- 16 yr, means = SD) with critical acute respiratory failure (PaO2/FiO2, 209 +/- 9 mm Hg) caused by severe community-acquired pneumonia were admitted to the respiratory intensive care unit (RICU) of a general hospital. The most frequent underlying clinical condition was chronic obstructive pulmonary disease (44 patients, 48%). A total of 56 patients (61%) required mechanical ventilation for a mean period of 10.7 +/- 12.5 days, 29 of them (52%) needing PEEP (9.9 +/- 3.8 cm H2O). A group of 23 (25%) patients had criteria of adult respiratory distress syndrome (ARDS). A causal microorganism was identified in 48 patients (52%), the two most frequent etiologies being Streptococcus pneumoniae (14, 15%) and Legionella pneumophila (13, 14%). Pseudomonas aeruginosa (5, 5%) was always associated with bronchiectasis. Mortality due to severe community-acquired pneumonia was 22% (20 patients). According to univariate analysis, mortality was associated with anticipated death within 4 to 5 yr, inadequate antibiotic treatment before RICU admission, mechanical ventilation requirements, use of PEEP, FIO2 greater than 0.6, coexistence of ARDS, radiographic spread of the pneumonia during RICU admission, septic shock, bacteremia, and P. aeruginosa as the cause of the pneumonia. Further, recursive partitioning analysis selected two factors significantly related to the prognosis: the radiographic spread of the pneumonia during RICU admission and the presence of septic shock.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiology and etiology of community-acquired pneumonia

The seriousness of community-acquired pneumonia (CAP), despite being a reasonably common and potentially lethal disease, often is under estimated by physicians and patients alike. CAP results in more than 10 million visits to physicians, 64 million days of restricted activity, and 600,000 hospitalizations. This article discusses the epidemiology and bacterial causes of CAP in immunocompetent adults and the severe acute respiratory syndrome coronavirus.     

Epidemiology of community-acquired pneumonia in the elderly

The attack rate for pneumonia increases with increasing age and with residence in a nursing home. The rate of hospitalization of Halifax County, Nova Scotia, Canada, residents with pneumonia was 1 in 1,000, while for nursing home residents it was 33 in 1,000. The overall mortality rate for community-acquired pneumonia requiring hospitalization was 21.9%. Mortality was age-related: Seven percent of those 30 years of age or younger died, while 38% of those in the 81 to 90 year age group died. Comorbidities increased with increasing age from 0.73 +/- 0.81 for those 30 years old or younger to 2.75 +/- 1.47 for those 71 to 80 years of age. The most common comorbidities were chronic obstructive pulmonary disease, ischemic heart disease, hypertension, diabetes mellitus, malignancy, alcoholism, and neurological disease. The acquired immunodeficiency syndrome was a significant comorbidity among those 50 years of age or younger. Age-dependent trends were observed in the use of antimicrobial therapy: Cefamandole and aminoglycosides were prescribed more frequently with increasing age, whereas after the age of 61 years, the use of erythromycin declined. Penicillin usage was not age-dependent. Resource (hemograms, chest radiographs, blood chemistry, blood gases, and sputum culture) use peaked at the 50 to 60 year age group.     

Differences in the etiology of community-acquired pneumonia according to site of care: a population-based study

BACKGROUND: A few population-based studies assessing the etiology of community-acquired pneumonia in both hospitalized and ambulatory patients, with special emphasis on the etiologic role of viral infections, have been reported. The purpose of this study was to assess microbiological differences according to initial site of care in patients with community-acquired pneumonia. METHODS: We studied 496 patients > 14 years of age collected from the study samples of three population-based studies carried out in the same geographical area ("Maresme" region in the Mediterranean coast in Barcelona, Spain) with the same methodology over an 8-year period (1987-1995). RESULTS: Fifty-six percent of patients were hospitalized and 44% were treated at home. Of the 474 patients with etiological evaluation, 195 patients had an identifiable etiology (overall diagnostic yield 41%). Streptococcus pneumoniae was the most common causative organism. Viral infection was diagnosed in 26.5% of hospitalized patients vs. 13.2% of ambulatory patients (P=0.03). Twenty-five percent of the 68 patients with documented etiology treated at home had Chlamydia pneumoniae infection compared with 14.3% of those treated in the hospital. Ten percent of hospitalized patients had pneumonia caused by two pathogens compared with 9.7% of ambulatory patients. The association of viruses and bacteria was the most frequent cause of dual infection (79% inpatients, 67% outpatients). CONCLUSIONS: This study has provided information on etiology of community-acquired pneumonia in hospitalized patients and in patients treated at home. A considerable proportion of patients had viral pneumonia, frequently requiring hospital admission for inpatient care.     

Treatment of community-acquired pneumonia in adults

Appropriate antibiotic treatment reduces the duration of symptoms associated to pneumonia, the risk of complications and mortality. In most cases, it is not possible to identify the etiologic agent so antibiotic treatment is empirically prescribed. In Chile, one third of Streptococcus pneumoniae strain isolates has diminished susceptibility to penicillin; in-vitro erythromycin resistance is about 10-15% and cefotaxime resistance 2-10%. It is recommended to classify patients with community acquired pneumonia in four risk categories: Group 1: patients under 65 years without co-morbidities, in ambulatory attendance. Treatment: oral amoxicillin 1 g TID, 7 days. Group 2: patients over 65 years and / or co-morbidities, in ambulatory attendance. Treatment: oral amoxicillin/clavulanate 500/125 mg TID or 875/125 mg BID, or cefuroxime 500 mg BID, 7 days. Group 3: patients admitted to general wards with criteria of moderate severity. Treatment: ceftriaxone 1-2 g once a day or cefotaxime 1 g TID, IV, 7-10 days. Group 4: patients with severe CAP that must be interned into ICU. Treatment: ceftriaxone 2 g once a day or cefotaxime 1 g TID, IV, associated to erythromycin 500 QID, levofloxacin 500-1.000 mg once a day, or moxifloxacin 400 mg/once a day, IV, 10-14 days. In the presence of allergy to or treatment failure with betalactam drugs and/or positive serology for Mycoplasma, Chlamydia or Legionella sp it is recommended to add: erythromycin 500 mg QID, IV or oral, oral clarithromycin 500 mg BID, or oral azythromycin 500 mg once a day.     

Prevention of community-acquired pneumonia in adults

Polysaccharide 23 valent pneumococcal vaccine commercially available from 1983 includes 23 serotypes of Streptococcus pneumoniae, representing near 90% of strains involved in invasive pneumococcal disease in immune competent adults. Vaccine confers protection against invasive pneumococcal disease. Immunization is recommended in adults over 65 years old, in patients affected by chronic diseases (cardiopathies, COPD, nephropathies, diabetes mellitus, hepatic cirrhosis, chronic breakage in brain-blood barrier, functional or anatomical asplenia, alcoholism), in immunocompromised hosts, including HIV infection, chemotherapy treatment and hematological malignancies. Influenza vaccine is prepared with particulated antigens, including two influenza A strains and one influenza B strain, selected according to influenza epidemiological worldwide surveillance the year before. On account of continuous antigenic changes (drifts), it is necessary to modify the vaccine antigen's composition yearly. Cost/effectiveness evaluation has confirmed the efficacy of influenza vaccine in reducing morbidity and mortality associated to influenza epidemic and health economical resources involved in patient care. Besides, clinical trials have confirmed that immunization reduces the risk of acquiring pneumonia, of hospitalization and death in elderly people during the influenza epidemic, when vaccine antigenic composition is similar to the circulating strains. Vaccination is recommended annually in healthy adults over 65 years old, in patients with chronic diseases (cardiopathies, COPD, nephropathies, diabetes mellitus, hepatic cirrhosis, chronic breakage of blood-brain barrier, functional or anatomical asplenia, alcoholism). It is also recommended in women who will be in the second or third trimester of pregnancy during the influenza season, in immunocompromised hosts, in institutionalized patients (geriatrics), health care workers, and travelers to geographical areas that are affected by the influenza epidemic.     

Viral community-acquired pneumonia in nonimmunocompromised adults

INTRODUCTION: Viral community-acquired pneumonia (CAP) has been poorly studied and clinically characterized. Using strict criteria for inclusion, we studied this type of infection in a large series of hospitalized adults with CAP. MATERIALS AND METHODS: All nonimmunocompromised adult patients with a diagnosis of CAP having paired serology for respiratory viruses (RVs) [338 patients] were prospectively included in the study from 1996 to 2001 at our 1,000-bed university teaching hospital, and subsequently were followed up. We compared patients with pure viral (PV), mixed viral (RV + bacteria), and pneumococcal CAP. RVs (ie, influenza, parainfluenza, respiratory syncytial virus, and adenovirus) were diagnosed by means of paired serology. RESULTS: Sixty-one of 338 patients (18%) with paired serology had an RV detected, and in 31 cases (9%) it was the only pathogen identified. Influenza was the most frequent virus detected (39 patients; 64%). Patients with chronic heart failure (CHF) had an increased risk of acquiring PV CAP (8 of 26 patients; 31%) when compared to a mixed viral/bacterial etiology (2 of 26 patients; 8%; p = 0.035) or CAP caused by Streptococcus pneumoniae (1 of 44 patients; 2%; p = 0.001). Multivariate analysis revealed that CHF (odds ratio [OR], 15.3; 95% confidence interval [CI], 1.4 to 163; p = 0.024) and the absence of expectoration (OR, 0.14; 95% CI, 0.04 to 0.6; p = 0.006) were associated with PV pneumonia compared to pneumococcal CAP. CONCLUSION: RVs are frequent etiologies of CAP (single or in combination with bacteria). Patients with CHF have an increased risk of acquiring a viral CAP.     

Use of proton pump inhibitors and the risk of community-acquired pneumonia: a population-based case-control study

BACKGROUND: Recently, the use of proton pump inhibitors (PPIs) has been associated with an increased risk of pneumonia. We aimed to confirm this association and to identify the risk factors. METHODS: We conducted a population-based case-control study using data from the County of Funen, Denmark. Cases (n=7642) were defined as all patients with a first-discharge diagnosis of community-acquired pneumonia from a hospital during 2000 through 2004. We also selected 34 176 control subjects, who were frequency matched to the cases by age and sex. Data on the use of PPIs and other drugs, on microbiological samples, on x-ray examination findings, and on comorbid conditions were extracted from local registries. Confounders were controlled by logistic regression. RESULTS: The adjusted odds ratio (OR) associating current use of PPIs with community-acquired pneumonia was 1.5 (95% confidence interval [CI], 1.3-1.7). No association was found with histamine(2)-receptor antagonists (OR, 1.10; 95% CI, 0.8-1.3) or with past use of PPIs (OR, 1.2; 95% CI, 0.9-1.6). Recent initiation of treatment with PPIs (0-7 days before index date) showed a particularly strong association with community-acquired pneumonia (OR, 5.0; 95% 2.1-11.7), while the risk decreased with treatment that was started a long time ago (OR, 1.3; 95% CI, 1.2-1.4). Subgroup analyses revealed high ORs for users younger than 40 years (OR, 2.3; 95% CI, 1.3-4.0). No dose-response effect could be demonstrated. CONCLUSION: The use of PPIs, especially when recently begun, is associated with an increased risk of community-acquired pneumonia.     

Prevalence of legionellosis among adults: A study of community-acquired pneumonia in France

Summary Over a 24-month period, 274 patients with community-acquired pneumonia were hospitalized in Departments of Medicine at hospitals in Bordeaux, Lyon, Marseille, and Toulouse. Etiology of the pneumonia was determined either by organism identification or by indirect immunofluorescence in only 139 cases (51%). The most frequently isolated etiological agents wereStreptococcus pneumoniae (34 cases),Legionella pneumophila (29 cases) andMycoplasma pneumoniae (24 cases). The majority of patients with legionellosis were male (79%), middle aged (mean age: 53 years), and living in urban areas (69%). Their clinical features were atypical and did not differ from those of other pneumonias. Four patients with legionellosis (13.8%) died.L. pneumophila was isolated directly in only three instances. The study confirms the high prevalence of legionellosis (20%) among pneumonias of identified etiology. The fact that these cases had an atypical clinical presentation and that isolation of the organism was difficult reinforce the need to apply the CDC criteria for the interpretation of positive serological titers.

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Prävalenz der Legionellose bei Erwachsenen. Studie zur nosokomialen Pneumonie in Frankreich

Zusammenfassung In einem Zeitraum von 24 Monaten wurden 274 Patienten mit nosokomialer Pneumonie in internen Abteilungen von Kliniken in Bordeaux, Lyon, Marseille und Toulouse stationär behandelt. Die ätiologische Diagnose der Pneumonie konnte durch Identifizierung des Erregers oder indirekte Immunfluoreszenz nur bei 139 Fällen (51%) gestellt werden. Die häufigsten Erreger warenStreptococcus pneumoniae (34 Fälle),Legionella pneumophila (29 Fälle) undMycoplasma pneumoniae (24 Fälle). Bei den Patienten mit Legionellose waren Männer in der Überzahl (79%), das mittlere Alter betrug 53 Jahre, 69% der Patienten lebten in Städten. Die klinischen Symptome waren uncharakteristisch und unterschieden sich nicht von denen anderer Pneumonien. Vier der an Legionella-Pneumonie erkrankten Patienten verstarben (13,8%).L. pneumophila wurde nur in drei Fällen direkt isoliert. Die vorliegende Untersuchung bestätigt die hohe Prävalenz der Legionellose bei Pneumonien definierter Ätiologie (20%). Die Tatsache, daß diese Fälle ein atypisches klinisches Bild aufwiesen und daß die Erregerisolation schwierig war, bestätigen die Notwendigkeit, positive serologische Befunde nach den CDC-Kriterien zu interpretieren.

     

Etiology of community-acquired pneumonia in immunocompetent adults

In an ideal clinical setting, empiric antimicrobial treatment prescribed in adult community acquired pneumonia (CAP) should be based on national etiological surveillance and in vitro susceptibility assays. Available information about etiology in ambulatory patients and intensive care unit (ICU) patients is scarce, compared to information obtained in hospitalized patients. In studies designed to explore the etiology of pneumonia, no microorganism is detected in 40-50% of patients, a fact that represents limited yields in diagnostic methods. In all settings, Streptococcus pneumoniae is the main respiratory pathogen recovered in adults CAP, being responsible of about 16% of cases among ambulatory patients and about 22% of those admitted to hospital and ICU. About one third of cases are caused by a small group of microorganisms: Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae, respiratory viruses, Staphylococcus aureus, gramnegative bacillus, Legionella sp; each one is isolated in less than 10% of cases. In general, microorganism distribution varies scarcely in the following attending settings: ambulatory patients, common wards and ICU. An exception is represented by a higher frequency of gram negative bacillus, S. aureus and Legionella sp in ICU, and of C. pneumoniae in the ambulatory setting. In Chile, CAP etiology in hospitalized adult patients is similar to foreign reports; no systematic information has been collected about the etiology in neither ambulatory patients nor in severe CAP.     

Microbiologic diagnosis of community-acquired pneumonia in adults

Microbiological analysis allows us to identify the etiology of pneumonia and its in vitro susceptibility pattern. Antibiotic treatment directed against a known pathogen enables us to narrow antibacterial spectrum of action, and to reduce costs, drug adverse effects risk and antibiotic resistance. However it is unnecessary to perform extended microbiological studies in all patients with community acquired pneumonia (CAP). Etiological studies must be based in pneumonia severity, epidemiological risk factors and clinical response to empirical treatment. Routine microbiological analysis for ambulatory patients is not recommended. In patients with persistent cough and worsening in their general conditions, a sputum sample must be obtained to perform an acid-fast smear and Mycobacterium culture. The risk of complications and death of patients hospitalized with CAP justifies basic microbiological exploration (sputum Gram staining and culture, blood cultures, pleural fluid culture) intending to obtain a more accurate etiology of pulmonary infection and to guide specific antibiotic treatment. Paired serum samples obtained to document atypical pathogen infections (Mycoplasma pneumoniae, Chlamydia pneumoniae) and urine sample to detect Legionella pneumophila antigenuria are recommended in all CAP severely ill patients that are admitted to ICU, in those not responding to betalactamic drug treatment and in selected patients with specific epidemiological risks. A microbiological study would be useful in management of patients with severe CAP pneumonia outbreaks with clinical-epidemiological particular characteristics, and in-patients with empirical antimicrobial treatment failure.     

Evaluating severity of community-acquired pneumonia in adults

Clinical evolution in patients affected by community acquired pneumonia varies from a mild and low risk infectious disease to an extremely severe, life threatening disease. Commonly, immunocompetent adults without co-morbidities or severe risk factors cared for at out patient clinic have low risk of complications and death (mortality below 1-2%); it increases to 5-15% in patients with co-morbidities and/or with specific risk factors that are admitted into the hospital and reaches 20-50% in those patients admitted into ICUs. Evaluation of severity in patients with pneumonia allows the prediction of disease evolution, establishing the proper setting of care, the type- of microbiological tests needed, and to choose the best empiric antibiotic treatment. It is suggested that patients be in three risk categories: low risk (mortality under 1-2%) susceptible to ambulatory treatment; high risk patients (mortality 20-30%) that need specialized wards; and intermediate risk patients, with co-morbidities and/or risk factors for complicated clinical evolution and death, but cannot be classified in a specific category. In the ambulatory setting, without availability of complete laboratory exams, it is recommended to evaluating the severity of pneumonia considering the following clinical variables: age over 65 years, presence of co-morbidities, sensorial compromise, vital signs alteration, degree of radiological involvement: multilobar, bilateral findings, cavitations), pleural effusion and arterial oximetry < 90%. However, clinical judgement and the physician's experience must predominate over predictive models, which are not infallible.     

In-hospital management of adults who have community-acquired pneumonia.

The initial in-hospital management of adult patients with community-acquired pneumonia can be divided into five major steps: an early recognition of the patient with presumptive pneumonia, assessment of the severity of illness, establishment of an etiologic diagnosis, supportive therapy, and decision regarding initiation of empirical therapy. In most European recommendations, the empirical antibiotic treatment is directed against "the most likely pathogen," based on epidemiological, clinical, and laboratory data, and on the severity of illness. In contrast, newer North American guidelines have focused on the severity of illness of community-acquired pneumonia. As a consequence, the use of a broader initial antibiotic coverage, including extended-spectrum cephalosporins and combinations, seems to be more common in North America than in Europe.