RESUMEN
BACKGROUND: Because of the prevalence of pneumococcal pneumonia, the substantial morbidity and mortality associated with many pneumococcal infections, and an increase in the incidence of antibiotic resistance among pneumococcal isolates, considerable efforts for disease prevention have been made using a polyvalent polysaccharide pneumococcal vaccine. Despite numerous clinical trials of the vaccine, its efficacy in the prevention of pneumococcal infections and other clinically relevant medical outcomes in adults remains uncertain. METHODS: To assess quantitatively the efficacy of pneumococcal vaccination, a MEDLINE literature search, manual reviews of article bibliographies, and communications with pneumococcal vaccine investigators were used to identify randomized controlled trials of the pneumococcal vaccine. Independent review of 594 articles revealed nine randomized trials with 12 vaccine and control study groups that evaluated clinically relevant outcomes in adults. To estimate a summary effect size for all outcomes, Mantel-Haenszel odds ratios (ORs) and Dersimonian and Laird rate differences (RDs) and their associated 95% confidence intervals (CIs) were computed. RESULTS: Summary ORs demonstrated a statistically significant protective effect of the vaccine for four pneumococcal infection-related outcomes: definitive pneumococcal pneumonia (OR = 0.34; 95% CI = 0.24 to 0.48), definitive pneumococcal pneumonia for vaccine-containing pneumococcal antigen types only (vaccine types only) (OR = 0.17; 95% CI = 0.09 to 0.33), presumptive pneumococcal pneumonia (OR = 0.47; 95% CI = 0.35 to 0.63), and presumptive pneumococcal pneumonia (vaccine types only) (OR = 0.39; 95% CI = 0.26 to 0.59). The summary RDs, which account for heterogeneity among studies, confirmed a statistically significant protective effect for two of these same outcomes: definitive pneumococcal pneumonia (RD = 4/1000; 95% CI = 0/1000 to 7/1000) and definitive pneumococcal pneumonia (vaccine types only) (RD = 8/1000; 95% CI = 1/1000 to 16/1000). Summary ORs and RDs failed to demonstrate a protective effect for pneumonia (all causes), bronchitis, and mortality (all causes) or mortality due to pneumonia or pneumococcal infection. Subgroup analyses showed that for all four pneumococcal infection-related outcomes, vaccine efficacy differed for high- and low-risk subjects, demonstrating efficacy for low-risk subjects and lack of efficacy for high-risk subjects. CONCLUSIONS: Pneumococcal vaccination appears efficacious in reducing bacteremic pneumococcal pneumonia in low-risk adults. However, evidence from randomized controlled trials fails to demonstrate vaccine efficacy for pneumococcal infection-related or other medical outcomes in the heterogeneous group of subjects currently labeled as high risk.
Asunto(s)
Vacunas Bacterianas , Infecciones Neumocócicas/prevención & control , Adulto , Humanos , Oportunidad Relativa , Neumonía Neumocócica/prevención & control , Ensayos Clínicos Controlados Aleatorios como Asunto , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: To review the studies on diagnostic evaluation of syncope and to provide an approach to the diagnostic testing and management of this condition. DATA SOURCE: Published studies on the evaluation of syncope in the English language. STUDY SELECTION: Cohort studies and case series of patients presenting with syncope and focused studies of various diagnostic tests such as prolonged electrocardiographic monitoring, electrophysiologic studies, and upright tilt testing. Specific selection criteria were used in the case of prolonged electrocardiographic monitoring, in which all studies had to have performed at least 12 hours of monitoring. DATA EXTRACTION: Studies reviewed by the author. DATA SYNTHESIS: Studies in the 1980s have shown that a cause of syncope is not diagnosed in as many as 47% of the patients presenting with this symptom. When a cause of syncope is established, a history and physical examination lead to the identification of 56% to 85% of the causes. In the remaining patients, arrhythmia detection is a central issue. A major problem with the use of ambulatory electrocardiographic (Holter) monitoring in the diagnosis of arrhythmias is that symptomatic correlation with arrhythmias is rarely found (only 4% of patients). Increasing the duration of monitoring from 24 to 72 hours does not lead to increased yield of symptomatic arrhythmias. Patient-activated intermittent loop recorders that can be worn for several weeks may occasionally show a symptomatic correlation, but they are most useful in patients with multiple recurrences of syncope. Electrophysiologic studies are more likely to be abnormal in patients with underlying heart disease or those who have abnormalities on surface electrocardiogram. The most common abnormality found on electrophysiologic studies is inducible ventricular tachycardia. Upright tilt testing has been used to induce vasovagal syncope in patients with syncope of unknown cause. A positive response has been found in 26% to 87% of patients undergoing this type of testing. The specificity of this test needs to be further investigated. In patients with recurrent syncope of unknown cause, psychiatric evaluation should also be pursued for illnesses such as generalized anxiety disorder, panic disorder, somatization, and major depression. CONCLUSIONS: A directed approach to the evaluation is possible using the studies on diagnostic testing of syncope.
Asunto(s)
Síncope/diagnóstico , Síncope/terapia , Arritmias Cardíacas/complicaciones , Arterias Carótidas/fisiopatología , Estudios de Cohortes , Electrocardiografía , Electrofisiología , Humanos , Síncope/etiologíaRESUMEN
The prevalence, risk factors, and outcomes of delirium were studied in 229 elderly patients. Fifty patients (22%) met criteria for delirium; nondelirious elderly constituted the control group. Abnormal sodium levels, illness severity, dementia, fever or hypothermia, psychoactive drug use, and azotemia were associated with risk of delirium. Patients with three or more risk factors had a 60% rate of delirium. Delirious patients stayed 12.1 days in the hospital vs 7.2 days for controls and were more likely to die (8% vs 1%) or be institutionalized (16% vs 3%). Illness severity predicted 6-month mortality, but the effect of delirium was not significant. Delirium occurs commonly in hospitalized elderly, is associated with chronic and acute problems, and identifies elderly at risk for death, longer hospitalization, and institutionalization. The increased mortality associated with delirium appears to be explained by greater severity of illness.