Efficacy of pneumococcal vaccination in adults. A meta-analysis of randomized controlled trials.

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.

Assessing prognosis and predicting patient outcomes in community-acquired pneumonia.

Community-acquired pneumonia is a common medical illness, with clinical outcomes ranging from mild illness with rapid and complete recovery to a fulminant clinical course with morbid complications followed by death. A systematic review of the literature on pneumonia prognosis has identified a variety of demographic factors, symptoms and physical examination findings, comorbid illnesses, laboratory abnormalities, and etiologic agents that are independently associated with short-term mortality in patients with this illness. By combining these prognostic factors, investigators have developed a variety of indices to predict short-term mortality. Although these predictive instruments vary with respect to the patient populations studied, number of predictor variables included, statistical methods used, and overall clinical performance, these models can assist physicians in assessing patient prognosis and in making important management decisions such as the initial site of care (ie, home v hospital). Assessment of patient prognosis has also been used by clinicians and health services researchers who use the hospital severity of illness-adjusted mortality rate as a measure of the quality of medical care provided. Because the majority of patients with this illness survive, future assessments or predictions of prognosis in patients with community-acquired pneumonia should also evaluate a spectrum of other important health outcome measures including the occurrence of morbid complications, symptom resolution, quality of life, return to work and usual activities, and patient satisfaction with care.

Cholesterol crystal embolization: a review of 221 cases in the English literature.

Cholesterol crystal embolization (CCE) frequently presents with nonspecific manifestations that mimic other systemic diseases. The authors reviewed 221 cases of histologically proven CCE in the English literature to define the clinical, laboratory, and pathologic characteristics of this disorder. CCE affected predominantly elderly males (mean age sixty-six) with a frequent history of hypertension (61%), atherosclerotic cardiovascular disease (44%), renal failure (34%), and aortic aneurysms (25%) at presentation. At least one possible predisposing factor was present in 31% and included operative and radiological vascular procedures and the use of anticoagulants. Cutaneous findings (34%) and renal failure (50%) were two of the most common clinical findings throughout the course of CCE. The nonspecific signs and symptoms included: fever (7%), weight loss (7%), myalgias (4%), and headache (3%). Premortem diagnoses were established in 31% of patients most commonly by biopsy of the muscle, skin, and kidney. Mortality was high (81%) and was most commonly due to multifactorial, cardiac, and renal etiologies. The authors conclude that CCE should be strongly considered in elderly patients with atherosclerotic vascular disease who have the onset of renal insufficiency and cutaneous manifestations. CCE may be confirmed by a skin or muscle biopsy.