Diagnostic and prognostic accuracy of clinical and laboratory parameters in community-acquired pneumonia

BACKGROUND: Community-acquired pneumonia (CAP) is the most frequent infection-related cause of death. The reference standard to diagnose CAP is a new infiltrate on chest radiograph in the presence of recently acquired respiratory signs and symptoms. This study aims to evaluate the diagnostic and prognostic accuracy of clinical signs and symptoms and laboratory biomarkers for CAP. METHODS: 545 patients with suspected lower respiratory tract infection, admitted to the emergency department of a university hospital were included in a pre-planned post-hoc analysis of two controlled intervention trials. Baseline assessment included history, clinical examination, radiography and measurements of procalcitonin (PCT), highly sensitive C-reactive protein (hsCRP) and leukocyte count. RESULTS: Of the 545 patients, 373 had CAP, 132 other respiratory tract infections, and 40 other final diagnoses. The AUC of a clinical model including standard clinical signs and symptoms (i.e. fever, cough, sputum production, abnormal chest auscultation and dyspnea) to diagnose CAP was 0.79 [95% CI, 0.75–0.83]. This AUC was significantly improved by including PCT and hsCRP (0.92 [0.89–0.94]; p < 0.001). PCT had a higher diagnostic accuracy (AUC, 0.88 [0.84–0.93]) in differentiating CAP from other diagnoses, as compared to hsCRP (AUC, 0.76 [0.69–0.83]; p < 0.001) and total leukocyte count (AUC, 0.69 [0.62–0.77]; p < 0.001). To predict bacteremia, PCT had a higher AUC (0.85 [0.80–0.91]) as compared to hsCRP (p = 0.01), leukocyte count (p = 0.002) and elevated body temperature (p < 0.001). PCT, in contrast to hsCRP and leukocyte count, increased with increasing severity of CAP, as assessed by the pneumonia severity index (p < 0.001). CONCLUSION: PCT, and to a lesser degree hsCRP, improve the accuracy of currently recommended approaches for the diagnosis of CAP, thereby complementing clinical signs and symptoms. PCT is useful in the severity assessment of CAP

Procalcitonin for diagnosis of infection and guide to antibiotic decisions: past, present and future

There are a number of limitations to using conventional diagnostic markers for patients with clinical suspicion of infection. As a consequence, unnecessary and prolonged exposure to antimicrobial agents adversely affect patient outcomes, while inappropriate antibiotic therapy increases antibiotic resistance. A growing body of evidence supports the use of procalcitonin (PCT) to improve diagnosis of bacterial infections and to guide antibiotic therapy. For patients with upper and lower respiratory tract infection, post-operative infections and for severe sepsis patients in the intensive care unit, randomized-controlled trials have shown a benefit of using PCT algorithms to guide decisions about initiation and/or discontinuation of antibiotic therapy. For some other types of infections, observational studies have shown promising first results, but further intervention studies are needed before use of PCT in clinical routine can be recommended. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and discuss the reliability of this marker when used with validated diagnostic algorithms

Prognostic effect of exercise capacity on mortality in older adults with diabetes mellitus

Objectives: To investigate the prognostic effect of exercise capacity in older individuals with diabetes mellitus. Design: Retrospective data review in a clinic-based cohort. Setting: Veterans Affairs Medical Centers in Washington, District of Columbia, and Palo Alto, California. Participants: Two thousand eight hundred sixty-seven men aged 50 to 87 with type 2 diabetes mellitus. Measurements: Exercise tolerance testing with fitness categories based on peak metabolic equivalents of task (METs) achieved adjusted for age. All-cause mortality in age groups 50 to 65 (Group 1; n=1,658) and older than 65 (Group 2; n=1,209) was analyzed using adjusted Cox proportional hazards models. Results: After a mean ± standard deviation follow-up period of 7.8 ± 5.1 years, there were 324 deaths in Group 1 (20%) and 464 in Group 2 (38%). For each 1-MET increase in exercise capacity, mortality was 18% lower for the entire cohort (hazard ratio (HR)=0.82, 95% confidence interval (CI)=0.79-0.86), 23% lower for Group 1 (HR=0.77, 95% CI=0.73-0.82), and 16% lower for Group 2 (HR=0.84, 95% CI=0.8-0.89). When fitness categories were considered, the mortality risk was 30% to 80% lower for those who achieved more than 4 METs in both age groups. Conclusion: Augmented exercise capacity is associated with lower risk of mortality in people with type 2 diabetes mellitus aged 50 to 65 as well as in those older than 65. Thus, physical fitness, as represented by exercise capacity, lowers mortality risk in people with diabetes mellitus irrespective of age. These findings suggest that healthcare providers should be cognizant of the level of exercise capacity in individual patients and encourage a physically active lifestyle regardless of age. © 2010 The American Geriatrics Society