STUDY OBJECTIVE:s: To develop and validate a patient-based outcome measure to evaluate symptoms in patients with community-acquired pneumonia (CAP). DESIGN: A psychometric study within an international, prospective, randomized, double-blind study. The CAP-symptom questionnaire (CAP-Sym) is a new, 18-item, patient-reported outcome measure that evaluates the bothersomeness of CAP-related symptoms during the past 24 h using a 6-point Likert scale. We used "gold standard" psychometric methods to comprehensively evaluate the acceptability, reliability, validity, and responsiveness of the CAP-Sym. SETTING: Sixty-four centers in 13 countries (France, Germany, Hungary, Israel, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, United Kingdom). PATIENTS: Five hundred fifty-six patients with CAP, recruited from outpatient clinics, general practice, and hospital centers. INTERVENTIONS: Randomization 1:1 to moxifloxacin (400 mg once daily), oral or standard oral treatment (amoxicillin, 1 g tid, or clarithromycin, 500 mg bid), alone or in combination, for up to 14 days. RESULTS: Standard psychometric tests confirmed the acceptability (item nonresponse, item-endorsement frequencies, item/scale floor and ceiling effects), reliability (internal consistency, item-total and inter-item correlations, test-retest reliability), validity (content, construct, convergent, discriminant, known groups), and responsiveness of the CAP-Sym. CONCLUSIONS: The CAP-Sym is a practical and scientifically sound patient-based outcome measure of CAP-related symptoms that has been developed using "gold standard" methods. As the only fully validated measure of symptoms in patients with CAP, which is quick and easy to administer and is more responsive than the generic Medical Outcomes Study 36-Item Short-Form Health Survey, the CAP-Sym provides a practical and rigorous method for improving the evaluation of outcomes in clinical trials and audit.
The goal of this paper is to analyse the scaling properties of childhood infectious disease time-series data. We present a scaling analysis of the distribution of epidemic sizes of measles, rubella, pertussis, and mumps outbreaks in Canada. This application provides a new approach in assessing infectious disease dynamics in a large vaccinated population. An inverse power-law (IPL) distribution function has been fit to the time series of epidemic sizes, and the results assessed against an exponential benchmark model. We have found that the rubella epidemic size distribution and that of measles in highly vaccinated periods follow an IPL. The IPL suggests the presence of a scale-invariant network for these diseases as a result of the heterogeneity of the individual contact rates. By contrast, it was found that pertussis and mumps were characterized by a uniform network of transmission of the exponential type, which suggests homogeneity in the contact rate or, more likely, boiled down heterogeneity by large intermixing in the population. We conclude that the topology of the network of infectious contacts depends on the disease type and its infection rate. It also appears that the socio-demographic structure of the population may play a part (e.g. pattern of contacts according to age) in the structuring of the topology of the network. The findings suggest that there is relevant information hidden in the variation of the common contagious disease time-series data, and that this information can have a bearing on the strategy of vaccination programs.