A Methodological Framework for the Evaluation of Syndromic Surveillance Systems: A Case Study of England

Background: Syndromic surveillance complements traditional public health surveillance by collecting and analysing health indicators in near real time. The rationale of syndromic surveillance is that it may detect health threats faster than traditional surveillance systems permitting more timely, and hence potentially more effective public health action. The effectiveness of syndromic surveillance largely relies on the methods used to detect aberrations. Very few studies have evaluated the performance of syndromic surveillance systems and consequently little is known about the types of events that such systems can and cannot detect. Methods: We introduce a framework for the evaluation of syndromic surveillance systems that can be used in any setting based upon the use of simulated scenarios. For a range of scenarios this allows the time and probability of to be determined and uncertainty is fully incorporated. In addition, we demonstrate how such a framework can model the benefits of increases in the number of centres reporting syndromic data and also determine the minimum size of outbreaks that can or cannot be detected. Here, we demonstrate its utility using simulations of national influenza outbreaks and localised outbreaks of cryptosporidiosis. Results: Influenza outbreaks are consistently detected with larger outbreaks being detected in a more timely manner. Small cryptosporidiosis outbreaks (<1000 symptomatic individuals) are unlikely to be detected. We also demonstrate the advantages of having multiple syndromic data streams (e.g. emergency attendance data, telephone helpline data, general practice consultation data) as different streams are able to detect different types outbreaks with different efficacy (e.g. emergency attendance data are useful for the detection of pandemic influenza but not for outbreaks of cryptosporidiosis). We also highlight that for any one disease, the utility of data streams may vary geographically, and that the detection ability of syndromic surveillance varies seasonally (e.g. an influenza outbreak starting in July is detected sooner than one starting later in the year). We argue that our framework constitutes a useful tool for public health emergency preparedness in multiple settings. Conclusions: The proposed framework allows the exhaustive evaluation of any syndromic surveillance system and constitutes a useful tool for emergency preparedness and response

Pretreatment quality of life and functional status assessment significantly predict survival of elderly patients with advanced non-small-cell lung cancer receiving chemotherapy: a prognostic analysis of the multicenter Italian lung cancer in the elderly study.

Purpose To study the prognostic value for overall survival of baseline assessment of functional status, comorbidity, and quality of life (QoL) in elderly patients with advanced non–small-cell lung cancer treated with chemotherapy. Patients and Methods Data from 566 patients enrolled onto the phase III randomized Multicenter Italian Lung Cancer in the Elderly Study (MILES) study were analyzed. Functional status was measured as activities of daily living (ADL) and instrumental ADL (IADL). The presence of comorbidity was assessed with a checklist of 33 items; items 29 and 30 of the European Organisation for Research and Treatment of Cancer (EORTC) core questionnaire QLQ-C30 (EORTC QLQ-C30) were used to estimate QoL. ADL was dichotomized as none versus one or more dependency. For IADL and QoL, three categories were defined using first and third quartiles as cut points. Comorbidity was summarized using the Charlson scale. Analysis was performed by Cox model, and stratified by treatment arm. Results Better values of baseline QoL (P .0003) and IADL (P .04) were significantly associated with better prognosis, whereas ADL (P .44) and Charlson score (P .66) had no prognostic value. Performance status 2 (P .006) and a higher number of metastatic sites (P .02) also predicted shorter overall survival. Conclusions Pretreatment global QoL and IADL scores, but not ADL and comorbidity, have significant prognostic value for survival of elderly patients with advanced non–small-cell lung cancer who were treated with chemotherapy. Using these scores in clinical practice might improve prognostic prediction for treatment planning