OBJECTIVES: (1) To determine the value of emergency department chief complaint (CC) and International Classification of Disease diagnostic codes for identifying respiratory illness in a pediatric population and (2) to modify standard respiratory CC and diagnostic code sets to better identify respiratory illness in children. RESULTS: We determined the sensitivity and specificity of CC and diagnostic codes by comparing code groups with a criterion standard. CC and diagnostic codes for 500 pediatric emergency department patients were retrospectively classified as respiratory or nonrespiratory. Respiratory diagnostic codes were further classified as upper or lower respiratory. The criterion standard was a blinded, reviewer-assigned illness category based on history, physical examination, test results, and treatment. We also modified our respiratory code sets to better identify respiratory illness in this population. METHODS: Four hundred ninety-six charts met inclusion criteria. By the criterion standard, 87 (18%) patients had upper and 47 (10%) had lower respiratory illness. The specificity of CC and diagnostic codes groups was >0.97 [95% confidence interval (CI) 0.95-0.98]. The code group sensitivities were as follows: CC was 0.47 (95% CI 0.38-0.55), upper respiratory diagnostic was 0.56 (95% CI 0.45-0.67), lower respiratory diagnostic was 0.87 (95% CI 0.74-0.95), and combined CC and/or diagnostic was 0.72 (95% CI 0.63-0.79). Modifying the respiratory code sets to better identify respiratory illness increased sensitivity but decreased specificity. CONCLUSIONS: Diagnostic and CC codes have substantial value for emergency department syndromic surveillance. Adapting our respiratory code sets to a pediatric population forced a tradeoff between sensitivity and specificity.

CONTEXT: Limited computed tomography with rectal contrast (CTRC) has been shown to be 98% accurate in the diagnosis of appendicitis in the adult population, but data are lacking regarding the accuracy and effectiveness of this technique in diagnosing pediatric appendicitis. OBJECTIVE: To determine the diagnostic value of a protocol involving ultrasonography and CTRC in the diagnosis and management of appendicitis in children and adolescents. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study of 139 children and adolescents aged 3 to 21 years (2 patients were older than 18 years) who had equivocal clinical findings for acute appendicitis and who presented to the emergency department of a large, urban, pediatric teaching hospital between July and December 1998. Interventions Children were first evaluated with pelvic ultrasonography. If the result was definitive for appendicitis, laparotomy was performed; if ultrasonography was negative or inconclusive, CTRC was obtained. Patients who did not undergo laparotomy had telephone follow-up at 2 weeks and medical records of all patients were reviewed 4 to 6 months after study completion. MAIN OUTCOME MEASURES: Specificity, sensitivity, positive predictive value, negative predictive value, and accuracy of tests based on final diagnoses; surgeons' estimated likelihood of appendicitis on a scale of 1 to 10 for each case and their case management plans before imaging, after ultrasonography, and after CTRC. RESULTS: A total of 108 patients underwent both ultrasonography and CTRC examinations. The protocol had a sensitivity of 94%, specificity of 94%, positive predictive value of 90%, negative predictive value of 97%, and accuracy of 94%. A normal appendix was identified by ultrasonography in 2 (2.4%) of 83 patients without appendicitis and by CTRC in 62 (84%) of 74 patients. A negative ultrasonography result did not change the surgeons' clinical confidence level in excluding appendicitis (P= .06), while a negative CTRC result did have a significant effect (P.001). Positive results obtained for either ultrasonography or CTRC significantly affected surgeons' estimated likelihood of appendicitis (P=.001 and P.001, respectively). Ultrasonography resulted in a beneficial change in patient management in 26 (18.7%) of 139 children while CTRC correctly changed management in 79 (73.1%) of 108. CONCLUSIONS: These data show that CTRC following a negative or indeterminate ultrasonography result is highly accurate in the diagnosis of appendicitis in children.

BACKGROUND: Widespread availability of geographic information systems software has facilitated the use of disease mapping in academia, government and private sector. Maps that display the address of affected patients are often exchanged in public forums, and published in peer-reviewed journal articles. As previously reported, a search of figure legends in five major medical journals found 19 articles from 1994-2004 that identify over 19,000 patient addresses. In this report, a method is presented to evaluate whether patient privacy is being breached in the publication of low-resolution disease maps. RESULTS: To demonstrate the effect, a hypothetical low-resolution map of geocoded patient addresses was created and the accuracy with which patient addresses can be resolved is described. Through georeferencing and unsupervised classification of the original image, the method precisely re-identified 26% (144/550) of the patient addresses from a presentation quality map and 79% (432/550) from a publication quality map. For the presentation quality map, 99.8% of the addresses were within 70 meters (approximately one city block length) of the predicted patient location, 51.6% of addresses were identified within five buildings, 70.7% within ten buildings and 93% within twenty buildings. For the publication quality map, all addresses were within 14 meters and 11 buildings of the predicted patient location. CONCLUSION: This study demonstrates that lowering the resolution of a map displaying geocoded patient addresses does not sufficiently protect patient addresses from re-identification. Guidelines to protect patient privacy, including those of medical journals, should reflect policies that ensure privacy protection when spatial data are displayed or published.

Immediately following the Boston Marathon attacks, individuals near the scene posted a deluge of data to social media sites. Previous work has shown that these data can be leveraged to provide rapid insight during natural disasters, disease outbreaks and ongoing conflicts that can assist in the public health and medical response. Here, we examine and discuss the social media messages posted immediately after and around the Boston Marathon bombings, and find that specific keywords appear frequently prior to official public safety and news media reports. Individuals immediately adjacent to the explosions posted messages within minutes via Twitter which identify the location and specifics of events, demonstrating a role for social media in the early recognition and characterization of emergency events. *Christopher Cassa and Rumi Chunara contributed equally to this work.

OBJECTIVE: To determine the time to detection of positive blood, urine, and cerebrospinal fluid (CSF) cultures among febrile 28- to 90-day-old infants. STUDY DESIGN: Retrospective cohort of consecutive 28- to 90-day-old infants presenting with a temperature of >/=38 degrees C to an urban pediatric emergency department. Positive cultures and times to detection were noted. Patients were categorized as being at high risk for serious bacterial illness (SBI) based on clinical and laboratory criteria. RESULTS: Of the 3166 febrile infants seen in the emergency department during the study, 2733 had blood (86%), 2517 had urine (80%), and 2361 had CSF (75%) specimens obtained for culture, and 2190 had all 3 cultures (69%) sent. There were 224 positive cultures in 214 patients; of these, 191 had all 3 cultures (89%) sent. Subsequent analyses were confined to those who had all 3 cultures sent. The detected rate of SBI was 8.7% (191/2190). There were 28 positive blood cultures (1. 3%), 165 positive urine cultures (7.5%), and 8 positive CSF cultures (.4%). Median time to detection of positive cultures was 16 hours for blood, 16 hours for urine, and 18 hours for CSF. Four blood cultures (.1%), 20 urine cultures (.9%), and 0 CSF cultures were noted to have growth of a pathogen >24 hours after the specimen was obtained. All 4 blood cultures and 17 of 20 urine cultures with growth noted after 24 hours occurred among high-risk patients. CONCLUSIONS: The risk of identifying SBI after 24 hours is 1.1% among all 28- to 90-day-old febrile infants and.3% in low-risk infants.

BACKGROUND: Emergency department (ED) based syndromic surveillance systems identify abnormally high visit rates that may be an early signal of a bioterrorist attack. For example, an anthrax outbreak might first be detectable as an unusual increase in the number of patients reporting to the ED with respiratory symptoms. Reliably identifying these abnormal visit patterns requires a good understanding of the normal patterns of healthcare usage. Unfortunately, systematic methods for determining the expected number of (ED) visits on a particular day have not yet been well established. We present here a generalized methodology for developing models of expected ED visit rates. METHODS: Using time-series methods, we developed robust models of ED utilization for the purpose of defining expected visit rates. The models were based on nearly a decade of historical data at a major metropolitan academic, tertiary care pediatric emergency department. The historical data were fit using trimmed-mean seasonal models, and additional models were fit with autoregressive integrated moving average (ARIMA) residuals to account for recent trends in the data. The detection capabilities of the model were tested with simulated outbreaks. RESULTS: Models were built both for overall visits and for respiratory-related visits, classified according to the chief complaint recorded at the beginning of each visit. The mean absolute percentage error of the ARIMA models was 9.37% for overall visits and 27.54% for respiratory visits. A simple detection system based on the ARIMA model of overall visits was able to detect 7-day-long simulated outbreaks of 30 visits per day with 100% sensitivity and 97% specificity. Sensitivity decreased with outbreak size, dropping to 94% for outbreaks of 20 visits per day, and 57% for 10 visits per day, all while maintaining a 97% benchmark specificity. CONCLUSIONS: Time series methods applied to historical ED utilization data are an important tool for syndromic surveillance. Accurate forecasting of emergency department total utilization as well as the rates of particular syndromes is possible. The multiple models in the system account for both long-term and recent trends, and an integrated alarms strategy combining these two perspectives may provide a more complete picture to public health authorities. The systematic methodology described here can be generalized to other healthcare settings to develop automated surveillance systems capable of detecting anomalies in disease patterns and healthcare utilization.

BACKGROUND: COX-2 selective inhibitors are associated with myocardial infarction (MI). We sought to determine whether population health monitoring would have revealed the effect of COX-2 inhibitors on population-level patterns of MI. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a retrospective study of inpatients at two Boston hospitals, from January 1997 to March 2006. There was a population-level rise in the rate of MI that reached 52.0 MI-related hospitalizations per 100,000 (a two standard deviation exceedence) in January of 2000, eight months after the introduction of rofecoxib and one year after celecoxib. The exceedence vanished within one month of the withdrawal of rofecoxib. Trends in inpatient stay due to MI were tightly coupled to the rise and fall of prescriptions of COX-2 inhibitors, with an 18.5% increase in inpatient stays for MI when both rofecoxib and celecoxib were on the market (P0.001). For every million prescriptions of rofecoxib and celecoxib, there was a 0.5% increase in MI (95%CI 0.1 to 0.9) explaining 50.3% of the deviance in yearly variation of MI-related hospitalizations. There was a negative association between mean age at MI and volume of prescriptions for celecoxib and rofecoxib (Spearman correlation, -0.67, P0.05). CONCLUSIONS/SIGNIFICANCE: The strong relationship between prescribing and outcome time series supports a population-level impact of COX-2 inhibitors on MI incidence. Further, mean age at MI appears to have been lowered by use of these medications. Use of a population monitoring approach as an adjunct to pharmacovigilence methods might have helped confirm the suspected association, providing earlier support for the market withdrawal of rofecoxib.

This study aimed to comprehensively describe prevalence and temporal dispensing patterns for medications prescribed to children and adolescents in the United States. Participants were 1.6 million children (49% female) under 18 years old enrolled in a nation-wide, employer-provided insurance plan. All medication claims from 1999-2006 were reviewed retrospectively. Drugs were assigned to 16 broad therapeutic categories. Effects of trend over time, seasonality, age and gender on overall and within category prevalence were examined. RESULTS: Mean monthly prevalence for dispensed medications was 23.5% (range 19.4-27.5), with highest rates in winter and lowest in July. The age group with the highest prevalence was one-year-old children. On average each month, 17.1% of all children were dispensed a single drug and 6.4% were dispensed two or more. Over time, prevalence for two or more drugs did not change, but the proportion of children dispensed a single drug decreased (slope -.02%, p= .001). Overall, boys had higher monthly rates than girls (average difference 0.9%, p= .002). However, differences by gender were greatest during middle childhood, especially for respiratory and central nervous system agents. Contraceptives accounted for a large proportion of dispensed medication to older teenage girls. Rates for the drugs with the highest prevalence in this study were moderately correlated (average Pearson r.66) with those from a previously published national survey. CONCLUSION: On average, nearly one quarter of a population of insured children in the United States was dispensed medication each month. This rate decreased somewhat over time, primarily because proportionally fewer children were dispensed a single medication. The rate for two or more drugs dispensed simultaneously remained steady.