Evaluation of a web-based tool for labelling potential hospital outbreaks: a mixed methods study.

BACKGROUND: Labelling outbreaks in surveillance data is necessary to train advanced analytical methods for outbreak detection, but there is a lack of software tools dedicated to this task. AIM: To evaluate the usability of a web-based tool by infection control practitioners for labelling potential outbreaks. METHODS: A mixed methods design was used to evaluate how 25 experts from France and Canada interacted with a web-based application to identify potential outbreaks. Each expert used the application to retrospectively review 11-12 1-year incidence time series from 23 different types of micro-organism. The interactions between the users and the application were recorded and analysed using mixed effect models. The users' comments were analysed via qualitative methods. FINDINGS: From the 240 reviews completed, 439 potential outbreaks were labelled, approximately half with a high probability. Significant heterogeneity was observed between users regarding their answers and behaviours (evaluation time, usage of the different options). A significant learning effect was also observed for the experts' interactions with the tool, but this did not seem to impact their answers. The content analysis of the comments highlighted the difficulty of early outbreak identification for practitioners, but also the potential utility of web applications such as that evaluated for routine surveillance. CONCLUSION: The interactive web application was both usable and useful for infection control practitioners. Its implementation in routine practice could help professionals to identify potential outbreaks while creating data to train automated detection algorithms.

An exploratory analysis of individuals with multiple episodes of different reportable diseases, Montreal, 1990-2012.

OBJECTIVES: Studies of public health reporting have only examined multiple episodes of the same communicable disease within an individual. We aimed to characterize Montreal residents with multiple reportable disease episodes from 1990 to 2012, while accounting for all types of reportable diseases. STUDY DESIGN: Retrospective cohort study. METHODS: We performed an exploratory analysis using descriptive statistics, contingency tables, and logistic regression. RESULTS: There were 157,839 individuals with at least one disease report and a total of 179,455 disease reports. The 9.8% of subjects with more than one episode accounted for 20.7% of all reported episodes. Among subjects with four or fewer episodes, 54.0% were women, while 74.3% of subjects with five or more episodes were men. Subjects with multiple episodes were more likely to be reported for sexually transmitted infections than were persons with a single episode [difference of proportions: 10.4% (95% CI: 10.0%-10.9%)] and to reside in the neighbourhood encompassing Montreal's gay village. CONCLUSIONS: Individuals with multiple communicable disease reports place a large burden on public health officials. These results may help guide investigation and prevention efforts to reduce the number of excess episodes.

The accuracy and timeliness of neuraminidase inhibitor dispensing data for predicting laboratory-confirmed influenza.

Neuraminidase inhibitor (NI) dispensing has emerged as a possible automated data source for influenza surveillance. We aimed to evaluate its timeliness, correlation, and predictive accuracy in relation to influenza activity in Quebec, Canada, 2010-2013. Our secondary objective was to use the same metrics to compare NI dispensing to visits for influenza-like illness (ILI) in emergency departments (EDs). Provincial weekly counts of positive influenza laboratory tests were used as a reference measure for the level of influenza circulation. We applied ARIMA models to account for serial correlation. We computed cross-correlations to measure the strengths of association and lead-lag relationships between NI dispensing, ILI ED visits, and our reference indicator. Finally, using an ARIMA model, we evaluated the ability of NI dispensing and ILI ED visits to predict laboratory-confirmed influenza. NI dispensing was significantly correlated (R = 0·68) with influenza activity with no lag. The maximal correlation of ILI ED visits was not as strong (R = 0·50). Both NI dispensing and ILI ED visits were significant predictors of laboratory-confirmed influenza in a multivariable model; predictive potential was greatest when NI counts were lagged to precede laboratory surveillance by 2 weeks. We conclude that NI dispensing data provides timely and valuable information for influenza surveillance.

Measuring antimicrobial use in hospitalized patients: a systematic review of available measures applicable to paediatrics.

OBJECTIVES: The optimal measure to use for surveillance of antimicrobial usage in hospital settings, especially when including paediatric populations, is unknown. This systematic review of literature aims to list, define and compare existing measures of antimicrobial use that have been applied in settings that included paediatric inpatients, to complement surveillance of resistance. METHODS: We identified cohort studies and repeated point-prevalence studies presenting data on antimicrobial use in populations of inpatients or validations/comparisons of antimicrobial measures through a systematic search of literature using MEDLINE, EMBASE, CINAHL and LILACS (1975-2011) and citation tracking. Study populations needed to include hospitalized paediatric patients. Two reviewers independently extracted data on study characteristics and results. RESULTS: Overall, 3878 records were screened and 79 studies met selection criteria. Twenty-six distinct measures were found, the most frequently used being defined daily doses (DDD)/patient-days and exposed patients/patients. Only two studies compared different measures quantitatively, showing (i) a positive correlation between proportion of exposed patients and antimicrobial-days/patient-days and (ii) a strong correlation between doses/patient-days and agent-days/patient-days (r = 0.98), with doses/patient-days correlating more with resistance rates (r = 0.80 versus 0.55). CONCLUSIONS: The measure of antimicrobial use that best predicts antimicrobial resistance prevalence and rates, for surveillance purposes, has still not been identified; additional evidence on this topic is a necessity.

Increased influenza-related healthcare utilization by residents of an urban aboriginal community.

Most studies describing high rates of acute respiratory illness in aboriginals have focused on rural or remote communities. Hypothesized causes include socioeconomic deprivation, limited access to healthcare, and a high prevalence of chronic disease. To assess influenza rates in an aboriginal community while accounting for healthcare access, deprivation and chronic disease prevalence, we compared rates of influenza-related outpatient and emergency-department visits in an urban Mohawk reserve (Kahnawá:ke) to rates in neighbouring regions with comparable living conditions and then restricted the analysis to a sub-population with a low chronic disease prevalence, i.e. those aged <20 years. Using medical billing claims from 1996 to 2006 we estimated age-sex standardized rate ratios. The rate in Kahnawá:ke was 58% greater than neighbouring regions and 98% greater in the analysis of those aged <20 years. Despite relatively favourable socioeconomic conditions and healthcare access, rates of influenza-related visits in Kahnawá:ke were elevated, particularly in the younger age groups.

Effect of environmental factors on the spatio-temporal patterns of influenza spread.

Although spatio-temporal patterns of influenza spread often suggest that environmental factors play a role, their effect on the geographical variation in the timing of annual epidemics has not been assessed. We examined the effect of solar radiation, dew point, temperature and geographical position on the city-specific timing of epidemics in the USA. Using paediatric in-patient data from hospitals in 35 cities for each influenza season in the study period 2000-2005, we determined 'epidemic timing' by identifying the week of peak influenza activity. For each city we calculated averages of daily climate measurements for 1 October to 31 December. Bayesian hierarchical models were used to assess the strength of association between each variable and epidemic timing. Of the climate variables only solar radiation was significantly related to epidemic timing (95% CI -0.027 to -0.0032). Future studies may elucidate biological mechanisms intrinsically linked to solar radiation that contribute to epidemic timing in temperate regions.

Health informatics education: an opportunity for public health in Canada.

Health information infrastructure is being developed across Canada, and health informatics education should be a component of the emerging infrastructure. However, educational opportunities do not appear to be developing in pace with infrastructure. This study characterizes the required education, and describes specific issues facing the development of health informatics education. Twenty-six key informants were interviewed, and responses were analyzed to identify major themes. Subjects agreed that the current capacity for health informatics education is inadequate. Also, limited expertise could adversely affect health infostructure implementation and health system performance. A need was identified for both advanced and basic education. Four issues facing the development of health informatics education in Canada were consistently identified: awareness, collaboration, funding, and human resources. Public health is well positioned to play a central role in health informatics education due to its historical basis in handling health information, and its developing expertise in health informatics applications.

Efficacy of immunotherapy to ragweed antigen tested by controlled antigen exposure.

BACKGROUND: Immunotherapy is a recognized component in the management of allergic rhinitis. Its efficacy has been evaluated in a number of clinical field trials. These methods of evaluation are limited by control of antigen exposure. OBJECTIVE: A study was designed to evaluate the efficacy of immunotherapy in ragweed-induced rhinoconjunctivitis using an environmental exposure unit. METHODS: Forty-three subjects were grouped into (1) immunotherapy group: ragweed-allergic subjects on maintenance ragweed immunotherapy for at least 2 years (N = 16), (2) positive control group: ragweed-allergic subjects who had never received immunotherapy (n = 16), and (3) negative control group: ragweed-nonallergic subjects (N = 11). Ragweed specific skin tests and ragweed IgE levels were obtained prior to exposure. The study was done in a room where levels of 2,500 to 3,000 grains m3 of ragweed were maintained over three hours. Symptoms were recorded every 15 minutes. RESULTS: Nasal symptoms in the immunotherapy group were significantly less than in the positive control group after 45 minutes (P = .025). Significant differences were not observed for ocular symptoms. Combined nasal and ocular scores were 50% less in the immunotherapy group than in the positive control group by 75 minutes (P = .039). Ragweed-specific skin tests and IgE were significantly less in the immunotherapy group than in the positive control group. Rhinoconjunctivitis symptoms in the negative control group were absent throughout. CONCLUSIONS: Controlled ragweed pollen exposure in this setting demonstrated that ragweed immunotherapy significantly reduced symptoms of ragweed-allergic rhinitis but had no significant effect on ocular symptoms. This system presents opportunities for additional studies on immunotherapy for allergic respiratory conditions.

A randomized, double-blind, placebo-controlled, controlled antigen delivery study of the onset of action of aerosolized triamcinolone acetonide nasal spray in subjects with ragweed-induced allergic rhinitis.

BACKGROUND: Clinically apparent relief of nasal symptoms of allergic rhinitis is generally recognized to occur within 3 days to 1 week when intranasal corticosteroids are used. OBJECTIVE: A study was designed to evaluate the onset of action of triamcinolone acetonide (TA) in patients with ragweed-induced allergic rhinitis with an environmental exposure unit (EEU). METHODS: Eighty-five adults with ragweed-induced allergic rhinitis were primed with ragweed allergen in the EEU. Symptoms were recorded during a baseline exposure in the EEU, and subjects were randomized with a 5:1 ratio to receive either TA 400 micrograms (n = 71) or its propellant (n = 14). Subjects received study medication for 7 days under supervision in the morning and returned to the EEU in the evening for ragweed allergen challenge and symptom assessment. Clinically apparent onset of action was defined as a 25% decrease in symptom scores from baseline. RESULTS: A mean reduction in nasal congestion from baseline of greater than 25% (onset of action) was observed in the TA group, but not in the placebo group, by 10 hours. This was also observed for itching of the nose or palate and a combined measure of symptoms. In addition, the proportion of subjects with less nasal congestion after 1 day of treatment was greater in the TA group (41%) than in the placebo group (7%) (p less than 0.05). CONCLUSION: The unexpected early relief of symptoms observed in the TA group and, to a lesser extent in the placebo group, has important clinical implications in the treatment of allergic rhinitis.

Risk assessment in determining systemic reactivity to honeybee stings in sting-threatened individuals.

We evaluated the diagnostic parameters (sting rate, venom-specific RAST IgE, venom-specific RAST IgG, venom-specific IgG4, venom-specific skin test) of 224 individuals at risk of honeybee sting, assigned them a level of risk on the basis of a hypothetical risk model, and then sting challenged each subject with a live honeybee. Of the 70 subjects at the lowest risk level, only three (4.3%) experienced equivocal or mild systemic reactions, whereas eight (72.7%) of the 11 at the highest risk level experienced systemic reactions, of which five (45.5%) were severe. Increase in risk level was associated with an increased proportion of systemic reactions (p < 0.001). Of the individual diagnostic parameters, venom-specific RAST IgE was the best single predictor of reactivity (likelihood ratio = 0.759, p < 0.01). Venom-specific skin testing at a concentration of 0.1 microgram/ml was a better discriminator than a concentration of 1.0 microgram/ml but did not predict one severe systemic reaction. Three methods of prediction of risk and severity of reaction were examined; the one that assessed risk in the most clinically useful manner was similar to the hypothetical risk model. This model compared well with classical methods of risk assessment and may be used to assess high-risk individuals exposed to honeybees when management could include prophylactic immunotherapy.