Sylvain Roche

Risk of Influenza-Like Illness in an Acute Health Care Setting During Community Influenza Epidemics in 2004-2005, 2005-2006, and 2006-2007: A Prospective Study

BACKGROUND The person-to-person transmission of influenza-like illness (ILI) and influenza has been described mostly in long-term care units. Studies in acute hospital settings are rare and mostly retrospective. METHODS We prospectively estimated the relative risk (RR) of hospital-acquired (HA) ILI during hospitalization according to in-hospital exposures to contagious individuals. Surveillance of ILI and laboratory-confirmed influenza was undertaken at Edouard Herriot Hospital (1100 beds) during 3 influenza seasons. A total of 21 519 patients and 2153 health care workers (HCWs) from 2004 to 2007 were included. The RR of HA-ILI in patients was calculated according to exposure to other contagious patients and HCWs. RESULTS For patients exposed to at least 1 contagious HCW compared with those with no documented exposure in the hospital, the RR of HA-ILI was 5.48 (95% confidence interval [CI], 2.09-14.37); for patients exposed to at least 1 contagious patient, the RR was 17.96 (95% CI, 10.07-32.03); and for patients exposed to at least 1 contagious patient and 1 contagious HCW, the RR was 34.75 (95% CI, 17.70-68.25). CONCLUSIONS Hospitalized patients exposed to potentially infectious patients and HCWs with ILI inside the hospital are at greater risk for HA-ILI. Such results identify priorities regarding preventive measures for seasonal or pandemic influenza.

Influence of oxidative stress biomarkers on cognitive decline.

BACKGROUND Abnormal oxidative stress is an established feature of Alzheimers disease (AD). Markers of lipoperoxidation and deficits in serum antioxidants could have a predictive value for identifying subjects at risk of dementia and to predict cognitive decline. OBJECTIVE Search for relationships between the levels of some oxidative stress biomarkers and cognitive function decline that would help predict this decline. METHODS The study solicited and included 97 patients aged 63 to 93 years with various suspected neurodegenerative diseases (35 with AD). They were followed up at six-month intervals over two years (2010-2012). The study: i) assessed the blood levels of glutathione peroxidase, glutathione, and malondialdehyde; ii) performed the Mini-Mental Status Examination (MMSE), the Clock Drawing test, the free/cued recall task with 16-item lists, the cue percentage; and the Trail Making Test; and iii) acquired brain magnetic resonance imaging or tomodensitometry. The primary outcome measure was the MMSE score. RESULTS The MMSE score was correlated with the score of each neuropsychological test, the age at baseline, and the glutathione level. On average, the decline in the MMSE score was 1.63 points per six months. A 100 International Unit increase in glutathione peroxidase was associated with an average loss of 1.19 MMSE points per six months (p = 0.002). A 100 μmol/L increase in glutathione was associated with an average loss of 1.80 MMSE points per six months (p = 0.014). CONCLUSION Oxidative stress biomarkers, especially glutathione peroxidase and glutathione, may predict the course of cognitive decline in patients with AD or other neurodegenerative disorders.

Methodology of the sensitivity analysis used for modeling an infectious disease

Mathematical models may be used to help clarify dynamics of several infectious diseases. Because of the complexity of some models and the high degree of uncertainty in estimating many parameters, the present study proposes a rigorous framework for sensitivity analyses of mathematical models using as example a model to assess varicella and herpes zoster incidence. Its main steps are to assess the uncertainty of the factors to be studied, to evaluate qualitatively and quantitatively the impacts of these factors on model results, and to conduct an univariate and multivariate sensitivity analysis. The application of this technique may have considerable utility in the analysis of a wide variety of complex biological and epidemiological models.

Validation of the French Version of Conners' Parent Rating Scale Revised, Short Version: Factorial Structure and Reliability.

Objective: Attention-deficit hyperactivity disorder is one of the most frequent neurodevelopmental disorders. Its diagnosis requires reference questionnaires such as the Conners’ Parent Rating Scale (CPRS). Presently, in French-speaking countries, a few translations of the revised short CPRS have been put to use without previous formal validation. We sought here for the validation of a French version (Lausanne, Switzerland) of the revised short CPRS regarding construct validity, internal consistency, and item reliability in a sample of French schoolchildren. Method: The study involved 795 children and adolescents aged 9 to 19 years from a single school. The factorial structure and item reliability were assessed with a confirmatory factor analysis for ordered categorical variables. The dimension internal consistency was assessed with Guttman’s lambda 6 coefficient. Results: The results confirmed the original and strong 3-dimensional factorial structure (Oppositional, Cognitive Problems/Inattention, and Hyperactivity), showed satisfactory item reliability, and indicated a good dimension internal consistency (Guttman’s lambda 6 coefficient: 0.87, 0.90, and 0.82, respectively, to the 3 dimensions). Conclusions: Thus, the Lausanne French version of the revised short CPRS may be considered validated regarding construct validity and item and dimension reliability; it can be now more confidently used in clinical practice.

Detection of hospital outbreaks of influenza-like illness based on excess of incidence rates compared to the community

The risk of nosocomial influenza-like illness (noso-ILI) compared with that of community-acquired ILI was calculated during 3 influenza seasons (2004-2007) at a 1100-bed university hospital with a total of 21,519 hospitalized patients. Outbreaks of noso-ILI occurred in each season, although a protective effect against noso-ILI was also identified for other wards.

Modeling and predicting the long-term effects of various strategies and objectives of varicella-zoster vaccination campaigns.

ABSTRACT Background: Susceptible, exposed, infected, and recovered (SEIR) models are increasingly developed and used, but their simplicity contrasts with the wide variety of scenarios before launching vaccination campaigns. Methods: We investigated the effects of some model-building choices (targets, pace, coverage rate) on the results of SEIR models in the case of vaccination against varicella and herpes zoster. Results: The analysis demonstrated the need for a progressive unvaccinated to vaccinated transition and a dynamic system-equilibrium before vaccination onset. When several doses are considered, new compartments are needed to account for vaccination histories. For varicella, the delay to reach the expected coverage rate and the pace until reaching this rate have significant impacts, especially on the short-term incidence. The impact of vaccination through herd immunity should be systematically investigated. Conclusions: Graphs help understanding the progress of instantaneous incidence; however, tables of cumulative average incidence over decades should be preferred because of higher stability.

A multiplicative hazard regression model to assess the risk of disease transmission at hospital during community epidemics.

BackgroundDuring community epidemics, infections may be imported within hospital and transmitted to hospitalized patients. Hospital outbreaks of communicable diseases have been increasingly reported during the last decades and have had significant consequences in terms of patient morbidity, mortality, and associated costs. Quantitative studies are thus needed to estimate the risks of communicable diseases among hospital patients, taking into account the epidemiological process outside, hospital and host-related risk factors of infection and the role of other patients and healthcare workers as sources of infection.MethodsWe propose a multiplicative hazard regression model to analyze the risk of acquiring a communicable disease by patients at hospital. This model derives from epidemiological data on communicable disease epidemics in the community, hospital ward, patient susceptibility to infection, and exposure of patients to infection at hospital. The model estimates the relative effect of each of these factors on a patients risk of communicable disease.ResultsUsing individual data on patients and health care workers in a teaching hospital during the 2004-2005 influenza season in Lyon (France), we show the ability of the model to assess the risk of influenza-like illness among hospitalized patients. The significant effects on the risk of influenza-like illness were those of old age, exposure to infectious patients or health care workers, and a stay in a medical care unit.ConclusionsThe proposed multiplicative hazard regression model could be an interesting epidemiological tool to quantify the risk of communicable disease at hospital during community epidemics and the uncertainty inherent in such quantification. Furthermore, key epidemiological, environmental, host, or exposure factors that influence this risk can be identified.

Glucose trajectories in cystic fibrosis and their association with pulmonary function

BACKGROUND The prevalence of cystic fibrosis-related diabetes is increasing. This condition is potentially responsible for respiratory decline. METHODS At inclusion, then yearly (over three years), 111 children and 117 adults with cystic fibrosis had oral glucose tolerance and insulin tests at one (G1) and 2h (G2). KmL analysis identified homogeneous G1 and G2 glucose trajectories. A linear mixed model quantified the relationships between trajectories and FEV1 changes. RESULTS In children, there were three G1 and four G2 trajectories and FEV1 decrease was not significantly different between G1 or G2 trajectories. In adults, two G1 and four G2 trajectories were identified and FEV1 change was estimated at -0.85/year (95% CI: [-1.54; -0.17], p=0.01) whatever the G1 trajectory and found significantly faster in the high and increasing G2 trajectory (-2.1/year, [-3.9; -0.2], p=0.03). CONCLUSIONS In case of persistent G2 abnormality, physicians should be alert for clinical deterioration and intensify patient surveillance.

Validation of the French Version of Conners’ Parent Rating Scale–Revised, Short Version (CPRS-R:S): Scale Measurement Invariance by Sex and Age

Objective: ADHD is one of the most frequent neurodevelopmental disorders. In addition to clinical assessment, its diagnosis requires the use of validated and reliable behavior questionnaires such as the Conners’ Parent Rating Scale–Revised: Short Form (CPRS-R:S). Though various French versions of the CPRS-R:S have been already put to use in clinical practice and research, only a few have undergone a stringent validation process. After a previous validation of the factorial structure of Lausanne French version, we sought here for the analysis of its invariance across sex and age. Method: This validation step was carried out in a rather homogeneous French population of 365 boys and 374 girls from a single school. Two-age classes were considered: children (boys and girls) aged 9 to 11 years (n = 258) and adolescents aged 12 to 15 years (n = 481). Results: Regarding age, dimension Oppositional showed a strong invariance whereas dimensions Hyperactivity and Cognitive problems/Inattention showed a partially strong invariance. Regarding sex, dimensions Oppositional and Hyperactivity showed a partially strong invariance whereas dimension Cognitive problems/Inattention showed a partially weak invariance. The distribution of the CPRS-R:S scores is given by sex and age class. Conclusion: The Lausanne French version of the CPRS-R:S, already validated regarding its factorial structure, internal consistency, and reliability, is here validated regarding its invariance across sex and age. Caution should be taken in using dimension Cognitive problems/Inattention in comparisons between boys and girls.

Validation of the French Version of Conners’ Parent Rating Scale–Revised, Short Form in ADHD-Diagnosed Children and Comparison With Control Children

Objective: The objective of this study was to examine measurement invariance and discriminant validity of the French Lausanne version (FLV) of the Conners’ Parent Rating Scale–Revised, Short Form (CPRS-R:S) and assess its convergent validity against the ADHD Symptoms Rating Scale (ADHD-SRS) and the Child Behavior Checklist (CBCL). Method: A confirmatory factor analysis and Tobit models were used in 108 ADHD children (aged 6-17) vs. 794 controls (aged 9-15) and score correlations were examined between FLV and ADHD-SRS then CBCL. Results: The factorial structure and reliability of the FLV is confirmed in ADHD children. The FLV showed configural invariance, metric invariance, and scalar invariance. FLV scores were significantly higher in ADHD than in control children in all three dimensions (p < .001). There were strong correlations between FLV Hyperactivity and Cognitive problems/Inattention scores and ADHD-SRS scores of Impulsivity/Hyperactivity (r = .90) and Inattention (r = .68) and also strong correlations between FLV Opposition score and the CBCL scores of Aggressive behavior (r = .84) and Rule-breaking behavior (r = .66). Conclusion: The study brings support for validation of the FLV regarding invariance in ADHD children, discriminant validity, and convergent validity.