Visual acuity measures do not reliably detect childhood refractive error - an epidemiological study

Purpose To investigate the utility of uncorrected visual acuity measures in screening for refractive error in white school children aged 6-7-years and 12-13-years. Methods The Northern Ireland Childhood Errors of Refraction (NICER) study used a stratified random cluster design to recruit children from schools in Northern Ireland. Detailed eye examinations included assessment of logMAR visual acuity and cycloplegic autorefraction. Spherical equivalent refractive data from the right eye were used to classify significant refractive error as myopia of at least 1DS, hyperopia as greater than +3.50DS and astigmatism as greater than 1.50DC, whether it occurred in isolation or in association with myopia or hyperopia. Results Results are presented from 661 white 12-13-year-old and 392 white 6-7-year-old school-children. Using a cut-off of uncorrected visual acuity poorer than 0.20 logMAR to detect significant refractive error gave a sensitivity of 50% and specificity of 92% in 6-7-year-olds and 73% and 93% respectively in 12-13-year-olds. In 12-13-year-old children a cut-off of poorer than 0.20 logMAR had a sensitivity of 92% and a specificity of 91% in detecting myopia and a sensitivity of 41% and a specificity of 84% in detecting hyperopia. Conclusions Vision screening using logMAR acuity can reliably detect myopia, but not hyperopia or astigmatism in school-age children. Providers of vision screening programs should be cognisant that where detection of uncorrected hyperopic and/or astigmatic refractive error is an aspiration, current UK protocols will not effectively deliver.

Dizziness in 10 year old children:an epidemiological study

OBJECTIVE: Current data about the prevalence and characteristics of dizziness in the paediatric population is very limited and the generalisability of extant studies to the UK population has not been explored. Our study aims to provide a robust estimate of the prevalence of dizziness in 10 year old children in the UK, to describe the characteristics of this dizziness and to explore whether this dizziness is socially patterned. METHODS: Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) was analysed (N=13,988). A total of 6965 of these children attended for a balance assessment session at age 10. Those who reported rotary vertigo were interviewed about their symptoms. Logistic regression was used to explore whether dizziness at age 10 is socially patterned. RESULTS: A total of 400 children reported rotary vertigo, giving a prevalence estimate of 5.7% [CI 5.2, 6.3%]. 13.1-20.6% of children reported experiencing their dizziness between 1 and 4 times a week (depending on the symptom). 51.5% of children had to stop what they were doing because of the dizziness making them feel unwell. A total of 60% of children reported headache as an accompanying symptom, tentatively suggesting a diagnosis of migraine, although there was no association between reports of headache and a maternal family history of migraine. 20.3% of children with dizziness also reported tinnitus and 17.3% reported that their hearing changed when they were dizzy. CONCLUSIONS: Dizziness in 10 year old children is not uncommon and in about half limits current activities. Rotary vertigo is commonly accompanied by dizziness of another description and also by headache. There is no evidence that dizziness at this age is socially patterned.

Description and critical appraisal of principal components analysis (PCA) methodology applied to pulsed-field gel electrophoresis profiles of methicillin-resistant Staphylococcus aureus isolates

Principal components analysis (PCA) has been described for over 50 years; however, it is rarely applied to the analysis of epidemiological data. In this study PCA was critically appraised in its ability to reveal relationships between pulsed-field gel electrophoresis (PFGE) profiles of methicillin- resistant Staphylococcus aureus (MRSA) in comparison to the more commonly employed cluster analysis and representation by dendrograms. The PFGE type following SmaI chromosomal digest was determined for 44 multidrug-resistant hospital-acquired methicillin-resistant S. aureus (MR-HA-MRSA) isolates, two multidrug-resistant community-acquired MRSA (MR-CA-MRSA), 50 hospital-acquired MRSA (HA-MRSA) isolates (from the University Hospital Birmingham, NHS Trust, UK) and 34 community-acquired MRSA (CA-MRSA) isolates (from general practitioners in Birmingham, UK). Strain relatedness was determined using Dice band-matching with UPGMA clustering and PCA. The results indicated that PCA revealed relationships between MRSA strains, which were more strongly correlated with known epidemiology, most likely because, unlike cluster analysis, PCA does not have the constraint of generating a hierarchic classification. In addition, PCA provides the opportunity for further analysis to identify key polymorphic bands within complex genotypic profiles, which is not always possible with dendrograms. Here we provide a detailed description of a PCA method for the analysis of PFGE profiles to complement further the epidemiological study of infectious disease. © 2005 Elsevier B.V. All rights reserved.

Spatially clustered associations in health GIS

Overlaying maps using a desktop GIS is often the first step of a multivariate spatial analysis. The potential of this operation has increased considerably as data sources and Web services to manipulate them are becoming widely available via the Internet. Standards from the OGC enable such geospatial mashups to be seamless and user driven, involving discovery of thematic data. The user is naturally inclined to look for spatial clusters and correlation of outcomes. Using classical cluster detection scan methods to identify multivariate associations can be problematic in this context, because of a lack of control on or knowledge about background populations. For public health and epidemiological mapping, this limiting factor can be critical but often the focus is on spatial identification of risk factors associated with health or clinical status. Spatial entropy index HSu for the ScankOO analysis of the hypothetical dataset using a vicinity which is fixed by the number of points without distinction between their labels. (The size of the labels is proportional to the inverse of the index) In this article we point out that this association itself can ensure some control on underlying populations, and develop an exploratory scan statistic framework for multivariate associations. Inference using statistical map methodologies can be used to test the clustered associations. The approach is illustrated with a hypothetical data example and an epidemiological study on community MRSA. Scenarios of potential use for online mashups are introduced but full implementation is left for further research.

Spatially clustered associations in health related geospatial data

Overlaying maps using a desktop GIS is often the first step of a multivariate spatial analysis. The potential of this operation has increased considerably as data sources an dWeb services to manipulate them are becoming widely available via the Internet. Standards from the OGC enable such geospatial ‘mashups’ to be seamless and user driven, involving discovery of thematic data. The user is naturally inclined to look for spatial clusters and ‘correlation’ of outcomes. Using classical cluster detection scan methods to identify multivariate associations can be problematic in this context, because of a lack of control on or knowledge about background populations. For public health and epidemiological mapping, this limiting factor can be critical but often the focus is on spatial identification of risk factors associated with health or clinical status. In this article we point out that this association itself can ensure some control on underlying populations, and develop an exploratory scan statistic framework for multivariate associations. Inference using statistical map methodologies can be used to test the clustered associations. The approach is illustrated with a hypothetical data example and an epidemiological study on community MRSA. Scenarios of potential use for online mashups are introduced but full implementation is left for further research.

Epidemiology of medication discrepancies upon hospital admission in children - a systematic review

Objectives: NICE/NPSA excluded children under 16 from their guidance concerning medicines reconciliation (MR) upon admission.1 Our aims and objectives of conducting the literature review was to identify the epidemiology of medication discrepancies upon admission, transfer and discharge in children, and if they require MR. Method: Six bibliographical databases (Medline, Embase, CINAHL, International Pharmaceutical Abstracts, Web of Science and Biosis Previews) and selected key words were used to find epidemiological studies on medication discrepancies in children upon hospital admission, transfer and discharge (key words included ‘medication discrepancy’; ‘medication reconciliation’; ‘hospital admission’; ‘hospital discharge’; ‘hospital transfer’); studies where the data for children could be extracted were included. Results: From the 1239 articles found (in May 2011), eight of the articles had extractable paediatric information, (five from Canada, two from USA, one from UK). Five of the studies involved discrepancies on admission, one involved discrepancies on admission and transfer, one involved discrepancies at transfer and one considered discharge. The reference point used to compare against the admission, transfer and the discharge order differed in each of the studies. Four studies used a rating scale to assess the clinical significance of the discrepancies to demonstrate the potential adverse clinical outcome of patients in the absence of clinical intervention. Two studies2 3 used a rating scale that was used in adults.4 A study of paediatric neurosurgical patients found that initial hospital prescriptions for children differed from the preadmission prescriptions in 39% of occasions and 50% of all prescribing variations had the potential to cause moderate or severe discomfort or clinical deterioration.2 A study by Coffey et al in general paediatric admissions in Canada showed 22% of patients experienced at least one discrepancy and 29% of the discrepancies had the potential to cause moderate or severe discomfort or clinical deterioration.3 By comparison an epidemiological study in discrepancies in adults on admission had 38.6% of the discrepancies identified with a potential to cause moderate or severe discomfort or clinical deterioration.4 All the studies involved small samples or specific patient groups such as medically complex patients. However all of the studies demonstrated that discrepancies occurred among paediatric populations during transitions in care settings and mentioned MR as an intervention. Conclusion: The results have shown that discrepancies of medication upon hospital admission, transfer and discharge occur regularly in children. With only one published study in the UK looking at hospital admission in children, and no published articles on the incidence and epidemiology of medication discrepancies upon hospital transfer or discharge further research is required in a wider paediatric population. Further work is also required to define the required interventions to improve practice.