Efficacy dilution in randomized placebo-controlled vaginal microbicide trials

<p>Abstract</p> <p>Background</p> <p>To date different vaginal gel microbicides have been evaluated in phase 2b/3 trials, but none have demonstrated effectiveness for preventing HIV infection. Failure to demonstrate effectiveness however does not necessarily indicate that a product is truly inefficacious, as several sources of efficacy dilution may compromise our ability to identify products that may have been truly efficacious.</p> <p>Methods</p> <p>For four individual sources of dilution, we describe the dilution mechanisms and quantify the expected effectiveness. An overall expected effectiveness that combines all sources of dilution in a trial is derived as well.</p> <p>Results</p> <p>Under conditions that have been observed in recent microbicide trials, the overall expected effectiveness assuming an active gel with true efficacy of 50% and 75% are in the range of [16%; 33%] and [28%; 50%], respectively, when considering the four major sources of dilution. In contrast the diluting effect due to adherence alone (assuming an adherence of 80%) leads to higher expected effectiveness, 40% and 60% assuming an active gel with true efficacy of 50% and 75%, respectively. Individual sources of dilution may demonstrate a small effect when evaluated independently, but the overall dilution effect in a trial with several sources of dilution can be quite substantial.</p> <p>Conclusion</p> <p>Currently planned phase 2b/3 microbicide trials of new candidate vaginal microbicides are not immune from these shortcomings. A good understanding of dilution effects is necessary to properly interpret microbicide trial results and to identify products worthy of further development and evaluation. Greater attention should be devoted to reducing and assessing the impact of efficacy dilution and to carefully selecting the effect size in the design of future trials.</p

Will web-based research suffice when collecting U.S. school district policies? The case of physical education and school-based nutrition policies

<p>Abstract</p> <p>Background</p> <p>Recognizing the growing childhood overweight problem, a number of school-based strategies, including policy approaches, have been proposed and are being implemented to address the problem considering the amount of time children spend in schools. This paper describes the results of a pilot study that tested approaches to collecting U.S. school district policy information regarding physical education and nutrition requirements that can inform efforts by policy makers, researchers, advocates and others interested in collecting school district-level obesity-related policies that are typically not systematically available from a "one stop" source.</p> <p>Methods</p> <p>Sixty local school districts representing six states were selected for conducting the district policy research, with larger, urban school districts over-sampled to facilitate collection of policies from districts representing a larger proportion of the public school population in each study state. The six states within which the pilot districts were located were chosen based on the variability in their physical education and school-based nutrition policy and geographic and demographic diversity. Web research and a mail canvass of the study districts was conducted between January and May 2006 to obtain all relevant policies. An additional field collection effort was conducted in a sample of districts located in three study states to test the extent to which field collection would yield additional information.</p> <p>Results</p> <p>Policies were obtained from 40 (67%) of the 60 districts, with policies retrieved via both Web and mail canvass methods in 16 (27%) of the districts, and were confirmed to not exist in 10 (17%) of the districts. Policies were more likely to be retrieved from larger, urban districts, whereas the smallest districts had no policies available on the Web. In no instances were exactly the same policies retrieved from the two sources. Physical education policies were slightly more prevalent than nutrition policies.</p> <p>Conclusion</p> <p>Collection of U.S. local school district policies requires a multi-pronged approach. Web research and mail canvasses will likely yield different types of policy information. Given the variance in district-level Web site presence, researchers and others interested in obtaining district physical education and nutrition-related policies should consider supplementing Web research with more direct methods.</p

The Association between Perceived Adequacy and Capacity for School Food Policy Implementation with Food Availability and Policy Adherence in Nova Scotia, Canada.

Supporting the implementation of school food and nutrition policies is an international priority to encourage healthier eating among children and youth. Schools are an important intervention setting to promote childhood nutrition, and many jurisdictions have adopted policies, guidelines, and programs to modify the school nutrition environment and promote healthier eating. The purpose of this study was to explore the association between perceived adequacy of facilities or equipment and capacity of staff to support policy implementation with food availability and policy adherence in the province of Nova Scotia (NS), Canada, one of the first regions in Canada to launch a comprehensive school food and nutrition policy (SFNP). A cross-sectional online survey was conducted in 2014-2015 to provide a current-state assessment of policy implementation and adherence. Adequacy and capacity for food policy implementation was used to assess policy adherence through the availability of prohibited 'minimum' nutrition foods. An exploratory factor analysis was conducted on a selection of available foods, and 'slow'- and 'quick'-service food composition measures were dichotomized for food availability. Schools with above-average perceived adequacy and capacity for policy implementation had greater odds (OR = 3.62, CI = 1.56, 8.40) of adhering to a lunch policy, while schools that adhered to a snack and lunch policy had lower odds (OR = 0.48, CI = 0.23, 1.01 and OR = 0.18, CI = 0.08, 0.41) of serving quick-service foods. This study identified the need for appropriate adequacy of facilities or equipment and capacity of staff for policy implementation to ensure policy adherence and improve the school food environment. These findings highlight the relationship between school food and nutrition policies, suggesting that better supporting their implementation could increase the likelihood of their success

Waiting for child developmental and rehabilitation services: an overview of issues and needs

Concern about the length of time that children, young people, and families may have to wait to access assessment, diagnostic, interventional, therapeutic, and supportive child developmental and rehabilitation (CDR) services is widespread, but adequate data collection and research on this issue remain limited. We review key concepts and issues relevant to waiting for CDR services from the published literature, a national workshop devoted to this topic, and international experience. We conclude that gaps in data, evidence, and consensus challenge our ability to address the issue of waiting for CDR services in a systematic way. A program of research coupled with actions based on consensus-building is required. Research priorities include acquiring evidence of the appropriateness and effectiveness of different models of intervention and rehabilitation services, and documenting the experience and expectations of waiting families. Consensus-building processes are critical to identify, categorize, and prioritize \u27sentinel\u27 components of CDR service pathways: (1) to reduce the inherent complexity of the field; (2) to create benchmarks for waiting for these respective services; and (3) to develop definitions for wait-time subcomponents in CDR services. Collection of accurate and replicable data on wait times for CDR services can be used to document baseline realities, to monitor and improve system performance, and to conduct comparative and analytic research in the field of CDR services

COMPARING THE VALIDITY OF FIVE PARTICIPATION INSTRUMENTS IN PERSONS WITH SPINAL CONDITIONS

Objective: To evaluate and compare the construct validity of 5 participation instruments developed using the International Classification of Functioning, Disability and Health (ICF). Methods: A total of 545 subjects diagnosed and treated for a spinal condition at an acute hospital were followed-up and consented to complete a questionnaire. Subjects completed 5 participation instruments (Impact on Participation and Autonomy (IPA), Keele Assessment of Participation (KAP), Participation Measure-Post Acute Care (PM-PAC), Participation Objective Participation Subjective (POPS), World Health Organization Disability Assessment Schedule II (WHODAS II)). In addition, each subject completed a health status instrument and a quality of life instrument. The dimensionality, convergent/discriminant validity and known-group validity of the participation instruments were assessed. Results: A confirmatory factor analysis of the facture structure for the IPA and PM-PAC demonstrated adequate model fit. For convergent/discriminant validity, correlations were generally higher among similar domains of the WHODAS II, IPA, KAP and PM-PAC, and as expected the lowest correlations were observed with the objective domains of the POPS. Most instruments demonstrated known-group validity. Conclusion: Differences in the construct validity evidence of the POPS compared with the other 4 instruments were noted. To date, there is no gold standard for measuring participation, and clinicians and researchers should consider the type of information required prior to selecting an instrument

Constructing indices representing supportiveness of the physical environment for walking using the Rasch measurement model

BACKGROUND: The objectives of this study were to use the Rasch model to 1) assess the psychometric properties of a physical environmental audit instrument and 2) to develop indices of interrelated environmental attributes that summarize environmental supportiveness for walking. METHODS: A set of items were derived representing two conceptual physical environmental constructs: 1) functional/safety, and; 2) aesthetics. Ad hoc criteria based on point-biserial and Rasch-based fit statistics were used to examine the construct validity and internal reliability of the two constructs. RESULTS: The Rasch-based fit statistics assisted in identifying 12 items that belonged to the functional/safety construct and 4 items that belonged to the aesthetic construct. The reliability of the two constructs were low to moderate (functional/safety r(β )= 0.19 and aesthetics r(β )= 0.35). CONCLUSION: Given the vast number of built environmental attributes, a means of developing summary indices is essential. Future studies should assess the reliability and validity of indices that summarize physical environmental characteristics conducive to walking before testing them in predictive models of physical activity. More research examining procedures for measuring the built environment and techniques for analyzing environmental data are needed to guide future research in this area

Introducing equating methodologies to compare test scores from two different self-regulation scales

Abstract Standardizing the measurement tools that researchers use to assess the effectiveness of interventions would strengthen our ability to compare results across studies. In practice, however, standardization is difficult to implement, in part, because researchers prefer to use measurement tools that focus specifically on the components of their interventions. This paper demonstrates the usefulness of item response modeling linking methodology in comparing groups of participants who were administered different scales intended to measure the same underlying constructs. The Treatment Self-Regulation Questionnaire (TSRQ) as it relates to diet improvement provided the empirical application to demonstrate how two different scales that measure the same construct can be compared. The results showed that two eight-item TSRQ scales can be linked if they have at least four items in common. As expected, varying the number of linking items did not affect the reliability of the results; however, it significantly affected the relative rating with respect to the 15-item scale. In health behavior and health education research, linking methodologies can be used to compare results across studies that use slightly different versions of a scale to measure the same construct