Evaluating Community-Based Translational Interventions Using Historical Controls: Propensity Score vs. Disease Risk Score Approach

Many community-based translations of evidence-based interventions are designed as one-arm studies due to ethical and other considerations. Evaluating the impacts of such programs is challenging. Here, we examine the effectiveness of the lifestyle intervention implemented by the Special Diabetes Program for Indians Diabetes Prevention (SDPI-DP) demonstration project, a translational lifestyle intervention among American Indian and Alaska Native communities. Data from the landmark Diabetes Prevention Program placebo group was used as a historical control. We compared the use of propensity score (PS) and disease risk score (DRS) matching to adjust for potential confounder imbalance between groups. The unadjusted hazard ratio (HR) for diabetes risk was 0.35 for SDPI-DP lifestyle intervention vs. control. However, when relevant diabetes risk factors were considered, the adjusted HR estimates were attenuated toward 1, ranging from 0.56 (95% CI 0.44–0.71) to 0.69 (95% CI 0.56–0.96). The differences in estimated HRs using the PS and DRS approaches were relatively small but DRS matching resulted in more participants being matched and smaller standard errors of effect estimates. Carefully employed, publicly available randomized clinical trial data can be used as a historical control to evaluate the intervention effectiveness of one-arm community translational initiatives. It is critical to use a proper statistical method to balance the distributions of potential confounders between comparison groups in this kind of evaluations.

     

Predictors of performance on the MMSE and the DRS-2 among American Indian elders

Little is known about factors that predict older American Indians' performance on cognitive tests. This study examined 137 American Indian elders' performance on the MMSE and the Dementia Rating Scale-Second Edition (DRS-2). Multivariate regression identified younger age, more education, not receiving Supplemental Security Income, and frequent receipt of needed health care as predictors of better performance on the MMSE. Better performance on the DRS-2 was predicted by more education, boarding school attendance, not receiving Supplemental Security Income, and frequent receipt of needed health care. This study points to the importance of economic and educational factors on cognitive test performance among American Indian elders.     

The Mixed Evidence for Brief Intervention in Emergency Departments,Trauma Care Centers,and Inpatient Hospital Settings: What Should We Do?

Background: This qualitative review is based on a symposia presented at the 2009 annual conference of the Research Society on Alcoholism (Baird et al., 2009; Field et al., 2009; Monti et al., 2009; Saitz et al., 2009a). The purpose is to describe the mixed evidence supporting brief interventions in the emergency department, trauma care, and in‐patient medical care settings; examine potential moderators of treatment outcome in light of the mixed evidence; and identify methods to move the research and practice of brief interventions beyond their current state. Methods: By drawing upon existing reviews and selected individual studies, we provide examples that reflect the current complexity of research in this area and propose steps for advancing the field. Results: Emergency departments, inpatient hospital settings, and trauma care settings represent three unique contexts within which brief interventions have been tested. While the general efficacy of brief alcohol interventions in these settings has been recognized, the evidence is increasingly mixed. Recent studies investigating potential moderators of treatment outcomes suggest that a more sophisticated approach to evaluating the effectiveness of brief interventions across varying patient populations is needed to further understand its effectiveness. Conclusions: Current dissemination efforts represent a significant advance in broadening the base of treatment for alcohol problems by providing an evidence‐based intervention in health care settings and should not be curtailed. However, additional research is required to enhance treatment outcomes, refine current practice guidelines, and continue to bridge the gap between science and practice. Given the current state of research, a multisetting clinical trial is recommended to account for potential contextual differences while controlling for study design.     

Health benefits of 'grow your own' food in urban areas: implications for contaminated land risk assessment and risk management?

Compelling evidence of major health benefits of fruit and vegetable consumption, physical activity, and outdoor interaction with 'greenspace' have emerged in the past decade - all of which combine to give major potential health benefits from 'grow-your-own' (GYO) in urban areas. However, neither current risk assessment models nor risk management strategies for GYO in allotments and gardens give any consideration to these health benefits, despite their potential often to more than fully compensate the risks. Although urban environments are more contaminated by heavy metals, arsenic, polyaromatic hydrocarbons and dioxins than most rural agricultural areas, evidence is lacking for adverse health outcomes of GYO in UK urban areas. Rarely do pollutants in GYO food exceed statutory limits set for commercial food, and few people obtain the majority of their food from GYO. In the UK, soil contamination thresholds triggering closure or remediation of allotment and garden sites are based on precautionary principles, generating 'scares' that may negatively impact public health disproportionately to the actual health risks of exposure to toxins through own-grown food. By contrast, the health benefits of GYO are a direct counterpoint to the escalating public health crisis of 'obesity and sloth' caused by eating an excess of saturated fats, inadequate consumption of fresh fruit and vegetables combined with a lack of exercise. These are now amongst the most important preventable causes of illness and death. The health and wider societal benefits of 'grow-your-own' thus reveal a major limitation in current risk assessment methodologies which, in only considering risks, are unable to predict whether GYO on particular sites will, overall, have positive, negative, or no net effects on human health. This highlights a more general need for a new generation of risk assessment tools that also predict overall consequences for health to more effectively guide risk management in our increasingly risk-averse culture.     

Positive- and negative peer modelling effects on young children's consumption of novel blue foods

Objective: The effects of positive- and negative peer modelling on children's consumption of a novel blue food, presented in each of four snack meals during an “activity” day, were evaluated. It was predicted that: (i) novel food consumption would increase after positive modelling, but decrease after negative modelling; (ii) modelling effects would generalise to a second novel blue food when participants were alone when they ate their snack; (iii) that positive modelling would reverse the effects of negative modelling. Design: A mixed design was employed with random assignment to either Groups A, B, or C (equal numbers of males and females per group). Within groups, each participant received the novel food on four snack occasions. Group A received positive modelling of blue food consumption on the first and third occasions, but were alone when they received the foods on the second and fourth occasions; Group B had negative modelling on the first occasion, positive modelling on the third, and ate alone on the second and fourth; Group C ate alone on all four occasions. To measure generalisation, an additional blue food was presented in all second and fourth “alone” occasions. Participants: Thirty-five 5–7-year olds took part in Study 1, and 44 3–4-year olds in Study 2. Results: All main predictions were confirmed except that positive peer modelling did not reverse the effects of negative modelling in the 3–4-year olds. Conclusion: Negative peer modelling inhibits novel food consumption, and its effects are particularly difficult to reverse in younger children.     

Predictors of placebo group decline in the Alzheimer's disease Assessment Scale-cognitive subscale (ADAS-Cog) in 24 week clinical trials of Alzheimer's disease

One limitation of several recent 24 week Alzheimer's disease (AD) clinical trials was the lack of cognitive decline detected by the AD Assessment Scale-cognitive subscale (ADAS-cog) in the placebo groups, possibly obscuring true medication effects. Data from 733 individuals in the placebo arms of six AD clinical trials performed 1996-1997 were pooled to examine the relationship of clinical, demographic, and genetic characteristics with the 24 week change in ADAS-cog. Baseline cognitive and functional status and the screening-to-baseline change in ADAS-cog were the strongest independent predictors of the 24 week change in ADAS-cog. The ADAS-cog did not detect progression in patients with mild dementia (screening Mini-Mental State Exam, MMSE, >or=20). The change in ADAS-cog from screening to baseline was inversely correlated with the 24 week change score; it was more difficult to detect cognitive decline at 24 weeks if individuals markedly worsened from screening to baseline. The effects of baseline MMSE and screening-to-baseline change in ADAS-cog generalized to the placebo group (N=106) of another AD study performed in 2004-2005. Overcoming lack of placebo decline in AD clinical trials will require scales more sensitive to cognitive decline in mild AD and strategies to reduce within-person variability in outcome measures.