The use of propensity scores to control for pretreatment imbalances on observed variables in non-randomized or observational studies examining the causal effects of treatments or interventions has become widespread over the past decade. For settings with two conditions of interest such as a treatment and a control, inverse probability of treatment weighted (IPTW) estimation with propensity scores estimated via boosted models has been shown in simulation studies to yield causal effect estimates with desirable properties. There are tools (e.g., the twang package in R) and guidance for implementing this method with two treatments. However, there is not such guidance for analyses of three or more treatments. The goals of this paper are two-fold: (1) to provide step-by-step guidance for researchers who want to implement propensity score weighting for multiple treatments and (2) to propose the use of generalized boosted models (GBM) for estimation of the necessary propensity score weights. We define the causal quantities that may be of interest to studies of multiple treatments and derive weighted estimators of those quantities. We present a detailed plan for using GBM to estimate propensity scores and using those scores to estimate weights and causal effects. Tools for assessing balance and overlap of pretreatment variables among treatment groups in the context of multiple treatments are also provided. A case study examining the effects of three treatment programs for adolescent substance abuse demonstrates the methods.

Using data (n=60,775 women) from the Women’s Health Initiative Clinical Trial (WHI CT)— a national study of postmenopausal women aged 50 to 79 years — we analyzed cross-sectional associations between the availability of different types of food outlets in the 1.5 miles surrounding a woman’s residence, census tract neighborhood socioeconomic status (NSES), body mass index (BMI) and blood pressure (BP). We simultaneously modeled NSES and food outlets using linear and logistic regression models, adjusting for multiple socio-demographic factors, population density and random effects at the tract and metropolitan statistical area (MSA) level. We found significant associations between NSES, availability of food outlets and individual-level measurements of BMI and BP. As grocery store/supermarket availability increased from the 10th to the 90th percentile of its distribution, controlling for confounders, BMI was lower by 0.30 kg/m2. Conversely, as fast-food outlet availability increased from the 10th to the 90th percentile, BMI was higher by 0.28 kg/m2. When NSES increased from the 10th to the 90th percentile of its distribution, BMI was lower by 1.26 kg/m2. As NSES increased from the 10th to the 90th percentile, systolic and diastolic BP were lower by 1.11 mm and 0.40 mm Hg, respectively. As grocery store/supermarket outlet availability increased from the 10th and 90th percentiles diastolic BP was lower by 0.31 mm Hg. In this national sample of post-menopausal women, we found important independent associations between the food and socioeconomic environments and BMI and BP. These findings suggest that changes in the neighborhood environment may contribute to efforts to control obesity and hypertension.

A simple and reliable grading system for keratoconus was developed that can be largely automated. Such a grading scheme could be useful in genetic studies for a complex trait such as keratoconus requiring a quantitative measure of disease presence and severity.

Objectives We examined whether neighborhood socioeconomic status (NSES) was associated with cognitive functioning in older US women, and whether this was explained by associations between NSES and vascular, health behavior, and psychosocial factors. Methods Women ages 65–81 (N=7,479) free of dementia enrolled in the Women’s Health Initiative Memory Study. Linear mixed models examined the cross-sectional association between an NSES index (0–100) and loge-transformed cognitive functioning scores. A base model adjusted for age, race/ethnicity, education, income, marital status, and hysterectomy. Three groups of potential confounders were examined in separate models: vascular, health behavior, and psychosocial factors. Results Living in a neighborhood with a one-unit higher NSES value was associated with 0.022 standard deviations higher cognitive function (p=0.02). The association was attenuated but still marginally significant (p<0.10) after adjustment for confounders and, based on interaction tests, stronger among younger and non-white women. Conclusions The socioeconomic status of a woman’s neighborhood may influence cognitive function. This relationship is only partially explained by vascular, health behavior, or psychosocial factors. Future research will examine the longitudinal relationships between NSES, cognitive impairment and cognitive decline.

BackgroundResearch is needed to evaluate the impact of implementation support interventions over and above typical efforts by community settings to deploy evidence-based prevention programs.MethodsEnhancing Quality Interventions Promoting Healthy Sexuality is a randomized controlled trial testing Getting To Outcomes (GTO), a 2-year implementation support intervention. It compares 16 Boys and Girls Club sites implementing Making Proud Choices (MPC, control group), a structured teen pregnancy prevention evidence-based program with 16 similar sites implementing MPC augmented with GTO (intervention group). All sites received training and manuals typical for MPC. GTO has its own manuals, training, and onsite technical assistance (TA) to help practitioners complete key programming practices specified by GTO. During the first year, TA providers helped the intervention group adopt, plan, and deliver MPC. This group then received training on the evaluation and quality improvement steps of GTO, including feedback reports summarizing their data, which were used in a TA-facilitated quality improvement process that yielded revised plans for the second MPC implementation. This paper presents results regarding GTO’s impact on performance of the sites (i.e., how well key programming practices were carried out), fidelity of MPC implementation, and the relationship between amount of TA support, performance, and fidelity. Performance was measured using ratings made from a standardized, structured interview conducted with participating staff at all 32 Boys and Girls Clubs sites after the first and second years of MPC implementation. Multiple elements of fidelity (adherence, classroom delivery, dosage) were assessed at all sites by observer ratings and attendance logs.ResultsAfter 2 years, the intervention sites had higher ratings of performance, adherence, and classroom delivery (dosage remained similar). Higher performance predicted greater adherence in both years.ConclusionsThese findings suggest that in typical community-based settings, manuals and training common to structured EBPs may be sufficient to yield low levels of performance and moderate levels of fidelity but that systematic implementation support is needed to achieve high levels of performance and fidelity.Trial registrationClinicalTrials.gov, NCT01818791