Longitudinal functional recovery after postacute rehabilitation in older hip fracture patients: the role of cognitive impairment and implications for long-term care.

OBJECTIVE: To compare functional recovery patterns of cognitively impaired and nonimpaired older adults who had hip fracture surgeries, and to identify associated long-term care needs. METHODS: Longitudinal study (n = 231). Data were collected within 72 hours of admission to and before discharge from the postacute rehabilitation facilities and at 2, 6, and 12 months following postacute rehabilitation discharge. Six functional independence measures (FIM) were used to assess functional recovery. Mini-mental status examination was used to gauge cognitive function. Mixed-effects analyses quantify differences of FIM functional recovery patterns between groups while adjusting for potential confounders. RESULTS: Multivariate results showed that patients with impaired cognition had notably different functional recovery patterns and significantly worse overall FIM scores (P < .001) than their counterparts in all 6 FIM functions. For locomotion function at 1 year, cognitively nonimpaired patients needed little supervision (mean FIM = 5.6), whereas patients with impaired cognition needed 50% human assistance (FIM = 3.9). In addition to needing locomotion assistance, cognitively impaired patients also required 25% human assistance in transfers (FIM = 4.8), 25% in self-care (FIM mean = 5.3), and 25% in sphincter control (FIM mean = 5.0). CONCLUSION: Cognitively impaired patients experienced recovery at 2 and 6 months but were unable to retain rehabilitation gains in locomotion, transfers, self-care, and sphincter control at 1 year following postacute rehabilitation discharge, and they still required human assistance to stay in their homes within the community. To prevent or delay nursing home entry, it is suggested that appropriate long-term care planning and social support for caregivers are needed for cognitively impaired hip fracture patients.

Introduction to the Special Issue on Propensity Score Methods in Behavioral Research.

This issue includes six articles that present logic, methods, and models for causal analyses of observational data, in particular those based on propensity score (PS) methods. The articles include a general introduction to propensity score analysis (PSA), uses of PSA in mediation studies, issues involved in choosing covariates, challenges that often arise in PSA applications, hierarchical data issues and models, and an application in an educational testing context. In this editorial I briefly summarize each article and make a few recommendations that relate to future applications in this field: the first pertains to how propensity score (PS) work could profit by connecting it with stronger forms of randomized experiments, not just simple randomization; the second to how and why graphical methods could be used to greater advantage in PSA studies; then why it might be helpful to reconsider the meaning of the term "treatments" in observational studies and why conventional usage might be modified; and finally, to the distinction between retrospective and prospective approaches to observational study design, noting the advantages, when feasible, of the latter approach.

Abstract: An International Comparison of Private and Public Schools Using Multilevel Propensity Score Methods and Graphics.

As can be seen from the recent Special Issue of MBR on propensity score analysis (PSA) methods, the use of PSA has gained increasing popularity for estimating causal effects in observational studies. However, PSA use with multilevel or clustered data has been limited, and to date there seems to have been no development of specialized graphics for such data. This paper introduces the multilevelPSA ( http://multilevelPSA.r-forge.r-project.org ) package for R that provides cluster-based functions for estimating propensity scores as well as graphics to exhibit results for multilevel data. This work extends to the multilevel case the framework for visualizing propensity score analysis introduced by Helmreich and Pruzek (2009). International data from the Programme for International Student Assessment (Organization for Economic Co-operation and Development, 2009) are comprehensively examined to compare private with public schools on reading, mathematics, and science outcomes after adjusting for covariate differences in the multilevel context. Particularly for analyses of large data sets, focusing on statistical significance is limiting. As can readily be seen, overall results favor "private" over "public" schools, at least for end of secondary school math achievement. But the graphics provide a more nuanced understanding of the nature and magnitude of adjusted differences for countries. Furthermore, the graphics are readily interpreted by a nontechnical audience. Broadly speaking, it is seen that modern graphics can enhance and extend conventional numerical summaries by focusing on details of what data have to say for multilevel comparisons of many countries based on propensity score methods.

Examining heterogeneity of functional recovery among older adults with hip fractures.

OBJECTIVE: To examine heterogeneity in 1-year functional recovery following postacute rehabilitation among older adults with hip fracture. METHODS: Two hundred twenty-five community-dwelling older adults with hip fracture who received postacute rehabilitation in 5 rehabilitation facilities in Baltimore, Maryland, were recruited during postacute rehabilitation (baseline) and follow-up at 2, 6, and 12 months following postacute rehabilitation discharge. Functional recovery was measured by the activities of daily living (ADL) and instrumental activities of daily living (IADL) scores. A mixed-effect model was used to examine factors associated with postacute rehabilitation functional recovery; fixed and random effects estimates from the models were used to demonstrate heterogeneity in functional recovery. RESULTS: Results indicated that there was an overall trend in both ADL and IADL functional improvement at 2 months following postacute rehabilitation, with continued improvement to 6 months, after which functional recovery slowed down and remained constant through the year. Individuals whose functional recovery did not conform to these patterns were identified and their functional recovery that deviated substantially from the group mean was demonstrated. CONCLUSIONS: Functional recovery patterns in elderly hip fracture patients are heterogeneous. To foster functional independence, health care professionals should consider individual recovery trajectories using a modeling approach appropriate for longitudinal or repeated measurement data such as a linear mixed-effects model when designing individualized rehabilitation and postacute rehabilitation care plans.

Rapid infant weight gain predicts childhood overweight.

OBJECTIVE: To determine among a contemporary cohort whether rapid weight gain between birth and 6 months is associated with risk of childhood overweight and if this risk differs by ethnicity and/or breast-feeding history. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional survey in 1999 to 2000 of parents/guardians of children participating in the Special Supplemental Nutrition Program for Women, Infants, and Children in New York State. Measurements were abstracted by chart review, including weight at birth and 6 months, and height and weight at time of survey and every 6 months subsequently. Overweight at 4 years of age was defined as a BMI > or = 95th age- and sex-specific percentiles. RESULTS: The study sample was 32% Hispanic, 19% black, and 49% white; 17% of children were overweight. Rate of infant weight gain (expressed in terms of 100 g/mo) was significantly associated with being overweight at 4 years (odds ratio, 1.4; 95% confidence interval, 1.3 to 1.6 after adjusting for history of breast-feeding, birth weight, and ethnicity). The odds of being overweight at 4 years of age for Hispanic children were twice those of non-Hispanic children (odds ratio, 2.2; 95% confidence interval, 1.5 to 3.3). The population-attributable risk of overweight at 4 years of age was 19% for children in the highest quintile of infant weight gain. DISCUSSION: Among this contemporary, multi-ethnic cohort, rapid infant weight gain was associated with increased risk of being overweight at 4 years of age, independently of potential confounders. Identification of the risk factors contributing to rapid weight gain during infancy might improve early recognition and guide strategies for optimal nutrition to prevent the development of childhood overweight.

Overweight trends among children enrolled in the New York State special supplemental nutrition program for women, infants, and children.

The objective of this study is to describe overweight trends in a large, multiethnic, low-income population of preschool children by race/ethnicity and examine cohort changes in body mass index (BMI) distribution. Cross-sectional data were collected January 1 through March 31, every year, from 1989 to 2003. Subjects were children aged 2 to 4 years participating in the Special Supplemental Nutrition Program for Women, Infants, and Children in New York State. The prevalence of overweight (BMI > or =95th age- and sex-specific percentile of the 2000 Centers for Disease Control and Prevention growth charts) was calculated for each year. Least squares regression compared trends in prevalence by race/ethnicity. Changes in BMI distribution were assessed graphically. Overweight prevalence increased 33% (12% to 16%). Prevalence was highest for Hispanics and lowest for non-Hispanic whites. Rates of increase (0.28 percentage points per year) were the same for Hispanic, non-Hispanic black, and non-Hispanic white children. The BMI distribution shifted toward higher values for all children studied; for 3- and 4-year-old children, the difference increased as BMI increased, indicating that, in 2003, the heaviest children were considerably heavier than the heaviest children were in 1989.

A comparative analysis of effects of early versus late prenatal WIC participation on birth weight: NYS, 1995.

OBJECTIVES: This study examined the effects of prenatal participation in the NYS WIC Program on birth weight through enhanced control of selection bias and gestational age bias. Program effects were assessed separately for White, Black, and Hispanic women and subpopulations defined by values of Kotelchuck index of adequacy of prenatal care utilization. METHODS: 1995 New York State Vital Statistics records were linked to WIC certifications, administrative and check redemption files, and to the 1990 federal census of NY county level data. The final data set contained 77,601 records. Birth weight among WIC participants who enrolled early and participated longer were compared to those who enrolled late and participated a shorter time. Selection bias was addressed using classification tree methods as part of a propensity score analysis. Gestational age bias was addressed by analyzing preterm and full-term pregnancies separately. RESULTS: Adjusted estimates showed a significant positive effect of longer prenatal WIC participation on birth outcomes for all groups studied. Infants born to WIC participants who enrolled early were heavier than those who enrolled late by, on average, 70 g for full-term and 129 grams for preterm. Black and Hispanic full-term infants experienced larger WIC effects than Whites (79, 75, 43 g, respectively). Looking at full-term pregnancies using Kotelchuck's index indicated that effects of longer prenatal WIC participation were greatest for the inadequate prenatal care group (83 g). CONCLUSION: Longer prenatal WIC participation was associated with an increase in birth weight overall and for all groups studied. The effect on birth weight of longer participation in WIC was greatest in Black and Hispanic, inadequate and no prenatal care groups.

Barriers to the use of WIC services.

OBJECTIVES: To identify barriers that deter parents/caretakers of infants and children enrolled in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) from taking full advantage of the services provided by the program. SUBJECTS/SETTING: A total of 3,167 parents/caretakers at 51 New York State WIC local agency sites completed a barriers survey. DESIGN: Sixty-eight potential barriers to WIC were identified through a literature review, five focus groups with parents/caretakers of WIC participants, and an expert review panel. The barriers survey was administered person-to-person to parents/caretakers of infants and children on WIC. Statistical analysis Classification tree analysis was used to identify characteristics that best predict WIC check usage behavior. RESULTS: A small set of barriers (n=11) were identified by more than 20% of respondents. Waiting too long was the most frequently cited barrier (48%). Difficulties in bringing the infant/child to recertify and rescheduling appointments were key variables associated with failure to use (ie, pick up or cash) WIC checks. Further analyses indicated that (a) for each additional reported barrier, there was a 2% increase in failure to use WIC checks (P<.0001); (b) waiting for services was related to an increase in the number of people who failed to use checks; and (c) the longer the reported wait, the greater the number of reported barriers (P<.0001). CONCLUSIONS: Conducting this barriers research enabled the New York State WIC to improve services provided to participants and their families. A decrease in waiting times should generally reduce exposure to noisy, crowded facilities and lead to fewer reports of nothing for kids to do.