Yow- Bill Wu

The impact of centering first-level predictors on individual and contextual effects in Multilevel data analysis

BackgroundMultilevel data analysis is a powerful analytical tool. Properly applying the models and correctly interpreting the findings are two interrelated general issues in using multilevel modeling (MLM). There are two specific issues when using MLM: (a) separating the individual-level effects of a predictor variable from its contextual effects and (b) centering first-level predictor variables. This can have major implications for interpreting the results at higher levels, and its impact on second-level interpretation is not always apparent. ObjectivesThe major purposes of this article are to show how to separate organizational-level effects from individual-level effects and to show how first-level centering decisions affect the interpretation of second-level coefficients. MethodsThe hierarchical linear models (HLM) are used to analyze a hypothetical data set with 385 patients nested within 10 hospitals, using uncentered, group-mean-centered, and grand-mean-centered versions of the predictor variable. ResultsUncentered and grand-mean-centered models are equivalent, but group-mean-centered models are not equivalent to the other two. For the grand-mean-centered and uncentered models, second-level coefficients provide correct estimates of the individual effect and the contextual effect when the contextual predictor variable is included in the second-level model. The group-mean-centered model leads to a second-level coefficient where individual-level effects are confounded with contextual-level effects. DiscussionThere is no single best answer to the question of whether to use group-mean centering or grand-mean centering. The theory and specific questions to be answered should be the researchers guide to selecting which centering approach to use. Understanding the implications of first-level centering is essential to interpreting second-level coefficients correctly.

Psychometric testing of four transtheoretical model questionnaires for the behavior, completing health care proxies

The purpose of the study was to develop four questionnaires based on the transtheoretical model (TTM) to assess the behavior, completing a healthcare proxy (HCP). The aims were to (a) operationalize the four TTM constructs for completing a HCP and (b) evaluate the psychometric properties of the questionnaires. The questionnaires were constructed and content validity established using an expert panel. Internal consistency values for each questionnaire and subscales within each questionnaire were >.79. Confirmatory factor analysis provided evidence that decisional balance and the processes of change questionnaires each contained two factors. Our data support validity and reliability of the TTM questionnaires related to HCP completion.

A comparison of traditional approaches to hierarchical linear modeling when analyzing longitudinal data

Longitudinal designs typically involve repeated time-ordered observations for each individual (or unit). Such designs are uniquely suited to studying changes over time within individuals, and relating these to individual characteristics to identify processes and causes of intra- individual changes and interindividual differences in physiologic and psychological development. The purpose of this paper is to compare and contrast univariate and multivariate ANOVA with repeated measures to hierarchical linear modeling as approaches to analyzing such longitudinal data. This will enable researchers to choose the approach that best meets their research needs, and it will enable them to compare research results that are reported using one analytical approach with results that are reported using the other approach.

Depression, anxiety, and suicidal ideation among Chinese Americans: a study of immigration-related factors.

Abstract The aim of this study was to identify anxiety, depression, and suicidal ideation disparities among Chinese Americans and how immigration-related factors affected the outcomes. We tried to explain the differences as a function of the Chinese culture. Data were derived from the National Latino and Asian American Study, the first national epidemiological survey of these populations in the United States. We used only the Chinese sample (N = 600) and focused on depressive disorder, anxiety disorder, and suicidal ideation. The United States–born Chinese and those Chinese who immigrated to the United States at 18 years or younger were at higher risk for lifetime depressive or anxiety disorders or suicidal ideation than were their China-born counterparts who arrived in the country at or after 18 years of age. For Chinese Americans, immigration-related factors were associated with depression and anxiety disorders and suicidal ideation. The higher prevalence of these disorders might be attributed to the psychological strains experienced by those who are at higher risk of cultural conflicts.

Frequent Emergency Department Utilization and Behavioral Health Diagnoses

BackgroundThere are 12 million emergency department (ED) visits each year related to behavioral health diagnoses. Frequent ED utilization among subpopulations, such as those with behavioral health diagnoses, flags the need for more accessible and effective healthcare delivery systems. Reducing frequent ED use is essential to controlling healthcare cost and poor outcomes of ED overcrowding. ObjectivesThe purpose of this study is to stratify individuals by overall health complexity and examine the relationship of behavioral health diagnoses (psychiatric and substance abuse) as well as frequent treat-and-release ED utilization in a cohort of Medicaid recipients. MethodsThis study was a retrospective analysis of 2009 Medicaid claims from two Western New York State counties. The claims represented 56,491 individuals (18–64 years old). Individuals were stratified into four separate cohorts for analysis based on underlying disease complexity. Data were analyzed using logistic regression models. ResultsThe following factors significantly increased the odds of frequent treat-and-release ED use in all the four complexity cohorts: psychiatric diagnosis (ORs = 1.4–2.3), substance abuse (ORs = 2.4–3.8), and smoking (ORs = 1.7–4.0). Medicaid patients with behavioral health diagnoses show high risk of frequent treat-and-release ED use. DiscussionThe results of this study show that psychiatric diagnosis, substance abuse, and smoking are associated with increased odds of frequent treat-and-release ED utilization for Medicaid recipients in all categories of underlying disease complexity. Our findings support associations reported in the literature.

Multi-level model of missed nursing care in the context of hospital merger.

The aim of this study was to delineate the multi-level relationships of individual registered nurse (RN) and nursing unit factors on missed nursing care. This was a quantitative model-building study using a descriptive, cross-sectional design. Surveys (N = 553) and administrative unit records from nurses in one hospital system undergoing merger were included. The results showed that 36% of the variation in missed nursing care is due to the unit context, with a corresponding 64% due to individual nurse differences. At the unit level, workload, skill mix, and critical unit type affected the amount of missed nursing care. At the individual nurse level, more experience, supplies problems, communication problems, and involvement in errors of commission all increased the perception of the amount of missed nursing care. Education level was not related to the amount of missed nursing care. The findings highlight the importance of unit- and individual-level interventions to redesign hospital nursing care.

Applying the transtheoretical model to health care proxy completion.

Background. For many, an important health decision is whether or not to document end-of-life wishes using an advance directive (e.g., health care proxy). To date, interventions targeting this health behavior have had little effect on increasing advance directive completion rates. Health behavior models, such as the transtheoretical model (TTM) could be useful for understanding the health decision-making processes used along a continuum, from no intention to complete an advance directive to completing one and discussing it with an appointed advocate. Purpose. To explore the applicability of the TTM for a previously understudied health behavior—completing a health care proxy (HCP). Method. Four established TTM measures for completing a HCP (stages of change, processes of change, decisional balance, and self-efficacy) were administered to 566 adults with coverage from 1 of 2 health insurance companies. Separate analyses of variance were used to test the relationships between the independent variable (stages of change) and dependent variables (processes of change, decisional balance, self-efficacy scores). Results. Consistent with other TTM research both the experiential and the behavioral processes of change revealed the lowest scores in the precontemplation stage peaking in the preparation stage. The pattern of pros and cons was replicated from previous TTM studies, with the 2 scores crossing over just prior to the preparation stage. Self-efficacy scores incrementally increased across the stages of change with the largest effect evident from the precontemplation to preparation stage. Conclusion. The models developed from this study can be used to guide the development of stage-based interventions for promoting health care proxy completion.

The relationship between acculturation and oral contraceptive use among Korean immigrant women

We explored the relationship between acculturation and beliefs, attitudes, norms, and intention regarding oral contraceptive use among Korean immigrant women using acculturation and the theory of reasoned action (TRA) as the frameworks. A total of 1,494 Korean surname-based telephone numbers were sampled in New York City. One hundred forty-five Korean immigrant women completed a telephone survey. The findings support the assumption that acculturation affects intention to use oral contraceptives indirectly only through one or more of the TRA components. Acculturation could function as an antecedent to changes in beliefs, attitudes, norms, and intention in this population. Acculturation assessment tools could provide health professionals insight into how to better approach this population on such culturally sensitive health issues as contraceptive use.

Comparative Effectiveness of Risk-Stratified Care Management in Reducing Readmissions in Medicaid Adults With Chronic Disease.

Hospitalized adult Medicaid recipients with chronic disease are at risk for rehospitalization within 90 days of discharge, but most research has focused on the Medicare population. The purpose of this study is to examine the impact of population-based care management intensity on inpatient readmissions in Medicaid adults with pre-existing chronic disease. Retrospective analyses of 2,868 index hospital admissions from 2012 New York State Medicaid Data Warehouse claims compared 90-day post-discharge utilization in populations with and without transitional care management interventions. High intensity managed care organization interventions were associated with higher outpatient and lower emergency department post-discharge utilization than low intensity fee-for-service management. However, readmission rates were higher for the managed care cases. Shorter time to readmission was associated with managed care, diagnoses that include heart and kidney failure, shorter length of stay for index hospitalization, and male sex; with no relationship to age. This unexpected result flags the need to re-evaluate readmission as a quality indicator in the complex Medicaid population. Quality improvement efforts should focus on care continuity during transitions and consider population-specific factors that influence readmission. Optimum post-discharge utilization in the Medicaid population requires a balance between outpatient, emergency and inpatient services to improve access and continuity.

Complexity of Chronic Conditions’ Impact on End-of-Life Expense Trajectories of Medicare Decedents

OBJECTIVE The aim of this study is to determine if the pattern of monthly medical expense can be used to identify individuals at risk of dying, thus supporting providers in proactively engaging in advanced care planning discussions. BACKGROUND Identifying the right time to discuss end of life can be difficult. Improved predictive capacity has made it possible for nurse leaders to use large data sets to guide clinical decision making. METHODS We examined the patterns of monthly medical expense of Medicare beneficiaries with life-limiting illness during the last 24 months of life using analysis of variance, t tests, and stepwise hierarchical linear modeling. RESULTS In the final year of life, monthly medical expense increases rapidly for all disease groupings and forms distinct patterns of change. CONCLUSION Type of condition can be used to classify decedents into distinctly different cost trajectories. Conditions including chronic disease, system failure, or cancer may be used to identify patients who may benefit from supportive care.