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Browsing by Author "Tu, Wanzhu"
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Item A Contextual Approach to the Psychological Study of Identity Concealment: Examining Direct, Interactive, and Indirect Effects of Structural Stigma on Concealment Motivation Across Proximal and Distal Geographic Levels(Sage, 2021) Lattanner, Micah R.; Ford, Jessie; Bo, Na; Tu, Wanzhu; Pachankis, John E.; Dodge, Brian; Hatzenbuehler, Mark L.; Biostatistics, School of Public HealthPsychological theories of identity concealment locate the ultimate source of concealment decisions within the social environment, yet most studies have not explicitly assessed stigmatizing environments beyond the immediate situation. We advanced the identity-concealment literature by objectively measuring structural forms of stigma related to sexual orientation (e.g., social policies) at proximal and distal geographic levels. We linked these measures to a new, population-based data set of 502 gay and bisexual men (residing in 44 states and Washington, DC; 269 counties; and 354 cities) who completed survey items about stigma, including identity-concealment motivation. Among gay men, the association between structural stigma and concealment motivation was (a) observed across three levels (city, county, and state), (b) conditional on one's exposure at another geographic level (participants reported the least motivations to conceal their identity if they resided in both cities and states that were lowest in structural stigma), and (c) mediated by subjective perceptions of greater structural stigma.Item A reference-free R-learner for treatment recommendation(Sage, 2023) Zhou, Junyi; Zhang, Ying; Tu, Wanzhu; Biostatistics and Health Data Science, School of MedicineAssigning optimal treatments to individual patients based on their characteristics is the ultimate goal of precision medicine. Deriving evidence-based recommendations from observational data while considering the causal treatment effects and patient heterogeneity is a challenging task, especially in situations of multiple treatment options. Herein, we propose a reference-free R-learner based on a simplex algorithm for treatment recommendation. We showed through extensive simulation that the proposed method produced accurate recommendations that corresponded to optimal treatment outcomes, regardless of the reference group. We used the method to analyze data from the Systolic Blood Pressure Intervention Trial (SPRINT) and achieved recommendations consistent with the current clinical guidelines.Item Addressing People and Place Microenvironments in Weight Loss Disparities (APP-Me): Design of a randomized controlled trial testing timely messages for weight loss behavior in low income black and white women(Elsevier, 2018) Clark, Daniel O.; Srinivas, Preethi; Bodke, Kunal; Keith, NiCole; Hood, Sula; Tu, Wanzhu; Medicine, School of MedicineBackground Behavioral interventions for weight loss have been less effective in lower income and black women. These poorer outcomes may in part be related to these women having more frequent exposures to social and physical situations that are obesogenic, i.e., eating and sedentary cues or situations. Objectives Working with obese, lower income black and white women, Addressing People and Place Microenvironments (APP-Me) was designed to create awareness of self-behavior at times and places of frequent eating and sedentary behavior. Design APP-Me is being evaluated in a randomized controlled trial with 240 participants recruited from federally qualified health centers located in a single Midwestern city. All participants complete four weeks of ecological momentary assessments (EMA) of situations and behavior. At the end of the four weeks, participants are randomized to enhanced usual care (UC) or UC plus APPMe. Methods APP-Me is an automated short messaging system (SMS). Messages are text, image, audio, or a combination, and are delivered to participants’ mobile devices with the intent of creating awareness at the times and places of frequent eating or sedentary behavior. The EMA data inform the timing of message deliveries. Summary This project aims to create and test timely awareness messages in a subpopulation that has not responded well to traditional behavioral interventions for weight loss. Novel aspects of the study include the involvement of a low income population, the use of data on time and place of obesogenic behavior, and message delivery time tailored to an individual’s behavioral patterns.Item Adiposity has unique influence on the renin-aldosterone axis and blood pressure in black children(Elsevier, 2013-11) Yu, Zhangsheng; Eckert, George; Liu, Hai; Pratt, J. Howard; Tu, Wanzhu; Medicine, School of MedicineOBJECTIVE: To comparatively examine the effects of adiposity on the levels of plasma renin activity (PRA), plasma aldosterone concentration (PAC), and aldosterone-renin ratio (ARR) in young black and white children. STUDY DESIGN: We prospectively assessed 248 black and 345 white children and adolescents. A novel analytical technique was used to assess the concurrent influences of age and body mass index (BMI) on PRA, PAC, and ARR. The estimated effects were depicted by colored contour plots. RESULTS: In contrast to whites, blacks had lower PRA (2.76 vs 3.36 ng/mL/h; P < .001) and lower PAC (9.01 vs 14.59 ng/dL; P < .001). In blacks, BMI was negatively associated with PRA (P = .001), consistent with an association with a more expanded plasma volume; there was no association with PAC. In whites, BMI was positively associated with PAC (P = .005); we did not detect a BMI-PRA association. The effects of BMI on ARR were directionally similar in the two race groups but more pronounced in blacks. Mean systolic blood pressure was greater in blacks with lower PRA (P < .01), higher PAC (P = .015), and higher ARR (P = .49). CONCLUSIONS: An increase in adiposity was associated with a suppressed PRA in blacks and an increase in PAC in whites. The unique relationship between adiposity and renin-aldosterone axis in blacks suggests the possible existence of a population-specific mechanism characterized by volume expansion, which could in turn enhance the influences of adiposity on blood pressure in black children and adolescents.Item Age Differences in the Association Between Body Mass Index Class and Annualized Medicare Expenditures(SAGE, 2016-02) Clark, Daniel O.; Lane, Kathleen A.; Ambuehl, Roberta; Tu, Wanzhu; Liu, Chiung-Ju; Unroe, Kathleen; Callahan, Christopher M.; Department of Medicine, IU School of MedicineOBJECTIVE: The aim of the study is to assess the relationship between body mass index (BMI) class and Medicare claims among young-old (65-69), old (70-74), and old-old (75+) adults over a 10-year period. METHOD: We assessed costs by BMI class and age group among 9,300 respondents to the 1998 Health and Retirement Study (HRS) with linked 1998-2008 Medicare claims data. BMI was classified as normal (18.5-24.9), overweight (25-29.9), mild obesity (30-34.9), or severe obesity (35 or above). RESULTS: Annualized total Medicare claims adjusted for age, gender, ethnicity, education, and smoking history were 109% greater for severely obese young-old adults in comparison with normal weight young-old adults (US$9,751 vs. US$4,663). Total annualized claim differences between the normal weight and severely obese in the old and old-old groups were not statistically significant. DISCUSSION: Excess Medicare expenditures related to obesity may be concentrated among severely obese young-old adults. Preventing severe obesity among middle and older aged adults may have large cost implications for society.Item Age-specific rates of hospital transfers in long-stay nursing home residents(Oxford Academic, 2022-01) Tu, Wanzhu; Li, Ruohong; Stump, Timothy E.; Fowler, Nicole R.; Carnahan, Jennifer L.; Blackburn, Justin; Sachs, Greg A.; Hickman, Susan E.; Unroe, Kathleen T.; Biostatistics, School of Public HealthIntroduction hospital transfers and admissions are critical events in the care of nursing home residents. We sought to determine hospital transfer rates at different ages. Methods a cohort of 1,187 long-stay nursing home residents who had participated in a Centers for Medicare and Medicaid demonstration project. We analysed the number of hospital transfers of the study participants recorded by the Minimum Data Set. Using a modern regression technique, we depicted the annual rate of hospital transfers as a smooth function of age. Results transfer rates declined with age in a nonlinear fashion. Rates were the highest among residents younger than 60 years of age (1.30-2.15 transfers per year), relatively stable between 60 and 80 (1.17-1.30 transfers per year) and lower in those older than 80 (0.77-1.17 transfers per year). Factors associated with increased risk of transfers included prior diagnoses of hip fracture (annual incidence rate ratio or IRR: 2.057, 95% confidence interval (CI): [1.240, 3.412]), dialysis (IRR: 1.717, 95% CI: [1.313, 2.246]), urinary tract infection (IRR: 1.755, 95% CI: [1.361, 2.264]), pneumonia (IRR: 1.501, 95% CI: [1.072, 2.104]), daily pain (IRR: 1.297, 95% CI: [1.055,1.594]), anaemia (IRR: 1.229, 95% CI [1.068, 1.414]) and chronic obstructive pulmonary disease (IRR: 1.168, 95% CI: [1.010,1.352]). Transfer rates were lower in residents who had orders reflecting preferences for comfort care (IRR: 0.79, 95% CI: [0.665, 0.936]). Discussion younger nursing home residents may require specialised interventions to reduce hospital transfers; declining transfer rates with the oldest age groups may reflect preferences for comfort-focused care.Item Aldosterone sensitivity: an opportunity to explore the pathogenesis of hypertension(American Physiological Society, 2021-03) Gray, Zachary; Tu, Wanzhu; Chertow, Glenn M.; Bhalla, Vivek; Biostatistics, School of Public HealthAldosterone sensitivity is defined as an outcome variable for a given circulating level of aldosterone. In basic and translational studies, aldosterone sensitivity has been measured in differential tissue responses, e.g., lower urine sodium and higher urine potassium, as an index of the renal response; in clinical studies, aldosterone sensitivity has been measured in differential blood pressure responses. The concept of aldosterone sensitivity disrupts the conventional wisdom of the renin-angiotensin-aldosterone system and has the potential to uncover novel mechanisms of hypertension. Here, we review basic and translational science studies that uncovered differential renal responses to aldosterone and connect this earlier work to more recent observational studies and randomized trials that have demonstrated differential blood pressure responses for a given level of aldosterone in healthy and hypertensive persons. Black race and older age are associated with higher aldosterone sensitivity and blood pressure. We also discuss gaps in the field and how future basic and clinical studies might inform mechanisms of differential sensitivity.Item ARDaC Common Data Model Facilitates Data Dissemination and Enables Data Commons for Modern Clinical Studies(IOS Press, 2024) Jin, Nanxin; Li, Zuotian; Kettler, Carla; Yang, Baijian; Tu, Wanzhu; Su, Jing; Biostatistics and Health Data Science, School of MedicineModern clinical studies collect longitudinal and multimodal data about participants, treatments and responses, biospecimens, and molecular and multiomics data. Such rich and complex data requires new common data models (CDM) to support data dissemination and research collaboration. We have developed the ARDaC CDM for the Alcoholic Hepatitis Network (AlcHepNet) Research Data Commons (ARDaC) to support clinical studies and translational research in the national AlcHepNet consortium. The ARDaC CDM bridges the gap between the data models used by the AlcHepNet electronic data capture platform (REDCap) and the Genomic Data Commons (GDC) data model used by the Gen3 data commons framework. It extends the GDC data model for clinical studies; facilitates the harmonization of research data across consortia and programs; and supports the development of the ARDaC. ARDaC CDM is designed as a general and extensible CDM for addressing the needs of modern clinical studies. The ARDaC CDM is available at https://dev.ardac.org/DD.Item Association Between Medication Adherence and the Outcomes of Heart Failure(Wiley, 2018) Hood, Sarah R.; Giazzon, Anthony J.; Seamon, Gwen; Lane, Kathleen A.; Wang, Jane; Eckert, George J.; Tu, Wanzhu; Murray, Michael D.; Biostatistics, School of Public HealthBackground Previous studies of heart failure patients have demonstrated an association between cardiovascular medication adherence and hospitalizations or a composite end point of hospitalization and death. Few studies have assessed the impact of treatment adherence within large general medical populations that distinguish the health outcomes of emergency department visits, hospitalization, and death. Objective To determine the association of incremental cardiovascular medication adherence on emergency department visits, hospitalization, and death in adult heart failure patients in Indiana. Design Retrospective cohort study conducted using electronic health record data from the statewide Indiana Network for Patient Care (INPC) between 2004 and 2009. Methods Patients were at least 18 years of age with a diagnosis of heart failure and prescribed at least one cardiovascular medication for heart failure. Adherence was measured as the proportion of days covered (PDC) using pharmacy transaction data. Clinical end points included emergency department visits, hospital admissions, length of hospital stay, and mortality. Generalized linear models were used to determine the effect of a 10% increase in PDC on clinical end points adjusting for age, sex, race, Charlson comorbidity index, and medications. Results Electronic health records were available for 55,312 patients (mean age ± standard deviation [SD] 68 ± 16 years; 54% women; 65% white). Mean PDC for all heart failure medications was 63% ± 23%. For every 10% increase in PDC, emergency department visits decreased 11% (rate ratio [RR] 0.89; 95% confidence interval [CI] 0.89‐0.89), hospital admissions decreased 6% (RR 0.94; 95% CI 0.94‐0.94), total length of hospital stay decreased 1% (RR 0.99; 95% CI 0.99‐1.00), and all‐cause mortality decreased 9% (odds ratio 0.91; 95% CI 0.90‐0.92). Conclusion Incremental medication adherence was associated with reductions in emergency department visits, hospital admissions, length of hospital stay, and all‐cause mortality.Item Association of Chlamydia trachomatis infection with redetection of human papillomavirus after apparent clearance(Oxford, 2013-11) Shew, Marcia L.; Ermel, Aaron C.; Weaver, Bree A.; Tong, Yan; Tu, Wanzhu; Kester, Laura M.; Denski, Cheryl; Fortenberry, J. Dennis; Brown, Darron R.; Pediatrics, School of MedicineBACKGROUND: Persistent infection with oncogenic human papillomavirus (HPV) is associated with an increased risk of cervical malignancy. Redetection of type-specific HPV after a period of nondetection may be caused by reactivation of a low-level persistent infection. Little is known about factors associated with type-specific HPV redetection. METHODS: For a longitudinal cohort of adolescent women with frequent behavioral and sexually transmitted infection (STI) information (every 3 months), Cox proportional hazard models were used to assess the influence of sexual behaviors and STIs on the redetection of oncogenic or high-risk HPV infections. RESULTS: A total of 210 type-specific high-risk HPV detection episode periods were identified in this longitudinal cohort; 71 (33.8%) were characterized by a period of nondetection followed by redetection. Chlamydia trachomatis (hazard ratio [HR], 3.14; 95% confidence interval [CI], 1.44-6.86) was associated with redetection; redetection was >2 times more likely with each additional self-reported sex partner in the past 3 months (HR, 2.26; 95% CI, 1.35-3.78). CONCLUSIONS: This study demonstrates the role of C. trachomatis and number of recent sexual partners in type-specific HPV redetection. Given that persistent oncogenic HPV infections are associated with cancer-related outcomes, understanding the potential role of such factors in the pathogenesis of HPV-related outcomes is important.