Food resources and kitchen skills plus aerobic training (FoRKS+) for black adults with hypertension: A pilot trial protocol.

BACKGROUND: Midlife hypertension is associated with cognitive decline and Alzheimer's disease and related dementia (ADRD), suggesting that blood pressure control may be a therapeutic target for dementia prevention. Given excess hypertension in non-Hispanic Black (NHB) adults, blood pressure control may also reduce ADRD disparities. We describe a pilot randomized controlled trial (RCT) to evaluate the feasibility and preliminary efficacy of a multicomponent lifestyle-based intervention versus enhanced usual care on cognition among middle-aged NHB adults. METHODS AND STUDY DESIGN: The Food Resources and Kitchen Skills plus Aerobic Training (FoRKS+) study is a 2-arm, single-blinded trial that compares those receiving the FoRKS+ program (target N = 64) versus those receiving enhanced usual care (target N = 64) in local federally-qualified health centers. Key eligibility criteria include self-identified NHB adults between ages 35-75 with a mean systolic blood pressure ≥ 130 mm/Hg obtained from 24-h ambulatory blood pressure monitoring. The FoRKS+ program includes 5 weeks of hypertension self-management courses, 11 weeks of nutrition courses, and 12 weeks of aerobic training in dietitian and health coach-led virtual groups. We will collect data on primary cognitive outcomes, feasibility, hypothesized intervention mediators and moderators, and demographic and health covariates at baseline, near intervention weeks 16-, and 28 (primary outcome assessment), and week 52 follow-up. We will use mixed-effects modeling to examine intervention effects on cognition. DISCUSSION: This pilot RCT will examine the feasibility and preliminary effects of a multicomponent lifestyle intervention on cognitive function in NHB adults, which may have implications for reducing health disparities in ADRD.

The influence of social and environmental determinants of health on hospitalizations for pediatric asthma.

BACKGROUND: Asthma is the most common chronic disease of childhood, and has several social, environmental, and demographic factors potentially influential to its disease burden. This study sought to determine the influence of these factors on hospital admissions and readmissions for pediatric asthma. METHODS: This was a retrospective cohort study using data from the Indiana Network for Patient Care, a state-wide health information exchange in the United States. Study participants were children 2-18 years old admitted to the hospital with a respiratory diagnostic code between 2010 and 2021. Clinical variables were obtained from electronic health record data, and social and environmental determinants of health data were obtained from the Indiana Social Assets and Vulnerabilities Indicators using geocoding systems. Negative binomial models were used to examine community level social and environmental risk factors modifying the relationship between patient characteristics and the risk of asthma-related hospitalizations and 30-day readmissions. RESULTS: The study sample included 25,063 patients with an average follow-up of 9 (SD = 5) years. Of these, there were 17,816 asthma-related admissions. There were a total of 1,037 asthma-related 30-day readmissions, with an incidence rate of readmissions relative to total visits of 0.028 per person-year. A high social vulnerability index (SVI) was associated with an increased rate of hospital admissions (Proportion attributable ratio: 1.09, 95%CI (1.03,1.15), p < 0.05). No environmental determinants of health were significantly associated with hospitalization rate. CONCLUSION: High SVI was significantly associated with increased risk of total hospital admissions for pediatric asthma.

Associations between outpatient treatment and the use of intensive psychiatric healthcare services.

The current manuscript examines concurrent and longitudinal associations between the utilization of outpatient and intensive psychiatric services among Medicaid-enrolled youth. Using an administrative dataset of Medicaid claims from 2007 to 2017, youth were included if they were between the ages of 10-18 (M = 13.4, SD = 2.6) and had a psychiatric Medicaid claim (N = 33,590). Psychiatric services were coded as outpatient, emergency department (ED), inpatient, or residential based on Medicaid codes. Logistic regression analyses indicated that the receipt of even one outpatient visit significantly reduced the odds of having an ED, inpatient, and residential visit within 60-, 90-, and 120-day windows. Survival analyses indicated most youth did not have any ED, inpatient, or residential visit following their first outpatient visit. For remaining youth, having an outpatient visit significantly increased the risk of having an ED, inpatient, and residential visit following their initial appointment, which may suggest these youth are being triaged to a more appropriate level of care. Classification accuracy analyses indicated a cutoff of 2 outpatient visits yielded maximum accuracy in determining youth with ED, inpatient, and residential visits. Findings highlight use of outpatient-level services in reducing risk of more intensive service utilization.

Age-specific rates of hospital transfers in long-stay nursing home residents.

INTRODUCTION: 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.

NIH Funding, Research Productivity, and Scientific Impact: a 20-Year Study.

BACKGROUND: The Research Project Grant (R01) is the oldest grant mechanism used by the National Institutes of Health (NIH). Receiving an R01 award is often taken as a sign of scientific success. We presented normative data on multiple productivity and impact metrics for a more objective assessment of funded grants' scientific success. METHODS: All initial R01 grants awarded by NIH in the year 2000 were prospectively followed and evaluated using the numbers of publications and citations, as well as the h-indices at the grant level. We examined the variability, time trends, and relations among these metrics to better understand the funded projects' cumulative output and impact. RESULTS: In the 20 years since initial funding, 4451 R01 grants generated a total of 55,053 publications. These publications were cumulatively cited 3,705,553 times over 736,811 citation years. The median number of publications was 8 (25th, 75th percentiles 4, 17) per grant for the entire 20-year duration. The median number of citations and the median h-index were 441 (25th, 75th percentiles 156, 1061) and 7 (25th, 75th percentiles 4, 13) per grant, respectively. The time courses of publication, citation, and accumulation of h-index were highly variable among the awarded grants. Although the metrics were correlated within an award, they reflected the grant's success in different domains. CONCLUSION: Numbers of publications, citations, and h-indices vary greatly among funded R01 grants. When used together, these metrics provide a more complete picture of the productivity and long-term impact of a funded grant.

Facility and resident characteristics associated with variation in nursing home transfers: evidence from the OPTIMISTIC demonstration project.

BACKGROUND: Centers for Medicare and Medicaid Services (CMS) funded demonstration project to evaluate financial incentives for nursing facilities providing care for 6 clinical conditions to reduce potentially avoidable hospitalizations (PAHs). The Optimizing Patient Transfers, Impacting Medical Quality, and Improving Symptoms: Transforming Institutional Care (OPTIMISTIC) site tested payment incentives alone and in combination with the successful nurse-led OPTIMISTIC clinical model. Our objective was to identify facility and resident characteristics associated with transfers, including financial incentives with or without the clinical model. METHODS: This was a longitudinal analysis from April 2017 to June 2018 of transfers among nursing home residents in 40 nursing facilities, 17 had the full clinical + payment model (1726 residents) and 23 had payment only model (2142 residents). Using CMS claims data, the Minimum Data Set, and Nursing Home Compare, multilevel logit models estimated the likelihood of all-cause transfers and PAHs (based on CMS claims data and ICD-codes) associated with facility and resident characteristics. RESULTS: The clinical + payment model was associated with 4.1 percentage points (pps) lower risk of all-cause transfers (95% confidence interval [CI] - 6.2 to - 2.1). Characteristics associated with lower PAH risk included residents aged 95+ years (- 2.4 pps; 95% CI - 3.8 to - 1.1), Medicare-Medicaid dual-eligibility (- 2.5 pps; 95% CI - 3.3 to - 1.7), advanced and moderate cognitive impairment (- 3.3 pps; 95% CI - 4.4 to - 2.1; - 1.2 pps; 95% CI - 2.2 to - 0.2). Changes in Health, End-stage disease and Symptoms and Signs (CHESS) score above most stable (CHESS score 4) increased the risk of PAH by 7.3 pps (95% CI 1.5 to 13.1). CONCLUSIONS: Multiple resident and facility characteristics are associated with transfers. Facilities with the clinical + payment model demonstrated lower risk of all-cause transfers compared to those with payment only, but not for PAHs.

Learning Hamiltonian Monte Carlo in R.

Hamiltonian Monte Carlo (HMC) is a powerful tool for Bayesian computation. In comparison with the traditional Metropolis-Hastings algorithm, HMC offers greater computational efficiency, especially in higher dimensional or more complex modeling situations. To most statisticians, however, the idea of HMC comes from a less familiar origin, one that is based on the theory of classical mechanics. Its implementation, either through Stan or one of its derivative programs, can appear opaque to beginners. A lack of understanding of the inner working of HMC, in our opinion, has hindered its application to a broader range of statistical problems. In this article, we review the basic concepts of HMC in a language that is more familiar to statisticians, and we describe an HMC implementation in R, one of the most frequently used statistical software environments. We also present hmclearn, an R package for learning HMC. This package contains a general-purpose HMC function for data analysis. We illustrate the use of this package in common statistical models. In doing so, we hope to promote this powerful computational tool for wider use. Example code for common statistical models is presented as supplementary material for online publication.

Context-Sensitive Ecological Momentary Assessment: Application of User-Centered Design for Improving User Satisfaction and Engagement During Self-Report.

BACKGROUND: Ecological momentary assessment (EMA) can be a useful tool for collecting real-time behavioral data in studies of health and health behavior. However, EMA administered through mobile technology can be burdensome, and it tends to suffer from suboptimal user engagement, particularly in low health-literacy populations. OBJECTIVE: This study aimed to report a case study involving the design and evaluation of a mobile EMA tool that supports context-sensitive EMA-reporting of location and social situations accompanying eating and sedentary behavior. METHODS: An iterative, user-centered design process with obese, middle-aged women seeking care in a safety-net health system was used to identify the preferred format of self-report measures and the look, feel, and interaction of the mobile EMA tool. A single-arm feasibility field trial with 21 participants receiving 12 prompts each day for momentary self-reports over a 4-week period (336 total prompts per participant) was used to determine user satisfaction with interface quality and user engagement, operationalized as response rate. A second trial among 38 different participants randomized to receive or not to receive a feature designed to improve engagement was conducted. RESULTS: The feasibility trial results showed high interface satisfaction and engagement, with an average response rate of 50% over 4 weeks. Qualitative feedback pointed to the need for auditory alerts. We settled on 3 alerts at 10-min intervals to accompany each EMA-reporting prompt. The second trial testing this feature showed a statistically significant increase in the response rate between participants randomized to receive repeat auditory alerts versus those who were not (60% vs 40%). CONCLUSIONS: This paper reviews the design research and a set of design constraints that may be considered in the creation of mobile EMA interfaces personalized to users' preferences. Novel aspects of the study include the involvement of low health-literacy adults in design research, the capture of data on time, place, and social context of eating and sedentary behavior, and reporting prompts tailored to an individual's location and schedule. TRIAL REGISTRATION: ClinicalTrials.gov NCT03083964; https://clinicaltrials.gov/ct2/show/NCT03083964.

The Sexual Health Needs of Adolescent Boys Involved in a Pregnancy.

PURPOSE: Little is known about fatherhood in middle adolescence. To better understand their sexual health needs, we describe relationship characteristics, perception of masculinity, and associated sexually transmitted infection (STI) risk behaviors in a community-based sample of urban middle adolescent boys who have fathered a child or been involved with a pregnancy. METHODS: We used venue-based sampling to recruit 339 boys (aged 14-17 years) in neighborhoods with high STI prevalence. We administered a brief survey on sexual relationship and pregnancy history, STI risk, juvenile justice involvement, and masculinity. RESULTS: Fifteen percent had either fathered a child or been involved with a pregnancy. In multivariate analysis, controlling for age and ethnicity, adolescent fathers were more likely to be involved with juvenile justice and engage in STI risk behaviors. These included condom nonuse and partner checking a cell phone. Although of borderline significance, older partners, past STI testing, and drug or alcohol use at last sex improved model fit. CONCLUSION: Adolescent fathers have distinct relational and sexual health needs. Their specific needs should be targeted by prevention programs.

Medicaid Coverage and Continuity for Juvenile Justice-Involved Youth.

This study examined Medicaid coverage and continuity for youth with varying levels of justice system involvement and the impact of a policy change allowing Medicaid suspension, rather than termination. Data for this study were collected using a retrospective cohort design using arrest records and Medicaid enrollment tables for 20,688 youth. Age, gender, race/ethnicity, and deepest level of justice system involvement all were associated with time to de-enrollment from Medicaid. Suspension was associated with a small improvement in Medicaid continuity for justice-involved youth. In addition, youth with deeper levels of justice system involvement had faster time to de-enrollment. This study highlights the importance of maximizing opportunities to keep youth enrolled, as gaps in coverage will likely affect juveniles' access to physical, mental, and behavioral health care.

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.

BACKGROUND: 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 APP-Me. 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.

Preventive Care Use Among Justice-Involved and Non-Justice-Involved Youth.

BACKGROUND AND OBJECTIVES: Youth involved in the juvenile justice system (ie, arrested youth) are at risk for health problems. Although increasing preventive care use by justice-involved youth (JIY) is 1 approach to improving their well-being, little is known about their access to and use of care. The objective of this study was to determine how rates of well-child (WC) and emergency department visits, as well as public insurance enrollment continuity, differed between youth involved in the justice system and youth who have never been in the system. We hypothesized that JIY would exhibit less frequent WC and more frequent emergency service use than non-justice-involved youth (NJIY). METHODS: This was a retrospective cohort study of administrative medical and criminal records of all youth (ages 12-18) enrolled in Medicaid in Marion County, Indiana, between January 1, 2004, and December 31, 2011. RESULTS: The sample included 88 647 youth; 20 668 (23%) were involved in the justice system. JIY had lower use rates of WC visits and higher use rates of emergency services in comparison with NJIY. JIY had more and longer gaps in Medicaid coverage compared with NJIY. For all youth sampled, both preventive and emergency services use varied significantly by Medicaid enrollment continuity. CONCLUSIONS: JIY experience more and longer gaps in Medicaid coverage, and rely more on emergency services than NJIY. Medicaid enrollment continuity was associated with differences in WC and emergency service use among JIY, with policy implications for improving preventive care for these vulnerable youth.

Varying Influences of Aldosterone on the Plasma Potassium Concentration in Blacks and Whites.

BACKGROUND: Aldosterone acts to restrain the extracellular potassium (K+) concentration. Blacks have on average lower plasma aldosterone concentrations (PACs) than Whites. Whether this ethnic difference is associated with similar changes in the concentration of K+ is unclear. METHODS: Subjects were Blacks and Whites from an observational study of blood pressure regulation. PAC was known to be significantly lower in Blacks than Whites. We sought to test the hypothesis that the concentration of K+ remains constant despite variability in PAC. Initial enrollment took place in childhood in 1986. Some of the original enrollees were studied again in adulthood: 160 healthy Blacks and 271 healthy Whites (ages 5 to 39 years; all were studied as children and as adults). RESULTS: Plasma renin activity [a biomarker of angiotensin II and, more proximally, extracellular fluid volume (ECFV)] and PAC were lower in Blacks (P < 0.0354 and P < 0.001, respectively, for all ages). At the same time no ethnic difference in levels of K+ was observed regardless of age. Plasma K+ concentration and PAC associated differently based on ethnicity: PAC increased in Blacks by 1.5-2.0 and in Whites by 2.3-3.0 ng/dl per mmol/l increase in K+ (P < 0.001). CONCLUSIONS: Lower aldosterone levels in Blacks did not translate into higher K+ concentrations. We speculate that reaching the right concentration of K+ was an endpoint of aldosterone production in the presence of varying levels of ECFV and angiotensin II.

Variation in Hospice Services by Location of Care: Nursing Home Versus Assisted Living Facility Versus Home.

OBJECTIVES: To describe differences in hospice services for patients living at home, in nursing homes or in assisted living facilities, including the overall number and duration of visits by different hospice care providers across varying lengths of stay. DESIGN: Retrospective cohort study using hospice patient electronic medical record data. SETTING: Large, national hospice provider. PARTICIPANTS: Data from 32,605 hospice patients who received routine hospice care from 2009 to 2014 were analyzed. MEASUREMENTS: Descriptive statistics were calculated for utilization measures for each type of provider and by location of care. Frequency and duration of service contacts were standardized to a 1 week period and pairwise comparisons were used to detect differences in care provided between the three settings. RESULTS: Minimal differences were found in overall intensity of service contacts across settings, however, the mix of services were different for patients living at home versus nursing home versus assisted living facility. Overall, more nurse care was provided at the beginning and end of the hospice episode; intensity of aide care services was higher in the middle portion of the hospice episode. Nearly 43% of the sample had hospice stays less than 2 weeks and up to 20% had stays greater than 6 months. CONCLUSION: There are significant differences between characteristics of hospice patients in different settings, as well as the mix of services they receive. Medicare hospice payment methodology was revised starting in 2016. While the new payment structure is in greater alignment with the U shape distribution of services, it will be important to evaluate the impact of the new payment methodology on length of stay and mix of services by different providers across settings of care.

Effect of Hospice Use on Costs of Care for Long-Stay Nursing Home Decedents.

OBJECTIVES: To analyze the costs for long-stay (>90 days) nursing home (NH) decedents with and without hospice care. DESIGN: Retrospective cohort study using a 1999-2009 data set of linked Medicare and Medicaid claims and minimum data set (MDS) assessments. SETTING: Indiana NHs. PARTICIPANTS: Long-stay NH decedents (N = 2,510). MEASUREMENTS: Medicare costs were calculated for 2, 7, 14, 30, 90, and 180 days before death; Medicaid costs were calculated for dual-eligible beneficiaries. Total costs and costs for hospice, NH, and inpatient care are reported. RESULTS: Of 2,510 long-stay NH decedents, 35% received hospice. Mean length of hospice was 103 days (median 34 days). Hospice users were more likely to have cancer (P < .001), a do-not-resuscitate order in place (P < .001), greater cognitive impairment (P < .001), and worse activity of daily living (ADL) function (P < .001) and less likely to have had a hospitalization in the year before death (P < .001). In propensity score analyses, hospice users had lower total Medicare costs for all time periods up to and including 90 days before death. For dually eligible beneficiaries, overall costs and Medicare costs were significantly lower for hospice users up to 30 days before death. Medicaid costs were not different between the groups except for the 2-day time period. CONCLUSION: In this analysis of costs to Medicare and Medicaid for long-stay NH decedents, use of hospice did not increase costs in the last 6 months of life. Evidence supporting cost savings is sensitive to analyses that vary the time period before death.

Self-Reported Medication Adherence Barriers Among Ambulatory Older Adults with Mild Cognitive Impairment.

STUDY OBJECTIVE: To compare the frequencies of barriers to medication adherence reported by ambulatory older adults with a diagnosis of mild cognitive impairment (MCI) and ambulatory older adults with normal cognition. DESIGN: Cross-sectional study. SETTING: Outpatient clinics within a safety-net health care system. PARTICIPANTS: Ambulatory older adults (≥ 65 yrs) with a diagnosis of MCI (96 participants) or normal cognition (104 participants). MEASUREMENTS AND MAIN RESULTS: Self-reported beliefs and barriers to medication nonadherence were assessed by items from the Morisky Medication Adherence Survey, the Adherence Estimator, and barriers derived from a systematic review of studies in older adults with cognitive impairment. Participants with a diagnosis of MCI had a mean age of 72 years, 77% were female, and 37% were African-American. Participants with normal cognition had a mean age of 76 years, 79% were female, and 47% were African-American. Among all participants, 83% reported the presence of at least one barrier to medication adherence, and 62.5% reported two or more barriers to medication adherence. The most commonly reported barriers were difficulty remembering the amount or time of each medication to take (49%), difficulty opening or reading prescription bottles (42%), feeling worse when taking medications (29%), and trouble affording medications (26%). Considering the multiple comparisons made in this analysis, few significant differences in barrier frequencies were identified between the groups with MCI and normal cognition. CONCLUSION: Multiple medication adherence barriers were identified among all participants, including cognitive, physical, and financial barriers, although few significant differences were identified between those with and without MCI. Interventions capable of addressing multiple barriers are required to improve medication adherence in older adults with and without MCI.

Robust nonparametric estimation of monotone regression functions with interval-censored observations.

Nonparametric estimation of monotone regression functions is a classical problem of practical importance. Robust estimation of monotone regression functions in situations involving interval-censored data is a challenging yet unresolved problem. Herein, we propose a nonparametric estimation method based on the principle of isotonic regression. Using empirical process theory, we show that the proposed estimator is asymptotically consistent under a specific metric. We further conduct a simulation study to evaluate the performance of the estimator in finite sample situations. As an illustration, we use the proposed method to estimate the mean body weight functions in a group of adolescents after they reach pubertal growth spurt.

Mortality of Youth Offenders Along a Continuum of Justice System Involvement.

INTRODUCTION: Black male youth are at high risk of homicide and criminal justice involvement. This study aimed to determine how early mortality among youth offenders varies based on race; gender; and the continuum of justice system involvement: arrest, detention, incarceration, and transfer to adult courts. METHODS: Criminal and death records of 49,479 youth offenders (ages 10-18 years at first arrest) in Marion County, Indiana, from January 1, 1999, to December 31, 2011, were examined. Statistical analyses were completed in November 2014. RESULTS: From 1999 to 2011 (aggregate exposure, 386,709 person-years), 518 youth offender deaths occurred. The most common cause of death was homicide (48.2%). The mortality rate of youth offenders was nearly 1.5 times greater than that among community youth (standardized mortality ratio, 1.48). The youth offender mortality rate varied depending on the severity of justice system involvement. Arrested youth had the lowest rate of mortality (90/100,000), followed by detained youth (165/100,000); incarcerated youth (216/100,000); and youth transferred to adult court (313/100,000). A proportional hazards model demonstrated that older age, male gender, and more severe justice system involvement 5 years post-arrest predicted shorter time to mortality. CONCLUSIONS: Youth offenders face greater risk for early death than community youth. Among these, black male youth face higher risk of early mortality than their white male counterparts. However, regardless of race/ethnicity, mortality rates for youth offenders increase as youth involvement in the justice system becomes more protracted and severe. Thus, justice system involvement is a significant factor to target for intervention.

Age Differences in the Association Between Body Mass Index Class and Annualized Medicare Expenditures.

OBJECTIVE: 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.

Optimizing strategies for population-based chlamydia infection screening among young women: an age-structured system dynamics approach.

BACKGROUND: Chlamydia infection (CT) is one of the most commonly reported sexually transmitted diseases. It is often referred to as a "silent" disease with the majority of infected people having no symptoms. Without early detection, it can progress to serious reproductive and other health problems. Economical identification of asymptomatically infected is a key public health challenge. Increasing evidence suggests that CT infection risk varies over the range of adolescence. Hence, age-dependent screening strategies with more frequent testing for certain age groups of higher risk may be cost-saving in controlling the disease. METHODS: We study the optimization of age-dependent screening strategies for population-based chlamydia infection screening among young women. We develop an age-structured compartment model for CT natural progress, screening, and treatment. We apply parameter optimization on the resultant PDE-based system dynamical models with the objective of minimizing the total care spending, including screening and treatment costs during the program period and anticipated costs of treating the sequelae afterwards). For ease of practical implementation, we also search for the best screening initiation age for strategies with a constant screening frequency. RESULTS: The optimal age-dependent strategies identified outperform the current CDC recommendations both in terms of total care spending and disease prevalence at the termination of the program. For example, the age-dependent strategy that allows monthly screening rate changes can save about 5% of the total spending. Our results suggest early initiation of CT screening is likely beneficial to the cost saving and prevalence reduction. Finally, our results imply that the strategy design may not be sensitive to accurate quantification of the age-specific CT infection risk if screening initiation age and screening rate are the only decisions to make. CONCLUSIONS: Our research demonstrates the potential economic benefit of age-dependent screening strategy design for population-based screening programs. It also showcases the applicability of age-structured system dynamical modeling to infectious disease control with increasing evidence on the age differences in infection risk. The research can be further improved with consideration of the difference between first-time infection and reinfection, as well as population heterogeneity in sexual partnership.