Implications of Delayed Testosterone Recovery in Patients with Prostate Cancer

To assess the clinical impact of delayed testosterone recovery (TR) following the discontinuation of medical androgen deprivation therapy (ADT), a retrospective, longitudinal analysis was conducted in adult males with prostate cancer using the Optum® de-identified Electronic Health Record data set and Optum® Enriched Oncology Data (2010-2021). Of 3875 patients who initiated and discontinued ADT, 1553 received one or more testosterone-level tests within the 12 mo following discontinuation and were included in this study. These 1553 patients were categorized into two cohorts: 25% as TR (testosterone levels >280 ng/dl at any test within 12 mo following ADT discontinuation) and 75% as non-TR. At baseline, non-TR patients were older, had lower testosterone levels, and were more likely to have diabetes, hyperlipidemia, and hypertension, but less likely to have sexual dysfunction. After adjustment for baseline characteristics, the TR cohort had a lower risk of new-onset diabetes (hazard ratio [HR] 0.47; 95% confidence interval [CI] 0.27-0.79), trended toward a lower risk of new-onset depression (HR 0.58; 95% CI 0.33-1.02), and had a higher likelihood of seeking treatment for sexual dysfunction (HR 1.33; 95% CI 0.99-1.78) versus the non-TR cohort. These findings support monitoring testosterone levels after ADT discontinuation to manage potential long-term comorbidities in patients with prostate cancer.

Patient summary

This real-world analysis of males with prostate cancer who were treated with medical androgen deprivation therapy (ADT) found that most patients did not have their testosterone level checked in the 12 mo after stopping ADT. Of those who did, 75% did not achieve normal testosterone levels (>280 ng/dl), and these patients were more likely to experience new-onset diabetes than those who achieved normal testosterone levels. These results suggest that to ensure effective clinical decision-making, physicians should check patients' testosterone levels after stopping ADT.

Disease progression rates in ambulatory Duchenne muscular dystrophy by steroid type, patient age and functional status

Aim: To examine benefits of corticosteroids for Duchenne muscular dystrophy (DMD) by age and disease progression. Methods: Data from daily steroid users (placebo-treated) were pooled from four phase 2b/3 trials in DMD. Outcomes assessed overall and among subgroups included changes from baseline to 48 weeks in six-minute walk distance (6MWD), timed function tests and North Star Ambulatory Assessment total score. Results: Among 231 patients receiving deflazacort (n = 127) or prednisone (n = 104), observed differences in 6MWD favoring deflazacort over prednisone were significant for patients with relatively older age (≥8-years-old), greater disease progression (baseline timed stand from supine ≥5 s), or longer corticosteroid use (>3 years). Conclusion: Daily deflazacort had greater benefits than daily prednisone particularly among older/more progressed patients.

Health Care Resource Utilization by Patients with Alagille Syndrome

OBJECTIVE

To assess and characterize health care resource utilization (HRU) in children with the rare, genetic, multisystem disorder, Alagille syndrome.

STUDY DESIGN

This retrospective analysis reviewed commercially insured and Medicaid-insured claims from October 1, 2015 to December 31, 2019 to assess HRU in patients with Alagille syndrome. As there is no specific International Classification ofDiseases-10 code for Alagille syndrome, patients were identified using the following algorithm: ≥1 claim with diagnosis code Q44.7 (other congenital malformations of the liver); <18 years of age, with no history of biliary atresia (International Classification ofDiseases-10 code: Q44.2); and ≥6 months of insurance eligibility prior to diagnosis. HRU was summarized per patient per year over all available claims postdiagnosis.

RESULTS

A total of 171 commercially insured and 215 Medicaid-insured patients with Alagille syndrome were available for analysis. Annually, commercially insured and Medicaid-insured patients averaged 31 medical visits (range, 1.5-237) and 48 medical visits (range, 0.7-690), respectively. The most common visits were outpatient with the majority encompassing lab/imaging and primary care visits (commercially insured: 21 [range, 0.0-183]; Medicaid-insured: 26 [range, 0.0-609]). Inpatient visits were the highest driver of costs in both the commercial and Medicaid populations.

CONCLUSIONS

Patients with Alagille syndrome have a substantial HRU burden driven largely by numerous outpatient visits and costly inpatient stays. Given the complexity and variability of Alagille syndrome presentation, patients may benefit from multidisciplinary and subspecialized care.

Functional and Clinical Outcomes Associated with Steroid Treatment among Non-ambulatory Patients with Duchenne Muscular Dystrophy1

BACKGROUND

Evidence on the long-term efficacy of steroids in Duchenne muscular dystrophy (DMD) after loss of ambulation is limited.

OBJECTIVE

Characterize and compare disease progression by steroid treatment (prednisone, deflazacort, or no steroids) among non-ambulatory boys with DMD.

METHODS

Disease progression was measured by functional status (Performance of Upper Limb Module for DMD 1.2 [PUL] and Egen Klassifikation Scale Version 2 [EK] scale) and by cardiac and pulmonary function (left ventricular ejection fraction [LVEF], forced vital capacity [FVC] % -predicted, cough peak flow [CPF]). Longitudinal changes in outcomes, progression to key disease milestones, and dosing and body composition metrics were analyzed descriptively and in multivariate models.

RESULTS

This longitudinal cohort study included 86 non-ambulatory patients with DMD (mean age 13.4 years; n = 40 [deflazacort], n = 29 [prednisone], n = 17 [no steroids]). Deflazacort use resulted in slower average declines in FVC % -predicted vs. no steroids (+3.73 percentage points/year, p < 0.05). Both steroids were associated with significantly slower average declines in LVEF, improvement in CPF, and slower declines in total PUL score and EK total score vs. no steroids; deflazacort was associated with slower declines in total PUL score vs. prednisone (all p < 0.05). Both steroids also preserved functional abilities considered especially important to quality of life, including the abilities to perform hand-to-mouth function and to turn in bed at night unaided (all p < 0.05 vs. no steroids).

CONCLUSIONS

Steroid use after loss of ambulation in DMD was associated with delayed progression of important pulmonary, cardiac, and upper extremity functional deficits, suggesting some benefits of deflazacort over prednisone.

Burden of Illness and Treatment Patterns Among Patients With von Willebrand Disease in US Clinical Practice

In this retrospective cohort study, data from an integrated US healthcare system containing both electronic medical record data and linked claims data (from 01/2004 to 12/2020) were used to evaluate the clinical burden, treatment patterns, and healthcare resource use (HRU) in patients with von Willebrand disease (VWD). Two patient cohorts were analyzed: the overall VWD population (n  =  396) and a subset of these patients (n  =  75) who were considered potentially eligible for prophylaxis treatment with von Willebrand factor (VWF) based on a history of severe and frequent bleeding. HRU (hospitalizations, outpatient visits, and emergency department visits) were measured in patients with linked claims data (n  =  110, overall VWD patients; n  =  23 potentially VWF-prophylaxis-eligible VWD patients). In general, patients with VWD experienced a substantial burden of bleeding events, comorbidities, and HRU. Patients with VWD who were considered potentially eligible for prophylaxis owing to severe and frequent bleeds suffered from a higher clinical burden and HRU than the overall VWD population, and thus may benefit from VWF prophylactic treatment. The findings from this study could help improve clinical outcomes and manage HRU for patients with VWD.

Maralixibat Treatment Response in Alagille Syndrome is Associated with Improved Health-Related Quality of Life

OBJECTIVE

The objective of this study was to assess the impact of treatment response to the ileal bile acid transporter inhibitor maralixibat on health-related quality of life (HRQoL) in children with Alagille syndrome.

STUDY DESIGN

This analysis used data from the ICONIC trial, a phase 2 study with a 4-week double-blind, placebo-controlled, randomized drug withdrawal period in children with Alagille syndrome with moderate-to-severe pruritus. Clinically meaningful treatment response to maralixibat was defined a priori as a ≥1-point reduction in the Itch-Reported Outcome (Observer) score, from baseline to week 48. HRQoL was assessed using the Pediatric Quality of Life Inventory Generic Core, Family Impact, and Multidimensional Fatigue scale scores, which were collected via the caregiver. The minimal clinically important difference for HRQoL ranged from 4 to 5 points, depending on the scale.

RESULTS

Twenty of the 27 patients (74%) included in this analysis achieved an Itch-Reported Outcome (Observer) treatment response at week 48. The mean (SD) change in Multidimensional Fatigue score was +25.8 (23.0) for responders vs -3.1 (19.8) for nonresponders (P = .03). Smaller and non-statistically significant mean changes were observed for the Pediatric Quality of Life Inventory Generic Core and Family Impact scores. Controlling for baseline Family Impact score, responders' Family Impact scores increased an average of 16.9 points over 48 weeks compared with non-responders (P = .05). Smaller and non-statistically significant point estimates were observed for the Pediatric Quality of Life Inventory Generic Core and Multidimensional Fatigue scores.

CONCLUSION

The significant improvements in pruritus seen with maralixibat at week 48 of the ICONIC study are clinically meaningful and are associated with improved HRQoL.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02160782.

2145. Economic Burden of Congenital Cytomegalovirus Infection in Commercially- and Medicaid-insured Patients in the United States

Background

Congenital cytomegalovirus (cCMV) infection is the leading infectious cause of congenital birth defects. Approximately 20-25% of infants born with cCMV develop long-term health complications such as hearing loss, developmental issues, and microcephaly. Despite this, studies on the economic burden of cCMV are limited. The aim of this study is to assess the healthcare resource utilization (HRU) and cost burden among a sample of cCMV patients in the US using insurance claims data.

Methods

This retrospective study utilized IBM Watson Health MarketScan® Commercial Claims and Encounters and Multi-State Medicaid data from January 1, 2010 to December 31, 2019. Separately for each payer population, patients were included in the cCMV cohort if their first diagnosis (index date) of cCMV (ICD-9: 771.1; ICD-10: P35.1) or CMV (ICD-9: 78.5; ICD-10: B25.x) was within 1 month of birth. The index date for non-cCMV controls was selected at random from all medical claims within 1 month of birth. cCMV patients were matched 1:1 to controls on demographics, insurance type, birth year, and index year. All patients were required to have ≥ 1 year of continuous health plan enrollment post-index (study period). HRU and costs in 2021 USD ($) were summarized over the study period. Costs for birth admissions were also described.

Results

195 Commercial and 549 Medicaid matched pairs were included in the analyses. Mean ± SD age at first diagnosis was 8.4 ± 8.6 days and 5.9 ± 7.8 days for Commercial and Medicaid cases, respectively. Mean birth length of stay for Commercial and Medicaid cases was 24 days (vs. 5 for controls), with mean birth admission costs of $149,192 (vs. $17,996) and $49,885 (vs. $5,052), respectively. On average, cCMV patients had higher study period HRU and costs compared to controls (Table 1). Excess costs due to cCMV were estimated at $33,223 for Commercial and $9,748 for Medicaid.

Conclusion

cCMV patients have substantial HRU and costs during the 1-year post-diagnosis. While the majority of patients did not require hospitalization, inpatient care contributed substantially to the overall cost burden. Future studies should evaluate longer-term costs beyond the first year as well as the reasons underlying the high economic burden among cCMV patients.

Disclosures

John D. Diaz-Decaro, PhD, MS, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds Gail J. Demmler-Harrison, MD, Elsevier: Book royalties|Merck: Grant/Research Support|Microgen: Advisor/Consultant|Microgen: Grant/Research Support|Moderna: Advisor/Consultant|UpToDate Wolters Kluwer Health: Royalties Jessica R. Marden, ScD, MPH, Moderna, Inc.: Advisor/Consultant Annika Anderson, MPH, Moderna, Inc.: Advisor/Consultant Sandeep Basnet, MD, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds Katherine Gaburo, n/a, Moderna, Inc.: Advisor/Consultant Danielle Peterson, n/a, Moderna, Inc.: Advisor/Consultant Kosuke Kawai, ScD, MS, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds Noam Kirson, PhD, Moderna, Inc.: Advisor/Consultant Urvi Desai, PhD, Moderna, Inc.: Advisor/Consultant Philip Buck, PhD, MPH, Moderna, Inc.: Salary|Moderna, Inc.: Stocks/Bonds.

The Economic Burden of Schizophrenia in the United States

Aim: The economic burden of schizophrenia in the United States (US) was estimated at $155.7 billion in 2013. Since 2013, the US experienced significant health care reforms and treatment advances. This study analyzed recent data and literature to update the US economic burden estimate for schizophrenia. Methods: Direct and indirect costs associated with schizophrenia were estimated using a prevalence-based approach. Direct health care costs were assessed retrospectively using an exact matched cohort design in the IBM Watson Health MarketScan databases from October 1, 2015, through December 31, 2019. Patients with schizophrenia (identified using ICD-10-CM codes F20 and F25) were exactly matched to controls on demographics, insurance type, and index year. Direct non-health care costs were estimated using published literature and government data. Indirect costs were estimated using a human capital approach and the value of quality-adjusted life-years lost. Cost offsets were estimated to account for basic living costs avoided. Excess costs, comparing costs for individuals with and without schizophrenia, were reported in 2019 USD. Results: The estimated excess economic burden of schizophrenia in the US in 2019 was $343.2 billion, including $251.9 billion in indirect costs (73.4%), $62.3 billion in direct health care costs (18.2%), and $35.0 billion in direct non-health care costs (10.2%). The largest drivers of indirect costs were caregiving ($112.3 billion), premature mortality ($77.9 billion), and unemployment ($54.2 billion). Cost offsets, representing $6.0 billion (1.7%), were subtracted from direct non-health care costs. Conclusions: The estimated burden of schizophrenia in the US doubled between 2013 and 2019 and was $343.2 billion in 2019, highlighting the importance of effective strategies and treatment options to improve the management of this difficult-to-treat patient population.

Impact of the COVID-19 pandemic on adolescent vaccinations: projected time to reverse deficits in routine adolescent vaccination in the United States

OBJECTIVE

The COVID-19 pandemic has led to significant reductions in the administration of routinely recommended vaccines among adolescents in the US including tetanus, diphtheria, and acellular pertussis (Tdap); meningococcal (ACWY); and human papillomavirus (HPV) vaccines. The extent to which these deficits could persist in 2021 and beyond is unclear. To address this knowledge gap, this study estimated the cumulative deficits of routine vaccine doses among US adolescents during the COVID-19 pandemic and estimated the time and effort needed to recover from those deficits.

METHODS

Monthly reductions in Tdap, meningococcal, and HPV doses administered to US adolescents during the COVID-19 pandemic were quantified using MarketScan Commercial Claims and Encounters data. The time and effort required to reverse the vaccination deficit under various catch-up scenarios were estimated.

RESULTS

Annual doses administered of Tdap, meningococcus, and HPV vaccines decreased by 21.2%, 20.8%, and 24.0%, respectively, in 2020 compared to 2019. For 2021, the reduction in doses administered is projected to be 6%-21% compared to 2019 under different scenarios. The projected deficit of missed doses is expected to be cleared between winter 2023 and fall 2031.

CONCLUSIONS

Administration rates of routine vaccines decreased significantly among US adolescents during COVID-19. Reversing these deficits to mitigate long-term health and economic consequences will require a sustained increase in vaccination rates over multiple years.

Steroid switching in dystrophinopathy treatment: a US chart review of patient characteristics and clinical outcomes

Aim: To describe reasons for switching from prednisone/prednisolone to deflazacort and associated clinical outcomes among patients with Duchenne and Becker muscular dystrophy (DMD and BMD, respectively) in the USA. Methods: A chart review of patients with DMD (n = 62) or BMD (n = 30) who switched from prednisone to deflazacort (02/2017-12/2018) collected demographic/clinical characteristics, reasons for switching, outcomes and common adverse events. Results: The mean ages at switch were 20.1 (DMD) and 9.2 (BMD) years. The primary physician-reported reasons for switching were 'to slow disease progression' (DMD: 83%, BMD: 79%) and 'tolerability' (67 and 47%). Switching was 'very' or 'somewhat' effective at addressing the primary reasons in 90-95% of patients. Conclusion: Physician-reported outcomes were consistent with deflazacort addressing patients' primary reasons for switching.

Real-world outcomes of long-term prednisone and deflazacort use in patients with Duchenne muscular dystrophy: experience at a single, large care center

Aim: To assess outcomes among patients with Duchenne muscular dystrophy receiving deflazacort or prednisone in real-world practice. Methods: Clinical data for 435 boys with Duchenne muscular dystrophy from Cincinnati Children’s Hospital Medical Center were studied retrospectively using time-to-event and regression analyses. Results: Median ages at loss of ambulation were 15.6 and 13.5 years among deflazacort- and prednisone-initiated patients, respectively. Deflazacort was also associated with a lower risk of scoliosis and better ambulatory function, greater % lean body mass, shorter stature and lower weight, after adjusting for age and steroid duration. No differences were observed in whole body bone mineral density or left ventricular ejection fraction. Conclusion: This single center study adds to the real-world evidence associating deflazacort with improved clinical outcomes.

Mother's education and late-life disparities in memory and dementia risk among US military veterans and non-veterans

BACKGROUND

Adverse childhood socioeconomic status (cSES) predicts higher late-life risk of memory loss and dementia. Veterans of U.S. wars are eligible for educational and economic benefits that may offset cSES disadvantage. We test whether cSES disparities in late-life memory and dementia are smaller among veterans than non-veterans.

METHODS

Data came from US-born men in the 1995-2014 biennial surveys of the Health and Retirement Study (n=7916 born 1928-1956, contributing n=38 381 cognitive assessments). Childhood SES was represented by maternal education. Memory and dementia risk were assessed with brief neuropsychological assessments and proxy reports. Military service (veteran/non-veteran) was evaluated as a modifier of the effect of maternal education on memory and dementia risk. We employed linear or logistic regression models to test whether military service modified the effect of maternal education on memory or dementia risk, adjusted for age, race, birthplace and childhood health.

RESULTS

Low maternal education was associated with worse memory than high maternal education (β = -0.07 SD, 95% CI -0.08 to -0.05), while veterans had better memory than non-veterans (β = 0.03 SD, 95% CI 0.02 to 0.04). In interaction analyses, maternal education disparities in memory were smaller among veterans than non-veterans (difference in disparities = 0.04 SD, 95% CI 0.01 to 0.08, p = 0.006). Patterns were similar for dementia risk.

CONCLUSIONS

Disparities in memory by maternal education were smaller among veterans than non-veterans, suggesting military service and benefits partially offset the deleterious effects of low maternal education on late-life cognitive outcomes.

Implementation of Instrumental Variable Bounds for Data Missing Not at Random

Instrumental variables are routinely used to recover a consistent estimator of an exposure causal effect in the presence of unmeasured confounding. Instrumental variable approaches to account for nonignorable missing data also exist but are less familiar to epidemiologists. Like instrumental variables for exposure causal effects, instrumental variables for missing data rely on exclusion restriction and instrumental variable relevance assumptions. Yet these two conditions alone are insufficient for point identification. For estimation, researchers have invoked a third assumption, typically involving fairly restrictive parametric constraints. Inferences can be sensitive to these parametric assumptions, which are typically not empirically testable. The purpose of our article is to discuss another approach for leveraging a valid instrumental variable. Although the approach is insufficient for nonparametric identification, it can nonetheless provide informative inferences about the presence, direction, and magnitude of selection bias, without invoking a third untestable parametric assumption. An important contribution of this article is an Excel spreadsheet tool that can be used to obtain empirical evidence of selection bias and calculate bounds and corresponding Bayesian 95% credible intervals for a nonidentifiable population proportion. For illustrative purposes, we used the spreadsheet tool to analyze HIV prevalence data collected by the 2007 Zambia Demographic and Health Survey (DHS).

Contribution of Socioeconomic Status at 3 Life-Course Periods to Late-Life Memory Function and Decline: Early and Late Predictors of Dementia Risk

Both early life and adult socioeconomic status (SES) predict late-life level of memory; however, evidence is mixed on the relationship between SES and rate of memory decline. Further, the relative importance of different life-course periods for rate of late-life memory decline has not been evaluated. We examined associations between life-course SES and late-life memory function and decline. Health and Retirement Study participants (n = 10,781) were interviewed biennially from 1998-2012 (United States). SES measurements for childhood (composite score including parents' educational attainment), early adulthood (high-school or college completion), and older adulthood (income, mean age 66 years) were all dichotomized. Word-list memory was modeled via inverse-probability weighted longitudinal models accounting for differential attrition, survival, and time-varying confounding, with nonrespondents retained via proxy assessments. Compared to low SES at all 3 points (referent), stable, high SES predicted the best memory function and slowest decline. High-school completion had the largest estimated effect on memory (β = 0.19; 95% confidence interval: 0.15, 0.22), but high late-life income had the largest estimated benefit for slowing declines (for 10-year memory change, β = 0.35; 95% confidence interval: 0.24, 0.46). Both early and late-life interventions are potentially relevant for reducing dementia risk by improving memory function or slowing decline.

Alzheimer's disease genetic risk variants beyond APOE ε4 predict mortality

INTRODUCTION

We hypothesized that, like apolipoprotein E (APOE), other late-onset Alzheimer's disease (LOAD) genetic susceptibility loci predict mortality.

METHODS

We used a weighted genetic risk score (GRS) from 21 non-APOE LOAD risk variants to predict survival in the Adult Changes in Thought and the Health and Retirement Studies. We meta-analyzed hazard ratios and examined models adjusted for cognitive performance or limited to participants with dementia. For replication, we assessed the GRS-longevity association in the Cohorts for Heart and Aging Research in Genomic Epidemiology, comparing cases surviving to age ≥90 years with controls who died between ages 55 and 80 years.

RESULTS

Higher GRS predicted mortality (hazard ratio = 1.05; 95% confidence interval: 1.00-1.10, P = .04). After adjusting for cognitive performance or restricting to participants with dementia, the relationship was attenuated and no longer significant. In case-control analysis, the GRS was associated with reduced longevity (odds ratio = 0.64; 95% confidence interval: 0.41-1.00, P = .05).

DISCUSSION

Non-APOE LOAD susceptibility loci confer risk for mortality, likely through effects on dementia incidence.

Comparing Variability, Severity, and Persistence of Depressive Symptoms as Predictors of Future Stroke Risk

OBJECTIVE

Numerous studies show that depressive symptoms measured at a single assessment predict greater future stroke risk. Longer-term symptom patterns, such as variability across repeated measures or worst symptom level, might better reflect adverse aspects of depression than a single measurement. This prospective study compared five approaches to operationalizing depressive symptoms at annual assessments as predictors of stroke incidence.

DESIGN

Cohort followed for incident stroke over an average of 6.4 years.

SETTING

The Adult Changes in Thought cohort follows initially cognitively intact, community- dwelling older adults from a population base defined by membership in Group Health, a Seattle-based nonprofit healthcare organization.

PARTICIPANTS

3,524 individuals aged 65 years and older.

MEASUREMENTS

We identified 665 incident strokes using ICD codes. We considered both baseline Center for Epidemiologic Studies-Depression scale (CES-D) score and, using a moving window of three most recent annual CES-D measurements, we compared most recent, maximum, average, and intra-individual variability of CES-D scores as predictors of subsequent stroke using Cox proportional hazards models.

RESULTS

Greater maximum (hazard ratio [HR]: 1.18; 95% CI: 1.07-1.30), average (HR: 1.20; 95% CI: 1.05-1.36) and intra-individual variability (HR: 1.15; 95% CI: 1.06-1.24) in CES-D were each associated with elevated stroke risk, independent of sociodemographics, cardiovascular risks, cognition, and daily functioning. Neither baseline nor most recent CES-D was associated with stroke. In a combined model, intra-individual variability in CES-D predicted stroke, but average CES-D did not.

CONCLUSIONS

Capturing the dynamic nature of depression is relevant in assessing stroke risk. Fluctuating depressive symptoms may reflect a prodrome of reduced cerebrovascular integrity.

A Simulation Platform for Quantifying Survival Bias: An Application to Research on Determinants of Cognitive Decline

Bias due to selective mortality is a potential concern in many studies and is especially relevant in cognitive aging research because cognitive impairment strongly predicts subsequent mortality. Biased estimation of the effect of an exposure on rate of cognitive decline can occur when mortality is a common effect of exposure and an unmeasured determinant of cognitive decline and in similar settings. This potential is often represented as collider-stratification bias in directed acyclic graphs, but it is difficult to anticipate the magnitude of bias. In this paper, we present a flexible simulation platform with which to quantify the expected bias in longitudinal studies of determinants of cognitive decline. We evaluated potential survival bias in naive analyses under several selective survival scenarios, assuming that exposure had no effect on cognitive decline for anyone in the population. Compared with the situation with no collider bias, the magnitude of bias was higher when exposure and an unmeasured determinant of cognitive decline interacted on the hazard ratio scale to influence mortality or when both exposure and rate of cognitive decline influenced mortality. Bias was, as expected, larger in high-mortality situations. This simulation platform provides a flexible tool for evaluating biases in studies with high mortality, as is common in cognitive aging research.

African Ancestry, Social Factors, and Hypertension Among Non-Hispanic Blacks in the Health and Retirement Study

The biomedical literature contains much speculation about possible genetic explanations for the large and persistent black-white disparities in hypertension, but profound social inequalities are also hypothesized to contribute to this outcome. Our goal is to evaluate whether socioeconomic status (SES) differences provide a plausible mechanism for associations between African ancestry and hypertension in a U.S. cohort of older non-Hispanic blacks. We included only non-Hispanic black participants (N = 998) from the Health and Retirement Study who provided genetic data. We estimated percent African ancestry based on 84,075 independent single nucleotide polymorphisms using ADMIXTURE V1.23, imposing K = 4 ancestral populations, and categorized into quartiles. Hypertension status was self-reported in the year 2000. We used linear probability models (adjusted for age, sex, and southern birth) to predict prevalent hypertension with African ancestry quartile, before and after accounting for a small set of SES measures. Respondents with the highest quartile of African ancestry had 8 percentage points' (RD = 0.081; 95% CI: -0.001, 0.164) higher prevalence of hypertension compared to the lowest quartile. Adjustment for childhood disadvantage, education, income, and wealth explained over one-third (RD = 0.050; 95% CI: -0.034, 0.135) of the disparity. Explanations for the residual disparity remain unspecified and may include other indicators of SES or diet, lifestyle, and psychosocial mechanisms.

Do physical activity, smoking, drinking, or depression modify transitions from cognitive impairment to functional disability?

BACKGROUND

Individual-level modifiers can delay onset of limitations in basic activities of daily living (ADLs) among cognitively impaired individuals. We assessed whether these modifiers also delayed onset of limitations in instrumental ADLs (IADLs) among individuals at elevated dementia risk.

OBJECTIVES

To determine whether modifiable individual-level factors delay incident IADL limitations among adults stratified by dementia risk.

METHODS

Health and Retirement Study participants aged 65+ without activity limitations in 1998 or 2000 (n = 5,219) were interviewed biennially through 2010. Dementia probability, categorized in quartiles, was used to predict incident IADL limitations with Poisson regression. We estimated relative (risk ratio) and absolute (number of limitations) effects from models including dementia, individual-level modifiers (physical inactivity, smoking, no alcohol consumption, and depression) and interaction terms between dementia and individual-level modifiers.

RESULTS

Dementia probability quartile predicted incident IADL limitations (relative risk for highest versus lowest quartile = 0.44; 95% CI: 0.28-0.70). Most modifiers did not significantly increase risk of IADL limitations among the cognitively impaired. Physical inactivity (RR = 1.60; 95% CI: 1.16, 2.19) increased the risk of IADL limitations among the cognitively impaired. The interaction between physical inactivity and low dementia probability was statistically significant (p = 0.009) indicating that physical inactivity had significantly larger effects on incident IADLs among cognitively normal than among those with high dementia probability.

CONCLUSION

Physical activity may protect against IADL limitations while not smoking, alcohol consumption, and not being depressed do not afford substantial protection among the cognitively impaired. RESULTS highlight the need for extra support for IADLs among individuals with cognitive losses.

Changes in Depressive Symptoms and Incidence of First Stroke Among Middle-Aged and Older US Adults

Background

Although research has demonstrated that depressive symptoms predict stroke incidence, depressive symptoms are dynamic. It is unclear whether stroke risk persists if depressive symptoms remit.

Methods and Results

Health and Retirement Study participants (n=16 178, stroke free and noninstitutionalized at baseline) were interviewed biennially from 1998 to 2010. Stroke and depressive symptoms were assessed through self-report of doctors’ diagnoses and a modified Center for Epidemiologic Studies - Depression scale (high was ≥3 symptoms), respectively. We examined whether depressive symptom patterns, characterized across 2 successive interviews (stable low/no, onset, remitted, or stable high depressive symptoms) predicted incident stroke (1192 events) during the subsequent 2 years. We used marginal structural Cox proportional hazards models adjusted for demographics, health behaviors, chronic conditions, and attrition. We also estimated effects stratified by age (≥65 years), race or ethnicity (non-Hispanic white, non-Hispanic black, Hispanic), and sex. Stroke hazard was elevated among participants with stable high (adjusted hazard ratio 2.14, 95% CI 1.69 to 2.71) or remitted (adjusted hazard ratio 1.66, 95% CI 1.22 to 2.26) depressive symptoms compared with participants with stable low/no depressive symptoms. Stable high depressive symptom predicted stroke among all subgroups. Remitted depressive symptoms predicted increased stroke hazard among women (adjusted hazard ratio 1.86, 95% CI 1.30 to 2.66) and non-Hispanic white participants (adjusted hazard ratio 1.66, 95% CI 1.18 to 2.33) and was marginally associated among Hispanics (adjusted hazard ratio 2.36, 95% CI 0.98 to 5.67).

Conclusions

In this cohort, persistently high depressive symptoms were associated with increased stroke risk. Risk remained elevated even if depressive symptoms remitted over a 2-year period, suggesting cumulative etiologic mechanisms linking depression and stroke.

Validation of a polygenic risk score for dementia in black and white individuals

OBJECTIVE

To determine whether a polygenic risk score for Alzheimer's disease (AD) predicts dementia probability and memory functioning in non-Hispanic black (NHB) and non-Hispanic white (NHW) participants from a sample not used in previous genome-wide association studies.

METHODS

Non-Hispanic white and NHB Health and Retirement Study (HRS) participants provided genetic information and either a composite memory score (n = 10,401) or a dementia probability score (n = 7690). Dementia probability score was estimated for participants' age 65+ from 2006 to 2010, while memory score was available for participants age 50+. We calculated AD genetic risk scores (AD-GRS) based on 10 polymorphisms confirmed to predict AD, weighting alleles by beta coefficients reported in AlzGene meta-analyses. We used pooled logistic regression to estimate the association of the AD-GRS with dementia probability and generalized linear models to estimate its effect on memory score.

RESULTS

Each 0.10 unit change in the AD-GRS was associated with larger relative effects on dementia among NHW aged 65+ (OR = 2.22; 95% CI: 1.79, 2.74; P < 0.001) than NHB (OR=1.33; 95% CI: 1.00, 1.77; P = 0.047), although additive effect estimates were similar. Each 0.10 unit change in the AD-GRS was associated with a -0.07 (95% CI: -0.09, -0.05; P < 0.001) SD difference in memory score among NHW aged 50+, but no significant differences among NHB (β = -0.01; 95% CI: -0.04, 0.01; P = 0.546). [Correction added on 29 July 2014, after first online publication: confidence intervalshave been amended.] The estimated effect of the GRS was significantly smaller among NHB than NHW (P < 0.05) for both outcomes.

CONCLUSION

This analysis provides evidence for differential relative effects of the GRS on dementia probability and memory score among NHW and NHB in a new, national data set.

Dementia and dependence: do modifiable risk factors delay disability?

OBJECTIVE

To identify modifying factors that preserve functional independence among individuals at high dementia risk.

METHODS

Health and Retirement Study participants aged 65 years or older without baseline activities of daily living (ADL) limitations (n = 4,922) were interviewed biennially for up to 12 years. Dementia probability, estimated from direct and proxy cognitive assessments, was categorized as low (i.e., normal cognitive function), mild, moderate, or high risk (i.e., very impaired) and used to predict incident ADL limitations (censoring after limitation onset). We assessed multiplicative and additive interactions of dementia category with modifiers (previously self-reported physical activity, smoking, alcohol consumption, depression, and income) in predicting incident limitations.

RESULTS

Smoking, not drinking, and income predicted incident ADL limitations and had larger absolute effects on ADL onset among individuals with high dementia probability than among cognitively normal individuals. Smoking increased the 2-year risk of ADL limitations onset from 9.9% to 14.9% among the lowest dementia probability category and from 32.6% to 42.7% among the highest dementia probability category. Not drinking increased the 2-year risk of ADL limitations onset by 2.1 percentage points among the lowest dementia probability category and 13.2 percentage points among the highest dementia probability category. Low income increased the 2-year risk of ADL limitations onset by 0.4% among the lowest dementia probability category and 12.9% among the highest dementia probability category.

CONCLUSIONS

Smoking, not drinking, and low income predict incident dependence even in the context of cognitive impairment. Regardless of cognitive status, reducing these risk factors may improve functional outcomes and delay institutionalization.