Stroke Severity, Caregiver Feedback, and Cognition in the REGARDS-CARES Study

Objective

Cognitive impairment after stroke is common, present up to 60% of survivors. Stroke severity, indicated by both volume and location, is the most consequential predictor of cognitive impairment, with severe strokes predicting higher chances of cognitive impairment. The current investigation examines the associations of two stroke severity ratings and a caregiver-report of post-stroke functioning with longitudinal cognitive outcomes.

Methods

The analysis was conducted on 157 caregivers and stroke survivor dyads who participated in the Caring for Adults Recovering from the Effects of Stroke (CARES) project, an ancillary study of the REasons for Geographic and Racial Differences in Stroke (REGARDS) national cohort study. Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) collected at hospitalization discharge were included as two primary predictors of cognitive impairment. The number of caregiver-reported problems and impairments at nine months following stroke were included as a third predictor. Cognition was assessed using a biennial telephone battery, incorporating multiple cognitive assessments to assess learning, memory, and executive functioning. Longitudinal cognitive scores were analyzed up to five years post-stroke, controlling for baseline (pre-stroke) cognitive scores and demographic variables of each stroke survivor collected at CARES baseline.

Results

Separate mixed models showed significant main effects of GOS (b=0.3280, p=0.0009), mRS (b=-0.2119, p=0.0002), and caregiver-reported impairments (b=-0.0671, p<0.0001) on longitudinal cognitive scores. In a combined model including all three predictors, only caregiver-reported problems significantly predicted cognitive outcomes (b=-0.0480, p<0.0001).

Impact

These findings underscore the importance of incorporating caregivers feedback in understanding cognitive consequences of stroke.

Racial differences in persistence to secondary prevention medication regimens after ischemic stroke

BACKGROUND

Prior stroke is one of the biggest risk factors for future stroke events. Effective secondary prevention medication regimens can dramatically reduce recurrent stroke risk. Guidelines recommend the use of antithrombotic, antihypertensive and lipid-lowering medications after stroke. Medication adherence is known to be better in the presence of a caregiver but long-term adherence after stroke is unknown and disparities may persist.

METHODS

We examined the effects of race and sex on baseline prescription and maintenance of secondary prevention regimens in the presence of a caregiver using the Caring for Adults Recovering from the Effects of Stroke (CARES) study, an ancillary study of the national REasons for Geographic and Racial Differences in Stroke (REGARDS).

RESULTS

Incident ischemic stroke survivors (N = 172; 36% Black) with family caregivers had medications recorded at hospital discharge and on average 9.8 months later during a home visit. At discharge, antithrombotic prescription (95.9%), lipid-lowering medications (78.8%) and antihypertensives (89.9%) were common and there were no race or sex differences in discharge prescription rates. One year later, medication persistence had fallen to 86.6% for antithrombotics (p = 0.002) and 69.8% for lipid lowering (p = 0.008) but increased to 93.0% for antihypertensives (p = 0.30). Blacks were more likely to have discontinued antithrombotics than Whites (18.3% v 7.7%, p = 0.04). No significant differences in persistence were seen with age, sex, income, depression, or cognitive impairment.

CONCLUSIONS

Medication persistence was high in this sample, likely due to the presence of a caregiver. In our cohort, despite similar prescription rates at the time of hospital discharge, Black stroke survivors were more than twice as likely to stop antithrombotics than Whites. The effect of changes in patterns of medication usage on health outcomes in Black stroke survivors warrants continued investigation.

Continuous cardiac rhythm monitoring post-stroke: A feasibility study in REGARDS

OBJECTIVES

Cardiac rhythm monitoring is increasingly used after stroke. We studied feasibility of telephone guided, mail-in ambulatory long-term cardiac rhythm monitoring in Black and White stroke survivors. MATERIALS AND METHODS;: We contacted 28 participants of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who had an ischemic stroke during follow-up. After obtaining informed consent by telephone, a noninvasive 14-day cardiac rhythm monitoring device (ZIO® XT patch; iRhythm Technologies, San Francisco, CA) was mailed to each participant. We evaluated the results of telephone consent, follow-up calls, compliance and wear time as the primary objective. Secondarily, we reported prevalence of atrial and ventricular arrhythmias.

RESULTS

The majority of those contacted (20/28 = 71%) agreed to enroll in the monitoring study. Non-participation was nominally more common in Black than White participants; 6/16 (37.5%) vs. 2/12 (17%). Of those who agreed, 15 participants (75%, 6 Black, 9 White) completed ambulatory monitoring with mean wear time 12.9 ± 2.5 days. Arrhythmias were observed in two-thirds of the 15 participants: AF in 2, brief atrial tachycardia in 12, NSVT in 2, premature ventricular contractions in 3, and pause or atrioventricular block in 2.

CONCLUSIONS

Non-invasive rhythm monitoring was feasible in this pilot from a large, national cohort study of stroke survivors that employed a telephone guided, mail-in monitoring system, and these preliminary results suggest a high prevalence of arrhythmias. Increased emphasis on recruitment strategies for Black stroke survivors may be required. We demonstrated a high yield of significant cardiac arrhythmias among post-stroke participants who completed monitoring.

Sleep Quality Reports From Family Caregivers and Matched Non-caregiving Controls in a Population-Based Study

The stress of family caregiving may affect many health-related variables, including sleep. We evaluated differences in self-reported sleep quality between incident caregivers and matched non-caregiving controls from a national population-based study. Caregivers and controls were identified in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study and matched on seven different demographic and health history factors. Caregivers reported significantly longer sleep onset latency than controls, before and after adjusting for covariates (ps < .05). No differences were found on measures of total sleep time or sleep efficiency. Among caregivers only, employed persons reported less total sleep time and number of care hours was a significant predictor of total sleep time. Dementia caregivers did not differ from other caregivers. This is one of the few population-based studies of sleep quality in family caregivers. Additional research is needed to examine whether sleep disturbance contributes to greater health problems among caregivers.

Family caregivers emphasise patience and personal growth: a qualitative analysis from the Caregiving Transitions Study

Background

informal caregiving for family and friends is becoming increasingly common due to the rising prevalence of chronic conditions and a shortage of affordable care options. While the impact of caregiving on caregivers’ health is well-documented, nuances in caregivers’ experiences may not be captured in quantitative studies. We aimed to better understand caregivers’ perception of their experiences through qualitative analysis.

Methods

participants were from the Caregiving Transitions Study (CTS), which is ancillary to the REasons for Geographic and Racial Differences in Stroke Study. We analysed responses from 150 caregivers to an open-ended question at the end of the CTS telephone interview concerning additional information about their caregiving experiences. We identified main themes and examined differences by sex, condition and relationship to the care recipient.

Results

four major themes were identified: cultural/family expectations; growth opportunities; and reciprocity; stressors and challenges and recommendations. Male caregivers more often indicated that their motivation for taking on this role was their sense of duty towards family, while female caregivers focused on the challenges and burden of caregiving that they experienced. Overall, caregivers highlighted the importance of patience and the positive impact of caregiving, such as opportunities for personal growth, acquiring new skills, and finding fulfillment and gratitude.

Conclusions

family caregivers shared both positive and challenging experiences as well as the impact that these experiences had on their lives. Understanding the full spectrum of the caregiving experience will help inform how the community and the health care system can best support caregivers in their roles.

Sleep Quality in Family Caregivers and Matched Non-Caregiving Controls: The REGARDS Study

The high levels of stress experienced by family caregivers may affect their physical and psychological health, including their sleep quality. However, there are few population-based studies comparing sleep between family caregivers and carefully-matched controls. We evaluated differences in sleep and identified predictors of poorer sleep among the caregivers, in a comparison of 251 incident caregivers and carefully matched non-caregiving controls, recruited from the national REasons for Geographic and Racial Differences in Stroke (REGARDS) Study. Incident caregivers and controls were matched on up to seven demographic and health factors (age, sex, race, education level, marital status, self-rated health, and self-reported serious cardiovascular disease history). Sleep characteristics were self-reported and included total sleep time, sleep onset latency, wake after sleep onset, time in bed, and sleep efficiency. Family caregivers reported significantly longer sleep onset latency, before and after adjusting for potential confounders, compared to non-caregiving controls (ps < 0.05). Depressive symptoms in caregivers predicted longer sleep onset latency, greater wake after sleep onset, and lower sleep efficiency. Longer total sleep time in caregivers was predicted by employment status, living with the care recipient, and number of caregiver hours. Employed caregivers and caregivers who did not live with the care recipient had shorter total sleep time and spent less time in bed than non-employed caregivers. Additional research is needed to evaluate whether sleep disturbances contributes to health problems among caregivers.

A qualitative analysis of family caregiver perspectives from the Caregiving Transitions Study

As people live longer, informal caregiving for family and friends is becoming increasingly common. Caregiver satisfaction with their role is now of greater importance to an increasing proportion of the U.S. population. Most research on caregivers has studied convenience samples, often restricted to caregivers of people with dementia. Various studies have examined the impact of caregiving on caregivers’ health but to our knowledge there are no qualitative studies of caregiving experiences from caregivers in population-based samples. This study investigated the impact of caregiving on participants who transitioned into a caregiving role while participating in a national population-based study. Participants were from the Caregiving Transitions Study, which is ancillary to the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study. We thematically analyzed responses from 150 caregivers providing care for multiple different conditions to an open-ended question asked at the time of enrollment and designed to encourage caregivers to share additional details about their caregiving experience. Four major themes were identified: cultural/family expectations; growth opportunities and reciprocity; stressors and challenges; and recommendations. Participants shared both positive and challenging experiences in their role as a family caregiver as well as the impact that these experiences had on their lives. Caregivers shared that one of the most important motivations for taking on this role was their sense of duty toward family. Caregivers also highlighted the positive impact of caregiving on their lives such as opportunities for personal growth, acquisition of new skills, and finding a sense of fulfillment and gratitude.

Stress, Burden, and Well-Being in Dementia and Nondementia Caregivers: Insights From the Caregiving Transitions Study

BACKGROUND AND OBJECTIVES

Few population-based studies have directly compared caregivers of persons with dementia to caregivers of persons with other disabilities (nondementia caregivers). We enrolled dementia and nondementia caregivers who were providing substantial and sustained care and compared these groups on measures of caregiver stressors, appraisals of burden, and well-being.

RESEARCH DESIGN AND METHODS

Caregivers (N = 251) who provided continuous care for at least 1 year and at least 5 h per week were recruited from the population-based REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Caregivers reported on dementia caregiving status, stressors, burden, and well-being.

RESULTS

Forty-seven percent (n = 117) reported caring for a person with dementia. Dementia caregivers reported more stressors, providing more care for self-care and behavioral problems than nondementia caregivers. Dementia caregivers also reported higher appraisals of stress and burden, and more depressive symptoms, but did not differ from nondementia caregivers on mental and physical health quality of life. In multivariable-adjusted models, adjustment for the total number of care recipient problems attenuated differences between dementia and nondementia caregivers on burden and depression measures.

DISCUSSION AND IMPLICATIONS

Dementia and nondementia caregivers showed relatively few differences in indicators of overall well-being in this population-based sample, perhaps because both groups of caregivers in this study were providing substantial care. Dementia caregivers may require special assistance with dementia-specific problems such as behavioral problems. Clinical interventions and policy changes targeting highly burdened caregivers are needed to support them in allowing their care recipients to age in place at home.

Physical Activity Patterns After Retirement: The REGARDS Study

Major life events, such as retirement, may lead to dramatic shifts in physical activity (PA) patterns. However, there are limited empirical data quantifying the magnitude of these changes. Our aims were to objectively measure PA before and after retirement and to describe changes in participation in various types of PA. Participants were employed black and white men and women enrolled in REGARDS (REasons for Geographic and Racial Differences in Stroke), a national prospective cohort study (n=581, mean age 64 years, 25% black, 51% women). Participants met inclusion criteria if they retired between their first and second accelerometer wearing (2009-2013 and 2017-2018, respectively) and had valid accelerometer data (>4 days with >10 hours/day pre- and post-retirement). Accelerometer-based PA was categorized into average minutes per day spent in sedentary, light-intensity, and moderate-to-vigorous PA. Participants reported changes (less, same, more) in 12 types of PA. After retirement, participants decreased both sedentary time (by 36.3 minutes/day) and moderate-to-vigorous PA (by 5.6 minutes/day). Conversely, there was an increase in light-intensity PA (+18.1 minutes/day) after retirement. Participants reported changes in their participation level in various PA activities. For example, 41% reported an increased amount of TV viewing, 42% reported less walking, and 31% reported increased participation in volunteer activities. Findings indicate that retirement coincides with a change in the time spent in each intensity category and the time spent across a range of activity types. Further research is warranted to examine how these changes in physical activity patterns influence post-retirement health status.

REGARDS Cognitive Assessment and Approaches to Defining Cognitive Impairment and Change in Cognitive Function

Since 2003, REGARDS participants have taken part in telephone-based cognitive assessments. Global cognitive status is assessed annually with the Six-item Screener. Between 2006 and 2009, measures of learning and memory (CERAD Word List) and language/executive function (Animal and Letter Fluency) were implemented, and are administered biennially. A Brain Health Substudy, conducting in-home clinical examinations of neuropsychological, neurological, and functional status among 1000 participants, is underway to validate telephone assessments and estimate prevalence of VCID in REGARDS. Approaches to defining incident cognitive impairment and cognitive change, including definitions employed for case/cohort studies using stored blood samples, will be described. We will discuss psychometric and methodological considerations for characterization of risks for cognitive impairment across race and region, as well as longitudinal trajectories of cognitive function.

Enrolling Incident Caregivers and Matched Controls From a Nationwide Epidemiological Study

Participants in the national Reasons for Geographic and Racial Differences in Stroke (REGARDS) study were asked about family caregiving responsibilities at enrollment (2003-2007). Among the 88% of participants who were not caregivers at enrollment, 1,229 reported becoming caregivers before a follow-up interview 12 years later. The Caregiving Transitions Study screened these participants and enrolled 251 as incident caregivers. All reported 5 or more hours of care per week, provided assistance with at least one ADL or IADL, and were caregivers for at least 3 months before a 2nd blood sample was obtained in the REGARDS study. A total of 251 noncaregiving control participants who reported no caregiving responsibilities over this 12-year period were also enrolled. Each control was matched to a caregiver on age (+ 5 years), sex, race, other demographics, and baseline (pre-caregiving) health variables. Descriptive analyses confirm the unique comparability of the samples compared to previous caregiving studies.

Association Between Patients' Self-Reported Gaps in Care Coordination and Preventable Adverse Outcomes: a Cross-Sectional Survey

BACKGROUND

Whether patients' reports of gaps in care coordination reflect clinically significant problems is unclear.

OBJECTIVE

To determine any association between patient-reported gaps in care coordination and patient-reported preventable adverse outcomes.

DESIGN AND PARTICIPANTS

We administered a cross-sectional survey on experiences with healthcare to participants in the national Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who were ≥ 65 years old. Of the 15,817 participants in REGARDS at the time of our survey (August 2017-November 2018), 11,138 completed the survey. We restricted the sample to participants who reported ≥ 2 ambulatory visits and ≥ 2 ambulatory providers in the past year (N = 7568).

MAIN MEASURES

We considered 7 gaps in ambulatory care coordination, elicited with previously validated questions. We considered 4 outcomes: (1) a test that was repeated because the doctor did not have the result of the first test, (2) a drug-drug interaction that occurred due to multiple prescribers, (3) an emergency department visit that could have been prevented by better communication among providers, and (4) a hospital admission that could have been prevented by better communication among providers. We used logistic regression to determine the association between ≥ 1 gap in care coordination and ≥ 1 preventable outcome, adjusting for potential confounders.

KEY RESULTS

The average age of the sample was 77.0 years; 55% were female, and 34% were African-American. More than one-third of participants (38.1%) reported ≥ 1 gap in care coordination and nearly one-tenth (9.8%) reported ≥ 1 preventable outcome. Having ≥ 1 gap in care coordination was associated with an increased odds of ≥ 1 preventable outcome (adjusted odds ratio 1.55; 95% confidence interval 1.33, 1.81).

CONCLUSIONS

Participants' reports of gaps in care coordination were associated with an increased odds of preventable adverse outcomes. Future interventions should leverage patients' observations to detect and resolve gaps in care coordination.

Effects of Transitions to Family Caregiving on Well-Being: A Longitudinal Population-Based Study

BACKGROUND/OBJECTIVES

Few studies have rigorously examined the magnitude of changes in well-being after a transition into sustained and substantial caregiving, especially in population-based studies, compared with matched noncaregiving controls.

DESIGN

We identified individuals from a national epidemiological investigation who transitioned into caregiving over a 10- to 13-year follow-up and provided continuous in-home care for at least 18 months and at least 5 hours per week. Individuals who did not become caregivers were individually matched with caregivers on age, sex, race, education, marital status, self-rated health, and history of cardiovascular disease at baseline. Both groups were assessed at baseline and follow-up.

SETTING

REasons for Geographic And Racial Differences in Stroke study.

PARTICIPANTS

A total of 251 incident caregivers and 251 matched controls.

MEASUREMENTS

Perceived Stress Scale (PSS), 10-Item Center for Epidemiological Studies-Depression (CES-D), and 12-item Short-Form Health Survey quality-of-life mental (MCS) and physical (PCS) component scores.

RESULTS

Caregivers showed significantly greater worsening in PSS, CES-D, and MCS, with standardized effect sizes ranging from 0.676 to 0.796 compared with changes in noncaregivers. A significant but smaller effect size was found for worsening PCS in caregivers (0.242). Taking on sustained caregiving was associated with almost a tripling of increased risk of transitioning to clinically significant depressive symptoms at follow-up. Effects were not moderated by race, sex, or relationship to care recipient, but younger caregivers showed greater increases in CES-D than older caregivers.

CONCLUSION

Persons who began substantial, sustained family caregiving had marked worsening of psychological well-being, and relatively smaller worsening of self-reported physical health, compared with carefully matched noncaregivers. Previous estimates of effect sizes on caregiver well-being have had serious limitations due to use of convenience sampling and cross-sectional comparisons. Researchers, public policy makers, and clinicians should note these strong effects, and caregiver assessment and service provision for psychological well-being deserve increased priority.

Evaluation of Racial Disparities in Hospice Use and End-of-Life Treatment Intensity in the REGARDS Cohort

IMPORTANCE

Although hospice use is increasing and patients in the US are increasingly dying at home, racial disparities in treatment intensity at the end of life, including hospice use, remain.

OBJECTIVE

To examine differences between Black and White patients in end-of-life care in a population sample with well-characterized causes of death.

DESIGN, SETTING, AND PARTICIPANTS

This study used data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, an ongoing population-based cohort study with enrollment between January 25, 2003, and October 3, 2007, with linkage to Medicare claims data. Multivariable logistic regression models were used to examine racial and regional differences in end-of-life outcomes and in stroke mortality among 1212 participants with fee-for-service Medicare who died between January 1, 2013, and December 31, 2015, owing to natural causes and excluding sudden death, with oversampling of Black individuals and residents of Southeastern states in the United States. Initial analyses were conducted in March 2019, and final primary analyses were conducted in February 2020.

MAIN OUTCOMES AND MEASURES

The primary outcomes of interest were hospice use of 3 or more days in the last 6 months of life derived from Medicare claims files. Other outcomes included multiple hospitalizations, emergency department visits, and use of intensive procedures in the last 6 months of life. Cause of death was adjudicated by an expert panel of clinicians using death certificates, proxy interviews, autopsy reports, and medical records.

RESULTS

The sample consisted of 1212 participants (630 men [52.0%]; 378 Black individuals [31.2%]; mean [SD] age at death, 81.0 [8.6] years) of 2542 total deaths. Black decedents were less likely than White decedents to use hospice for 3 or more days (132 of 378 [34.9%] vs 385 of 834 [46.2%]; P < .001). After stratification by cause of death, substantial racial differences in treatment intensity and service use were found among persons who died of cardiovascular disease but not among patients who died of cancer. In analyses adjusted for cause of death (dementia, cancer, cardiovascular disease, and other) and clinical and demographic variables, Black decedents were significantly less likely to use 3 or more days of hospice (odds ratio [OR], 0.72; 95% CI, 0.54-0.96) and were more likely to have multiple emergency department visits (OR, 1.35; 95% CI, 1.01-1.80) and hospitalizations (OR, 1.39; 95% CI, 1.02-1.89) and undergo intensive treatment (OR, 1.94; 95% CI, 1.40-2.70) in the last 6 months of life compared with White decedents.

CONCLUSIONS AND RELEVANCE

Despite the increase in the use of hospice care in recent decades, racial disparities in the use of hospice remain, especially for noncancer deaths. More research is required to better understand racial disparities in access to and quality of end-of-life care.

Depressive Symptoms After Ischemic Stroke: Population-Based Comparisons of Patients and Caregivers With Matched Controls

Background and Purpose- Persistent depression after ischemic stroke is common in stroke survivors and may be even higher in family caregivers, but few studies have examined depressive symptom levels and their predictors in patient and caregiver groups simultaneously. Methods- Stroke survivors and their family caregivers (205 dyads) were enrolled from the national REGARDS study (Reasons for Geographic and Racial Differences in Stroke) into the CARES study (Caring for Adults Recovering from the Effects of Stroke) ≈9 months after a first-time ischemic stroke. Demographically matched stroke-free dyads (N=205) were also enrolled. Participants were interviewed by telephone, and depressive symptoms were assessed with the 20-item Center for Epidemiological Studies-Depression scale. Results- Significant elevations in depressive symptoms (Ps<0.03) were observed for stroke survivors (M=8.38) and for their family caregivers (M=6.42) relative to their matched controls (Ms=5.18 and 4.62, respectively). Stroke survivors reported more symptoms of depression than their caregivers (P=0.008). No race or sex differences were found, but differential prediction of depressive symptom levels was found across patients and caregivers. Younger age and having an older caregiver were associated with more depressive symptoms in stroke survivors while being a spouse caregiver and reporting fewer positive aspects of caregiving were associated with more depressive symptoms in caregivers. The percentage of caregivers at risk for clinically significant depression was lower in this population-based sample (12%) than in previous studies of caregivers from convenience or clinical samples. Conclusions- High depressive symptom levels are common 9 months after first-time ischemic strokes for stroke survivors and family caregivers, but rates of depressive symptoms at risk for clinical depression were lower for caregivers than previously reported. Predictors of depression differ for patients and caregivers, and standards of care should incorporate family caregiving factors.

Sex and Race Differences in the Association of Incident Ischemic Stroke With Risk Factors

Importance

Race-specific and sex-specific stroke risk varies across the lifespan, yet few reports describe sex differences in stroke risk separately in black individuals and white individuals.

Objective

To examine incidence and risk factors for ischemic stroke by sex for black and white individuals.

Design, Setting, and Participants

This prospective cohort study included participants 45 years and older who were stroke-free from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort, enrolled from the continental United States 2003 through 2007 with follow-up through October 2016. Data were analyzed from March 2018 to September 2018.

Exposures

Sex and race.

Main Outcomes and Measures

Physician-adjudicated incident ischemic stroke, self-reported race/ethnicity, and measured and self-reported risk factors.

Results

A total of 25 789 participants (14 170 women [54.9%]; 10 301 black individuals [39.9%]) were included. Over 222 120 person-years of follow-up, 939 ischemic strokes occurred: 159 (16.9%) in black men, 326 in white men (34.7%), 217 in black women (23.1%), and 237 in white women (25.2%). Between 45 and 64 years of age, white women had 32% lower stroke risk than white men (incidence rate ratio [IRR], 0.68 [95% CI, 0.49-0.94]), and black women had a 28% lower risk than black men (IRR, 0.72 [95% CI, 0.52-0.99]). Lower stroke risk in women than men persisted at age 65 through 74 years in white individuals (IRR, 0.71 [95% CI, 0.55-0.94]) but not in black individuals (IRR, 0.94 [95% CI, 0.68-1.30]); however, the race-sex interaction was not significant. At 75 years and older, there was no sex difference in stroke risk for either race. For white individuals, associations of systolic blood pressure (women: hazard ratio [HR], 1.13 [95% CI, 1.05-1.22]; men: 1.04 [95% CI, 0.97-1.11]; P = .099), diabetes (women: HR, 1.84 [95% CI, 1.35-2.52]; men: 1.13 [95% CI, 0.86-1.49]; P = .02), and heart disease (women: HR, 1.76 [95% CI, 1.30-2.39]; men, 1.26 [95% CI, 0.99-1.60]; P = .09) with stroke risk were larger for women than men, while antihypertensive medication use had a smaller association in women than men (women: HR, 1.17 [95% CI, 0.89-1.54]; men: 1.61 [95% CI, 1.29-2.03]; P = .08). In black individuals, there was no evidence of a sex difference for any risk factors.

Conclusions and Relevance

For both races, at age 45 through 64 years, women were at lower stroke risk than men, and there was no sex difference at 75 years or older; however, the sex difference pattern may differ by race from age 65 through 74 years. The association of risk factors on stroke risk differed by race-sex groups. While the need for primordial prevention, optimal management, and control of risk factors is universal across all age, racial/ethnic, and sex groups, some demographic subgroups may require earlier and more aggressive strategies.

DEMENTIA CAREGIVING NEGATIVELY AFFECTS THE HEALTH OF CAREGIVER AND CARE RECIPIENT. CAREGIVING TRANSITIONS STUDY

Dementia is one of the most common reasons for needing a caregiver (CG). Few studies have compared dementia and non-dementia caregivers who have transitioned into family caregiving roles. Participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study who transitioned into a significant caregiving role were recruited to participate in the Caregiving Transitions Study (CTS). Of 11,483 REGARDS participants who were not caregivers at baseline, 1229 (11%) transitioned into a family caregiving role. Eligibility criteria were met by 251 and they were enrolled along with 251 demographically-matched noncaregiving controls. Enrolled caregivers are 65% female; 36% African American; 71.8 + 8.1 years of age; caring for a spouse/partner (51%), parent (25%), or another person (24%). 47% are caring for a person with dementia. Dementia CGs provide more hours of care per day (9.3 hours versus 6.7 hours), report being under more stress and twice as much strain as non-dementia CGs (p<0.03 for all). They feel more burdened by the care recipient’s treatment (p=0.01) and report that the burden leads to delays in the care recipient receiving medical care (p<0.007). Dementia CGs are more than twice as likely as non-caregivers to report that their caregiving makes them worse at taking care of their own health (33.9% versus 15.4%, p=0.003). This prospective, population-based study confirms previous cross-sectional findings from convenience samples on the greater care burden experienced by dementia caregivers and extends this work to new measures of treatment burden and treatment delay.

RACIAL DISPARITIES IN HOSPICE USE AT THE END OF LIFE: FINDINGS FROM THE REGARDS STUDY

Hospice supports patients and families through interdisciplinary care focused on symptom management and maximization of quality of life. Although hospice care confers well-documented benefits, it remains underutilized: many patients do not use it at all or enter care too late to receive any benefit. While racial disparities in hospice use have been documented, hospice utilization among non-white decedents remains understudied, particularly among those with non-cancer diagnoses. Therefore, we used the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a population-based investigation of stroke incidence with oversampling of Blacks and cause of death adjudication by expert panel review, linked to Medicare claims data to examine racial disparities in end-of-life care. We identified 1221 participants who died between 2013-2015 due to natural causes excluding sudden death. More than half (52.8%) used hospice during the last 6 months of life (median =15 days), with use among cancer decedents over 70%. Overall, Blacks were significantly less likely to use hospice (OR=0.570) compared to Whites in adjusted analyses. Among hospice users, Blacks did not significantly differ from Whites in length of stay. In analyses stratified by cause of death (dementia, cancer, CVD and other), Blacks were significantly less likely than Whites to use hospice for all causes of death other than dementia. Despite tremendous growth of hospice in recent decades, our findings suggest that this effective service remains highly underutilized among Blacks dying from cancer, CVD and other serious illnesses, suggesting a need for targeted intervention to eliminate disparities in quality end-of-life care.

Participation in Get With The Guidelines-Stroke and Its Association With Quality of Care for Stroke

Importance

Get With The Guidelines-Stroke (GWTG-Stroke) is an American Heart Association/American Stroke Association stroke-care quality-improvement program; however, to our knowledge, there has not been a direct comparison of the quality of care between patients hospitalized at participating hospitals and those at nonparticipating hospitals.

Objective

To contrast quality of stroke care measures for patients admitted to hospitals participating and not participating in GWTG-Stroke.

Design, Setting, and Participants

Subpopulation of 546 participants with ischemic stroke occurring during a 9-year follow-up of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a population-based cohort study of 30 239 randomly selected black and white participants 45 years and older recruited between 2003 and 2007. Of those with stroke, 207 (36%) were treated in a hospital participating in GWTG-Stroke and 339 in a nonparticipating hospital. Data were analyzed between July 29, 2017, and April 17, 2018.

Main Outcomes and Measures

Quality of care measures including use of tissue plasminogen activator, performance of swallowing evaluation, antithrombotic use in first 48 hours, lipid profile assessment, discharge receiving antithrombotic therapy, discharge receiving a statin, neurologist evaluation, providing weight loss and exercise counseling, education on stroke risk factors and warning signs, and assessment for rehabilitation.

Results

Participants treated at participating hospitals had a mean (SD) age of 74 (8) years and 100 of 207 were men (48%), while those seen at nonparticipating hospitals had a mean (SD) age of 73 (9) years, and 161 of 339 were men (48%). Those seen in participating hospitals were more likely to receive 5 of 10 evidence-based interventions recommended for patients hospitalized with ischemic stroke, including receiving tissue plasminogen activator (RR, 3.74; 95% CI, 1.65-8.50), education on risk factors (RR, 1.54; 95% CI, 1.16-2.05), having an evaluation for swallowing (RR, 1.25; 95% CI, 1.04-1.50), a lipid evaluation (RR, 1.18; 95% CI, 1.05-1.32), and an evaluation by a neurologist (RR, 1.12; 95% CI, 1.05-1.20). Those seen in participating hospitals received a mean of 5.4 (95% CI, 5.2-5.6) interventions compared with 4.8 (95% CI, 4.6-5.0) in nonparticipating hospitals (P < .001).

Conclusions and Relevance

These data collected independently of the GWTG-Stroke program document improved stroke care for patients with ischemic stroke hospitalized at participating hospitals.

Does the Association of Diabetes With Stroke Risk Differ by Age, Race, and Sex? Results From the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

OBJECTIVE

Given temporal changes in diabetes prevalence and stroke incidence, this study investigated age, race, and sex differences in the diabetes-stroke association in a contemporary prospective cohort, the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

RESEARCH DESIGN AND METHODS

We included 23,002 non-Hispanic black and white U.S. adults aged ≥45 years without prevalent stroke at baseline (2003-2007). Diabetes was defined as fasting glucose ≥126 mg/dL, random glucose ≥200 mg/dL, or use of glucose-lowering medication. Incident stroke events were expert adjudicated and available through September 2017.

RESULTS

The prevalence of diabetes was 19.1% at baseline. During follow-up, 1,018 stroke events occurred. Among adults aged <65 years, comparing those with diabetes to those without diabetes, the risk of stroke was increased for white women (hazard ratio [HR] 3.72 [95% CI 2.10-6.57]), black women (HR 1.88 [95% CI 1.22-2.90]), and white men (HR 2.01 [95% CI 1.27-3.27]) but not black men (HR 1.27 [95% CI 0.77-2.10]) after multivariable adjustment. Among those aged ≥65 years, diabetes increased the risk of stroke for white women and black men, but not black women (HR 1.05 [95% CI 0.74-1.48]) or white men (HR 0.86 [95% CI 0.62-1.21]).

CONCLUSIONS

In this contemporary cohort, the diabetes-stroke association varied by age, race, and sex together, with a more pronounced effect observed among adults aged <65 years. With the recent increase in the burden of diabetes complications at younger ages in the U.S., additional efforts are needed earlier in life for stroke prevention among adults with diabetes.

Differences in Risk of Sudden Cardiac Death Between Blacks and Whites

BACKGROUND

Prior studies have consistently demonstrated that blacks have an approximate 2-fold higher incidence of sudden cardiac death (SCD) than whites; however, these analyses have lacked individual-level sociodemographic, medical comorbidity, and behavioral health data.

OBJECTIVES

The purpose of this study was to evaluate whether racial differences in SCD incidence are attributable to differences in the prevalence of risk factors or rather to underlying susceptibility to fatal arrhythmias.

METHODS

The Reasons for Geographic and Racial Differences in Stroke study is a prospective, population-based cohort of adults from across the United States. Associations between race and SCD defined per National Heart, Lung, and Blood Institute criteria were assessed.

RESULTS

Among 22,507 participants (9,416 blacks and 13,091 whites) without a history of clinical cardiovascular disease, there were 174 SCD events (67 whites and 107 blacks) over a median follow-up of 6.1 years (interquartile range: 4.6 to 7.3 years). The age-adjusted SCD incidence rate (per 1,000 person-years) was higher in blacks (1.8; 95% confidence interval [CI]: 1.4 to 2.2) compared with whites (0.7; 95% CI: 0.6 to 0.9), with an unadjusted hazard ratio of 2.35; 95% CI: 1.74 to 3.20. The association of black race with SCD risk remained significant after adjustment for sociodemographics, comorbidities, behavioral measures of health, intervening cardiovascular events, and competing risks of non-SCD mortality (hazard ratio: 1.97; 95% CI: 1.39 to 2.77).

CONCLUSIONS

In a large biracial population of adults without a history of cardiovascular disease, SCD rates were significantly higher in blacks as compared with whites. These racial differences were not fully explained by demographics, adverse socioeconomic measures, cardiovascular risk factors, and behavioral measures of health.

Abstract WP213: Age-specific Black-white Differences in 30-day Post-Stroke Fatality in the National Regards Study

Introduction: Previous studies have suggested that post-stroke case fatality in blacks is similar to or lower than that in whites. Black-white (B-W) differences in case fatality have not been examined within age strata.

Methods: This study was conducted in REGARDS, a national population-based cohort enrolled in 2003-2007, followed for stroke events through September 30, 2017 and deaths through March 31, 2018. Medical records of suspected stroke events were retrieved and adjudicated by physicians. Case fatality (defined as death within 30-days of stroke event) following ischemic stroke was examined within age strata (45-64, 65-74 and 75+) among REGARDS participants aged 45+ who were stroke-free at baseline. Logistic regression was used to examine B-W differences in case-fatality after adjustment for sex, additional adjustment for the “Framingham risk factors,” and additional adjustment for socio-economic status (income and education).

Results: There were 1,104 physician-adjudicated incident ischemic stroke events among 28,253 participants over a median of 9.4 years of follow-up. Case fatality was 9.8% (63/643) in whites and 6.1% (28/461) in blacks (B-W Odds Ratio (OR) = 0.60; 95% CI: 0.39 - 0.95). Case fatality significantly increased across age strata in whites (p trend ≤ 0.0001) but not blacks (p trend = 0.85) (see table.) At ages 45-64, the sex-adjusted B-W case fatality OR was 1.33 (95% CI: 0.56 - 3.11), and decreased to 0.42 (95% CI: 0.19 - 0.93) for ages 75+ (p trend = 0.013). Adjustment for risk factors and SES did not mediate the trend for lower case fatality in blacks at older ages (p trend = 0.012).

Conclusions: These data confirm the lower stroke case-fatality in blacks compared to whites across the age-span of our study, and suggest that the benefit among black stroke patients is greatest at older ages.

Use of Medicare Claims Data for the Identification of Myocardial Infarction: The Reasons for Geographic And Racial Differences in Stroke Study

OBJECTIVES

Assess the validity of Medicare claims for identifying myocardial infarction (MI).

METHODS

We used data from 9951 Medicare beneficiaries 65 years and above in the Reasons for Geographic And Racial Differences in Stroke study. Between 2003 and 2012, 669 participants had an MI identified and adjudicated through study procedures (ie, the gold standard), and 552 had an overnight inpatient claim with a code for MI (ICD-9 code 410.x0 or 410.x1) in any discharge diagnosis position.

RESULTS

Using Medicare claims with a discharge diagnosis code for MI in any position, the positive predictive value (PPV) was 84.3% [95% confidence interval (CI), 80.9%-87.3%] and the sensitivity was 49.0% (95% CI, 44.9%-53.1%). Sensitivity was lower for men (45.8%) versus women (55.1%), microsize MIs (13.7%) versus other MIs (64.7%), type 2 (30.9%), and 4-5 MIs (11.1%) versus type 1 MIs (76.6%), and MIs occurring in-hospital (28.8%) versus out-of-hospital (66.7%). Using Medicare claims with a code for MI in the primary discharge diagnosis position, the PPV was 89.7% (95% CI, 86.3%-92.5%) and sensitivity was 40.1% (95% CI, 36.1%-44.2%). The sensitivity of claims with a code for MI in the primary discharge diagnosis position was lower for microsize versus other MIs, type 2 and 4-5 MIs versus type 1 MIs and MIs occurring in-hospital versus out-of-hospital. Hazard ratios for MI associated with participant characteristics were similar using adjudicated MIs identified through study procedures or claims for MI without further adjudication.

CONCLUSIONS

Medicare claims have a high PPV but low sensitivity for identifying MI and can be used to investigate individual-level characteristics associated with MI.

Is self or caregiver report comparable to Medicare claims indicators of healthcare utilization after stroke?

Background Claims data from Medicare or other payers might not generalize to other populations regarding service use after stroke especially among younger patients. However, high agreement between self-report and Medicare claims data would support the use of self-reported healthcare utilization data in these populations. Methods A population-based sample of 147 stroke participants with traditional fee-for service Medicare and their family caregivers was examined. Concordance with Medicare claims was examined for stroke participant self-report for Emergency Room visits, hospitalizations, and physician visits for a six-month period after stroke, and for both stroke participant and caregiver reports of receipt of Physical Therapy (PT), Speech and Language Pathology (SLP), or Home Health Agency (HHA) visits. Results Agreement was good for Emergency Room visits (kappa 0.75), hospitalization (kappa 0.70), and physician visits (Prevalence Adjusted Bias Adjusted Kappa [PABAK] 0.69) but more moderate for physical therapy, speech and language therapy, and home health agency visits (kappa 0.56-0.63). Caregiver agreement with Medicare claims was similar to stroke participant agreement. African Americans were less likely to self-report therapy compared to whites (OR 0.32 PT, 0.38 SLP, 0.29 HHA, p < 0.03). Younger stroke participants reported lower levels of Emergency Room visits than claims (OR 0.81, p = 0.001). Conclusion Healthcare utilization after stroke can be reliably assessed from Medicare claims, Stroke participant, or Caregiver report for salient events such as hospitalizations and Emergency Room visits. Self-report and caregiver report appear to be less reliable for identifying use of therapy or home health services. Caution should be used when interpreting disparities based on self-report data alone in these areas.

Reduced mortality rates among caregivers: Does family caregiving provide a stress-buffering effect?

Multiple studies have confirmed a seemingly paradoxical finding that family caregivers have lower mortality rates than comparable samples of noncaregivers. Caregivers are often also found to report more symptoms of depression and higher stress levels, but psychological distress and mortality are rarely examined in the same study. This study tests a possible mechanism for the mortality effect by applying a theoretical model that posits psychological and physiological stress-buffering benefits from prosocial helping behaviors. Participants in the population-based REasons for Geographic and Racial Differences in Stroke (REGARDS) study included 3,580 family caregivers who were individually matched to 3,580 noncaregivers on 15 demographic, health history, and health behavior variables using a propensity score matching algorithm. Baseline measures of depressive symptoms and perceived stress levels were also collected. The results indicated that caregivers reported significantly more depressive symptoms and higher perceived stress levels than propensity-matched noncaregivers (ps < .0001). However, consistent with our previous analysis (Roth et al., 2013), an analysis of 7-year survival rates showed that caregivers had a 16.5% lower mortality rate than noncaregivers (hazard ratio = 0.835, 95% CI = 0.719, 0.970). Significant caregiving*psychological distress interaction effects supported the stress-buffering hypothesis. Both depressive symptoms and perceived stress scores were significant predictors of mortality for the matched noncaregivers (ps < .0001), but not for the caregivers (ps > .49). Family caregiving appears to be similar to other prosocial helping behaviors in that it provides stress-buffering adaptations that ameliorate the impact of stress on major health outcomes such as mortality. (PsycINFO Database Record

Abstract 5: Differences in Stroke Care Among Patients in the REGARDS Study by Admission to a Hospital Participating versus Not Participating in GWTG-Stroke

Introduction: Get With The Guidelines (GWTG)-Stroke is a stroke-care quality-improvement program implemented in 1,656 of 5,564 (30%) US hospitals; however, the assessment of the effectiveness of GWTG is limited by the lack of data from hospitals not participating in the program.

Methods: The REasons for Geographic And Racial Differences in Stroke (REGARDS) is a national population-based longitudinal cohort study of 30,239 black & white participants aged 45+ years. Participants with an incident stroke were hospitalized in their local hospital. The proportion of patients receiving each of 10 quality-care metrics was calculated among the stroke victims admitted to hospitals with and without GWTG-Stroke. Logistic regression was used to adjust for participant and hospital differences of those seen in GWTG/non-GWTG hospitals.

Results: Between 2003 and 2015, 207 of the 546 (38%) REGARDS participants suffering an ischemic stroke were treated in a hospital currently participating in the GWTG-Stroke program (the remainder in a non-GWTG hospital). Those hospitalized in a GWTG hospital were of similar age, race, sex, and risk factor profile as those in non-GWTG hospital (data not shown); however, fewer residents of the Stroke Belt were treated in a GWTG hospital (46.9% vs. 60.8%). Among the hospitals where participants were treated, the GWTG hospitals significantly larger (average 425 versus 289 beds) and were more likely to participate in GME resident training (59.9% versus 40.7%). After adjustment for these differences (see table), patients treated in GWTG hospitals were more likely to receive tPA (OR = 3.69), education on stroke risk factors and warning signs (OR = 1.52), swallowing evaluation (OR = 1.26), lipid profile evaluation (OR = 1.17), and evaluation by a neurologist (OR = 1.12).

Conclusions: The care of stroke patients admitted to hospitals participating in the GWTG-Stroke were more likely to meet important stroke quality care metrics.

Medical therapy following hospitalization for heart failure with reduced ejection fraction and association with discharge to long-term care: a cross-sectional analysis of the REasons for Geographic And Racial Differences in Stroke (REGARDS) population

BACKGROUND

Less intensive treatment for heart failure with reduced ejection fraction (HFrEF) may be appropriate for patients in long-term care settings because of limited life expectancy, frailty, comorbidities, and emphasis on quality of life.

METHODS

We compared treatment patterns between REasons for Geographic And Racial Differences in Stroke (REGARDS) study participants discharged to long-term care versus home following HFrEF hospitalizations. We examined medical records and Medicare pharmacy claims for 147 HFrEF hospitalizations among 80 participants to obtain information about discharge disposition and medication prescriptions and fills.

RESULTS

Discharge to long-term care followed 22 of 147 HFrEF hospitalizations (15%). Participants discharged to long-term care were more likely to be prescribed beta-blockers and less likely to be prescribed aldosterone receptor antagonists and hydralazine/isosorbide dinitrate (96%, 14%, and 5%, respectively) compared to participants discharged home (81%, 22%, and 23%, respectively). The percentages of participants discharged to long-term care and home who had claims for filled prescriptions were similar for beta-blockers (68% versus 66%) and angiotensin converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARBs) (45% versus 47%) after 1 year. Smaller percentages of participants discharged to long-term care had claims for filled prescriptions of other medications compared to participants discharged home (diuretics: long-term care-50%, home-72%; hydralazine/isosorbide dinitrate: long-term care-5%, home-23%; aldosterone receptor antagonists: long-term care-5%, home-23%).

CONCLUSIONS

Differences in medication prescriptions and fills among individuals with HFrEF discharged to long-term care versus home may reflect prioritization of some medical therapies over others for patients in long-term care.

Age and Sex Disparities in Discharge Statin Prescribing in the Stroke Belt: Evidence From the Reasons for Geographic and Racial Differences in Stroke Study

BACKGROUND

Stroke is a costly and debilitating disease that disproportionately affects blacks. Despite the efficacy of statins, evidence suggests racial disparities may exist in statin prescribing.

METHODS AND RESULTS

We analyzed discharge medications for participants hospitalized for an ischemic stroke during follow-up of the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study. Medications on admission and discharge were abstracted from medical records. Among the 666 eligible incident strokes (2003-2013), analyses were restricted to 323 participants who were not statin users at the time of admission and had no history of atrial fibrillation. Overall, 48.7% were prescribed a statin on discharge. In the Stroke Belt, participants aged 65 years and older were 47% less likely to be discharged on a statin compared with those younger than 65 years (relative risk [RR], 0.53; 95% CI, 0.38-0.74). This association was not observed in non-Stroke Belt residents. Outside the Stroke Belt, blacks were more likely than whites to be discharged on a statin (RR, 1.42; 95% CI, 1.04-1.94), while no black:white association was present among Stroke Belt residents (RR, 0.93; 95% CI, 0.69-1.26; P for interaction=0.228). Compared with women, men in the Stroke Belt were 31% less likely to be discharged on a statin (RR, 0.69; 95% CI, 0.50-0.94) while men outside the Stroke Belt were more likely to be discharged on a statin (RR, 1.38; 95% CI, 0.99-1.92; P for interaction=0.004).

CONCLUSIONS

Statin discharge prescribing may differ among Stroke Belt and non-Stroke Belt residents, particularly in older Americans and men.

Comparison of Expert Adjudicated Coronary Heart Disease and Cardiovascular Disease Mortality With the National Death Index: Results From the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study

BACKGROUND

The National Death Index (NDI) is widely used to detect coronary heart disease (CHD) and cardiovascular disease (CVD) deaths, but its reliability has not been examined recently.

METHODS AND RESULTS

We compared CHD and CVD deaths detected by NDI with expert adjudication of 4010 deaths that occurred between 2003 and 2013 among participants in the REGARDS (REasons for Geographic And Racial Differences in Stroke) cohort of black and white adults in the United States. NDI derived CHD mortality had sensitivity 53.6%, specificity 90.3%, positive predictive value 54.2%, and negative predictive value 90.1%. NDI-derived CVD mortality had sensitivity 73.4%, specificity 84.5%, positive predictive value 70.6%, and negative predictive value 86.2%. Among NDI-derived CHD and CVD deaths, older age (odds ratios, 1.06 and 1.04 per 1-year increase) was associated with a higher probability of disagreement with the adjudicated cause of death, whereas among REGARDS adjudicated CHD and CVD deaths a history of CHD or CVD was associated with a lower probability of disagreement with the NDI-derived causes of death (odds ratios, 0.59 and 0.67, respectively).

CONCLUSIONS

The modest accuracy and differential performance of NDI-derived cause of death may impact CHD and CVD mortality statistics.

Obtaining Accelerometer Data in a National Cohort of Black and White Adults

PURPOSE

The objective of this study is to report methodological details and feasibility of conducting an accelerometer ancillary study in a large US cohort being followed for stroke and cognitive decline.

METHODS

Reasons for Geographic and Racial Differences in Stroke is a national population-based study of 30,239 blacks and whites, age ≥45 yr, enrolled January 2003 to October 2007. Baseline evaluations were conducted through computer-assisted telephone interview and an in-home visit. Participants are followed by computer-assisted telephone interview every 6 months. Starting with May 2009 follow-up, contingent on accelerometer availability, participants were invited to wear an accelerometer for 7 d. Device inventory was 1150. Accelerometer, instructions, log sheet, and stamped addressed return envelope were mailed to consenting participants. Postcard acknowledgement and reminders and two calls or less were made to encourage compliance.

RESULTS

Between May 2009 and January 2013, 20,076 were invited to participate; 12,146 (60.5%) consented. Participation rates by race-sex groups were similar: black women, 58.6%; black men, 59.6%; white women, 62.3%; and white men, 60.5%. The mean age of the 12,146 participants to whom devices were shipped was 63.5 ± 8.7 yr. Return rate was 92%. Of 11,174 returned, 1187 were not worn and 14 had device malfunction, and of 9973 with data, 8096 (81.2%) provided usable data, defined as ≥4 d of 10+ h of wear time, ranging from 74.4% among black women to 85.2% among white men.

CONCLUSIONS

Using mail and telephone methods, it is feasible to obtain objective measures of physical activity from a sizeable proportion of a national cohort of adults, with similar participation rates among blacks and whites. Linked with the clinical health information collected through follow-up, these data will allow future analyses on the association between objectively measured sedentary time, physical activity, and health outcomes.

Abstract WP293: Patient and Hospital Characteristics Associated With Assessing Stroke Patients for Rehabilitation During Acute Stroke Hospitalization: Findings From the National REGARDS Study

Background: “Assessment for rehabilitation” (AFR) is an acute stroke care quality measure that is included in clinical guideline recommendations. Previous reports from “Get With The Guidelines (GWTG)” and the Coverdell Registry have shown compliance rates as high as 90 to 94% in stroke patients. These studies showed that blacks, males, and older patients were more likely to receive AFR.

Methods: We abstracted data from ischemic stroke hospitalizations that occurred between 2003-2012 within REGARDS, a national US cohort study of blacks and whites aged > 45 at time of enrollment. The definition of AFR included any of the following: consult by rehab services, assessed by rehab team member, receipt of rehab during hospitalization. Independent patient and hospitalization characteristics associated with AFR were identified by logistic regression.

Results: Information on AFR was determined in 536 of 546 ischemic stroke hospitalizations. The median age was 73.8+ 8.6 years, 50% were women, 46.8% were black. Three-quarter of the patients (406/536) had AFR. In univariate analyses, participants who were older, black, those with higher modified Rankin Score (mRS) and those evaluated by a stroke team were more likely to be assessed for rehabilitation, while participants in the west region of the US were least likely to be assessed. After multivariable adjustment, those who were older, those with a higher mRS, and those evaluated by an acute stroke team remained more likely to be assessed, while there was no statistically significant association of race, sex, or region (Table).

Conclusions: The proportion of stroke patients assessed for rehabilitation was lower in this national sample compared to previous registry based reports. However these results corroborate prior findings that assessments are more common among older patients, blacks and those with more severe strokes. Further examination of patient and hospital characteristics is warranted.

Differences in the role of black race and stroke risk factors for first vs. recurrent stroke

OBJECTIVES

To assess whether black race and other cerebrovascular risk factors have a differential effect on first vs. recurrent stroke events.

METHODS

Estimate the differences in the magnitude of the association of demographic (age, back race, sex) or stroke risk factors (hypertension, diabetes, cigarette smoking, atrial fibrillation, left ventricular hypertrophy, or heart disease) for first vs. recurrent stroke from a longitudinal cohort study of 29,682 black or white participants aged 45 years and older.

RESULTS

Over an average 6.8 years follow-up, 301 of 2,993 participants with a previous stroke at baseline had a recurrent stroke, while 818 of 26,689 participants who were stroke-free at baseline had a first stroke. Among those stroke-free at baseline, there was an age-by-race interaction (p = 0.0002), with a first stroke risk 2.70 (95% confidence interval: 1.86-3.91) times greater for black than white participants at age 45, but no racial disparity at age 85 (hazard ratio = 0.91; 95% confidence interval: 0.70-1.18). In contrast, there was no evidence of a higher risk of recurrent stroke at any age for black participants (p > 0.05). The association of traditional stroke risk factors was generally similar for first and recurrent stroke.

CONCLUSION

The association of age and black race differs substantially on first vs. recurrent stroke risk, with risk factors playing a similar role.

Stroke Symptoms as a Predictor of Future Hospitalization

BACKGROUND

Stroke symptoms in the general adult population are common and associated with stroke risk factors, lower physical and mental functioning, impaired cognitive status, and future stroke. Our objective was to determine the association of stroke symptoms with self-reported hospitalization or emergency department (ED) visit.

METHODS

Lifetime history of stroke symptoms (sudden weakness, numbness, unilateral or general loss of vision, loss of ability to communicate or understand) was assessed at baseline in a national, population-based, longitudinal cohort study of 30,239 blacks and whites younger than 45 years, enrolled from 2003 to 2007. Self-reported hospitalization or ED visit and reason were collected during follow-up through March 2013. The symptom-hospitalization association was assessed by proportional hazards analysis in persons who were stroke/transient ischemic attack-free at baseline (27,126) with adjustment for sociodemographics and further adjustment for risk factors.

RESULTS

One or more stroke symptoms were reported by 4758 (17.5%). After adjustment for sociodemographics, stroke symptoms were most strongly associated with greater risk of hospitalization/ED for cardiovascular disease (CVD) (hazard ratio [HR] = 1.87, 95% confidence interval [CI]: 1.78-1.96), stroke (HR = 1.69, 95% CI: 1.55-1.85), and any reason (HR = 1.39, 95% CI: 1.34-1.44). These associations remained significant and only modestly reduced after risk factor adjustment.

CONCLUSIONS

Stroke symptoms are a marker for future hospitalization and ED visit not only for stroke but also for CVD in general. Findings suggest a role for stroke symptom assessment as a novel and simple approach for identifying individuals at high risk for CVD including stroke in whom preventive strategies could be implemented.

Characteristics and prognosis of acute myocardial infarction by discharge diagnosis: the Reasons for Geographic and Racial Differences in Stroke study

PURPOSE

To compare the characteristics and prognosis of acute myocardial infarctions (AMIs) that were not the primary reason for hospitalization, and thus not primary discharge diagnosis, to AMIs that were the primary reason for hospitalization.

METHODS

Primary discharge diagnoses for Reasons for Geographic and Racial Differences in Stroke study participants (black and white men and women age ≥45 years) with adjudicated AMIs were categorized as "AMI" or "other". Cox models were used to compare mortality up to 5 years post-AMI between primary discharge diagnoses of AMI and other.

RESULTS

Of 871 AMIs, primary discharge diagnosis was not AMI in 550 (63%). When primary discharge diagnosis was not AMI, average troponin elevations were smaller and heart failure was more common. Adjusted for participant and hospitalization characteristics, all-cause, coronary heart disease, and cardiovascular disease mortality after AMI were similar between groups (hazard ratios [95% confidence intervals]: 1.08 [0.80-1.47]; 1.29 [0.76-2.18]; and 0.86 [0.58-1.27], respectively).

CONCLUSIONS

Studies limited to individuals with primary discharge diagnosis of AMI may underestimate the burden of AMI and exclude a group with elevated risk of all-cause, coronary heart disease, and cardiovascular disease mortality.

Abstract 149: Can Prevention of Risk Factors Pre-Stroke Reduce 30-Day Post-Stroke Mortality?

Introduction: Studies of short-term survival after stroke generally identify patients in the hospital, providing limited insights about the association between pre-stroke risk factors and outcomes. We hypothesized that pre-stroke risk factors will be related to 30-day case fatality.

Methods: We prospectively studied the association of Framingham Stroke Risk Score (FSRS) factors on 30-day mortality following incident ischemic stroke (IS) among 28,253 stroke-free participants, aged 45+ in REGARDS, a national population based cohort enrolled 2003-2007. Suspect IS events were physician-reviewed. Logistic regression evaluated the association of pre-stroke risk factors with 30-day case-fatality after adjustment for age, race, sex and region of country. The six FSRS factors (hypertension, diabetes, cigarette smoking, atrial fibrillation, left ventricular hypertrophy, heart disease) were considered as predictors of case-fatality (individually, as a composite FSRS, and cumulative number present).

Results: Of 792 incident IS events, 67 (8.5%) people died within 30-days. Age was strongly associated with case-fatality (p < 0.0001), with a strong association for oldest age groups relative to those <65 years (see table). Race, sex and region were not associated with case fatality. After adjustment for demographic factors, individual risk factors were positively but nonsignificantly associated with higher case fatality. Higher FSRS was associated with higher case fatality (test for trend p = 0.014), with increased fatality for the top two vs. the lowest tertile. Likewise, higher fatality was seen for those with more risk factors (test for trend p = 0.025), with a notable increase for those with 3+ cumulative risk factors.

Conclusions: Individuals with higher pre-stroke risk factor burden were more likely to have a higher 30-day mortality following infarction. Prevention of risk factors could reduce the incidence of stroke and improve mortality following stroke.

Validity of claims-based stroke algorithms in contemporary Medicare data: reasons for geographic and racial differences in stroke (REGARDS) study linked with medicare claims

BACKGROUND

The accuracy of stroke diagnosis in administrative claims for a contemporary population of Medicare enrollees has not been studied. We assessed the validity of diagnostic coding algorithms for identifying stroke in the Medicare population by linking data from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study to Medicare claims.

METHODS AND RESULTS

The REGARDS Study enrolled 30 239 participants ≥45 years in the United States between 2003 and 2007. Stroke experts adjudicated suspected strokes, using retrieved medical records. We linked data for participants enrolled in fee-for-service Medicare to claims files from 2003 through 2009. Using adjudicated strokes as the gold standard, we calculated accuracy measures for algorithms to identify incident and recurrent strokes. We linked data for 15 089 participants, among whom 422 participants had adjudicated strokes during follow-up. An algorithm using primary discharge diagnosis codes for acute ischemic or hemorrhagic stroke (International Classification of Diseases, Ninth Revision, Clinical Modification codes: 430, 431, 433.x1, 434.x1, 436) had a positive predictive value of 92.6% (95% confidence interval, 88.8%-96.4%), a specificity of 99.8% (99.6%-99.9%), and a sensitivity of 59.5% (53.8%-65.1%). An algorithm using only acute ischemic stroke codes (433.x1, 434.x1, 436) had a positive predictive value of 91.1% (95% confidence interval, 86.6%-95.5%), a specificity of 99.8% (99.7%-99.9%), and a sensitivity of 58.6% (52.4%-64.7%).

CONCLUSIONS

Claims-based algorithms to identify stroke in a contemporary Medicare cohort had high positive predictive value and specificity, supporting their use as outcomes for etiologic and comparative effectiveness studies in similar populations. These inpatient algorithms are unsuitable for estimating stroke incidence because of low sensitivity.

Abstract W MP108: Accuracy of Diagnoses in Contemporary Medicare Data: REGARDS Study Linked With Medicare Claims

Background: Administrative data such as Medicare data are commonly used for health services research and comparative effectiveness studies. These databases are readily available and a good source of long-term data on healthcare utilization and health outcomes in real-world settings. Outcomes are captured using diagnostic codes, but the evidence on the validity of these codes is scarce in contemporary Medicare data.

Methods: We linked the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study data using SSN, date of birth and sex to 2003-2009 Medicare claims. In addition to the events captured by REGARDS phone interviews, medical charts were pursued for Medicare-identified strokes not previously identified in REGRADS. Events were adjudicated by stroke specialists using the retrieved medical charts. Using all the adjudicated strokes as gold standard, we calculated the sensitivity, specificity, PPV and NPV of inpatient stroke algorithms with ICD-9-CM codes [430, 431, 433.x1, 434.x1, 436] in the primary discharge diagnosis.

Results: We successfully linked 15,089 REGARDS participants with mean age of 69.3, 52% female and 37% Black. We adjudicated 457 strokes, of which 48 were identified by claims only and not by interviews. The tested algorithms had high specificity (99.8-100%), PPV (88.6-90.5%) and NPV (98.9-99.9%), but low sensitivity (58.6-67.4%) (Table).

Conclusions: High specificity and PPV of our algorithms to identify strokes in contemporary Medicare populations support their use in etiological and comparative effectiveness studies. While our inpatient Medicare algorithms identified 12% extra cases of strokes, their usefulness for estimating stroke incidence or related healthcare utilizations is limited by their low sensitivity. Linking cohorts to Medicare data is feasible and should be considered to increase the completeness of follow-up. Further studies are needed to evaluate more sensitive Medicare algorithms.

Disparities in evaluation at certified primary stroke centers: reasons for geographic and racial differences in stroke

BACKGROUND AND PURPOSE

Evaluation at primary stroke centers (PSCs) has the potential to improve outcomes for patients with stroke. We looked for differences in evaluation at Joint Commission certified PSCs by race, education, income, and geography (urban versus nonurban; Southeastern Stroke Belt versus non-Stroke Belt).

METHODS

Community-dwelling, black and white participants from the national Reasons for Geographic And Racial Differences in Stroke (REGARDS) prospective population-based cohort were enrolled between January 2003 and October 2007. Participants were contacted at 6-month intervals for suspected stroke events. For suspected stroke events, it was determined whether the evaluating hospital was a certified PSC.

RESULTS

Of 1000 suspected strokes, 204 (20.4%) strokes were evaluated at a PSC. A smaller proportion of women than men (17.8% versus 23.0%; P=0.04), those with a previous stroke (15.1% versus 21.6%; P=0.04), those living in the Stroke Belt (14.7% versus 27.3%; P<0.001), and those in a nonurban area (9.1% versus 23.1%; P<0.001) were evaluated at a PSC. There were no differences by race, education, or income. In multivariable analysis, subjects were less likely to be evaluated at a PSC if they lived in a nonurban area (odds ratio, 0.39; 95% confidence interval, 0.22-0.67) or lived in the Stroke Belt (odds ratio, 0.54; 95% confidence interval, 0.38-0.77) or had a previous stroke (odds ratio, 0.46; 95% confidence interval, 0.27-0.78).

CONCLUSIONS

Disparities in evaluation by PSCs are predominately related to geographic factors but not to race, education, or low income. Despite an increased burden of cerebrovascular disease in the Stroke Belt, subjects there were less likely to be evaluated at certified hospitals.

Stroke after carotid stenting and endarterectomy in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST)

BACKGROUND

Stroke occurs more commonly after carotid artery stenting than after carotid endarterectomy. Details regarding stroke type, severity, and characteristics have not been reported previously. We describe the strokes that have occurred in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST).

METHODS AND RESULTS

CREST is a randomized, open-allocation, controlled trial with blinded end-point adjudication. Stroke was a component of the primary composite outcome. Patients who received their assigned treatment within 30 days of randomization were included. Stroke was adjudicated by a panel of board-certified vascular neurologists with secondary central review of clinically obtained brain images. Stroke type, laterality, timing, and outcome were reported. A periprocedural stroke occurred among 81 of the 2502 patients randomized and among 69 of the 2272 in the present analysis. Strokes were predominantly minor (81%, n=56), ischemic (90%, n=62), in the anterior circulation (94%, n=65), and ipsilateral to the treated artery (88%, n=61). There were 7 hemorrhages, which occurred 3 to 21 days after the procedure, and 5 were fatal. Major stroke occurred in 13 (0.6%) of the 2272 patients. The estimated 4-year mortality after stroke was 21.1% compared with 11.6% for those without stroke. The adjusted risk of death at 4 years was higher after periprocedural stroke (hazard ratio, 2.78; 95% confidence interval, 1.63-4.76).

CONCLUSIONS

Stroke, particularly severe stroke, was uncommon after carotid intervention in CREST, but stroke was associated with significant morbidity and was independently associated with a nearly 3-fold increased future mortality. The delayed timing of major and hemorrhagic stroke after revascularization suggests that these strokes may be preventable.

Self-report of stroke, transient ischemic attack, or stroke symptoms and risk of future stroke in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

BACKGROUND AND PURPOSE

History of stroke and transient ischemic attack (TIA) are documented risk factors for subsequent stroke and all-cause mortality. Recent reports suggest increased risk among those reporting stroke symptoms absent stroke or TIA. However, the relative magnitude of increased stroke risk has not been described across the symptomatic spectrum: (1) asymptomatic, (2) stroke symptoms (SS) only, (3) TIA, (4) distant stroke (DS), and (5) recent stroke (RS).

METHODS

Between 2003 and 2007, the REasons for Geographic And Racial Differences in Stroke (REGARDS) study enrolled 30 239 black and white Americans ≥45 years of age. DS and RS were defined as self-report of physician diagnosis of stroke >5 or <5 years before baseline, respectively. SS was defined as a history of any of 6 sudden onset stroke symptoms absent TIA/stroke diagnosis. Kaplan-Meier and proportional hazards analysis were used to contrast stroke risk differences.

RESULTS

Over 5.0±1.72 years of follow-up, 737 strokes were validated. Compared with asymptomatic persons, those with SS, TIA, DS, and RS all had increased risk of future stroke. After adjustment for age, race, sex, income, education, alcohol intake, current smoking, and a history of diabetes mellitus, hypertension, myocardial infarction, atrial fibrillation, and dyslipidemia, there was 1.20-fold (not statistically significant) increased stroke risk for SS (95% CI, 0.96-1.51), 1.73-fold for TIA (95% CI, 1.27-2.36), 2.23-fold for DS (95% CI, 1.61- 3.09), and 2.85-fold for RS (95% CI, 2.16-3.76).

CONCLUSIONS

Results suggest a spectrum of risk from stroke symptoms to TIA, DS, and RS, and imply a need for establishing these categories in health screenings to manage risk for future stroke, reinforcing the clinical importance of stroke history including the presence of stroke symptoms.

The effects of extended pre-quit varenicline treatment on smoking behavior and short-term abstinence: a randomized clinical trial

Preclinical research and learning theory suggest that a longer duration of varenicline treatment prior to the target quit date (TQD) would reduce smoking rates before cessation and improve abstinence outcomes. A double-blind randomized controlled trial tested this hypothesis in 60 smokers randomized to either an Extended run-in group (4 weeks of pre-TQD varenicline) or a Standard run-in group (3 weeks of placebo, 1 week of pre-TQD varenicline); all the participants received 11 weeks of post-TQD varenicline and brief counseling. During the pre-quit run-in, the reduction in smoking rates was greater in the Extended run-in group than in the Standard run-in group (42% vs. 24%, P < 0.01), and this effect was greater in women than in men (57% vs. 26%, P = 0.001). The rate of continuous abstinence during the final 4 weeks of treatment was higher among women in the Extended group compared to women in the Standard run-in group (67% vs. 35%). Although these data suggest that extension of varenicline treatment reduces smoking during the pre-quit period and may further enhance cessation rates, confirmatory evidence is needed from phase III clinical trials.

Traditional risk factors as the underlying cause of racial disparities in stroke: lessons from the half-full (empty?) glass

BACKGROUND AND PURPOSE

Black/white disparities in stroke incidence are well documented, but few studies have assessed the contributions to the disparity. Here we assess the contribution of "traditional" risk factors.

METHODS

A total of 25 714 black and white men and women, aged≥45 years and stroke-free at baseline, were followed for an average of 4.4 years to detect stroke. Mediation analysis using proportional hazards analysis assessed the contribution of traditional risk factors to racial disparities.

RESULTS

At age 45 years, incident stroke risk was 2.90 (95% CI: 1.72-4.89) times more likely in blacks than in whites and 1.66 (95% CI: 1.34-2.07) times at age 65 years. Adjustment for risk factors attenuated these excesses by 40% and 45%, respectively, resulting in relative risks of 2.14 (95% CI: 1.25-3.67) and 1.35 (95% CI: 1.08-1.71). Approximately one half of this mediation is attributable to systolic blood pressure. Further adjustment for socioeconomic factors resulted in total mediation of 47% and 53% to relative risks of 2.01 (95% CI: 1.16-3.47) and 1.30 (1.03-1.65), respectively.

CONCLUSIONS

Between ages 45 to 65 years, approximately half of the racial disparity in stroke risk is attributable to traditional risk factors (primarily systolic blood pressure) and socioeconomic factors, suggesting a critical need to understand the disparity in the development of these traditional risk factors. Because half of the excess stroke risk in blacks is not attributable to traditional risk factors and socioeconomic factors, differential impact of risk factors, residual confounding, or nontraditional risk factors may also play a role.

Disparities in stroke incidence contributing to disparities in stroke mortality

OBJECTIVE

While black-white and regional disparities in U.S. stroke mortality rates are well documented, the contribution of disparities in stroke incidence is unknown. We provide national estimates of stroke incidence by race and region, contrasting these to publicly available stroke mortality data.

METHODS

This analysis included 27,744 men and women without prevalent stroke (40.4% black), aged ≥45 years from the REasons for Geographic And Racial Differences in Stroke (REGARDS) national cohort study, enrolled 2003-2007. Incident stroke was defined as first occurrence of stroke over 4.4 years of follow-up. Age-sex-adjusted stroke mortality rates were calculated using data from the Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiological Research (WONDER) System.

RESULTS

There were 460 incident strokes over 113,469 person-years of follow-up. Relative to the rest of the United States, incidence rate ratios (IRRs) of stroke in the southeastern stroke belt and stroke buckle were 1.06 (95% confidence interval [CI], 0.87-1.29) and 1.19 (95% CI, 0.96-1.47), respectively. The age-sex-adjusted black/white IRR(black) was 1.51 (95% CI, 1.26-1.81), but for ages 45-54 years the IRR(black) was 4.02 (95% CI, 1.23-13.11) while for ages 85+ it was 0.86 (95% CI, 0.33-2.20). Generally, the IRRs(black) were less than the mortality rate ratios (MRRs) across age groups; however, only in ages 55-64 years and 65-74 years did the 95% CIs of IRRs(black) not include the MRR(black) . The MRRs for regions were within 95% CIs for IRRs.

INTERPRETATION

National patterns of black-white and regional differences in stroke incidence are similar to those for stroke mortality; however, the magnitude of differences in incidence appear smaller.

Race and gender differences in 1-year outcomes for community-dwelling stroke survivors with family caregivers

BACKGROUND AND PURPOSE

Previous research has reported worse outcomes after stroke for women and for African Americans, but few prospective population-based studies have systematically examined demographic differences on long-term stroke outcomes. Race and gender differences in 1-year stroke outcomes were examined using an epidemiologically derived sample of first-time stroke survivors from the national REasons for Geographic and Racial Differences in Stroke (REGARDS) study.

METHODS

Participants of REGARDS who reported a first-time stroke event during regular surveillance calls were interviewed by telephone and then completed an in-home evaluation approximately 1 year after the verified first-time stroke event (N=112). A primary family caregiver was also enrolled and interviewed for each stroke survivor. Measures from the in-home evaluation included previously validated stroke outcomes assessments of neurological deficits, functional impairments, and patient-reported effects of stroke in multiple domains. Results- African American stroke survivors were less likely to be living with their primary family caregivers than white participants. Analyses that controlled for age, education, and whether the stroke survivors lived with their primary family caregivers indicated that African Americans and women showed significantly greater deficits on multiple 1-year outcome measures compared to whites and men, respectively.

CONCLUSIONS

Among community-dwelling stroke survivors with family caregivers, women and African Americans are at heightened risk for poor long-term outcomes 1 year after first-time stroke events. Rehabilitation services and public health policies aimed at enhancing stroke recovery rates should address these disparities in poststroke outcomes.

Histidine nutrition and genotype affect cataract development in Atlantic salmon, Salmo salar L

The aim of this study was to investigate effects of dietary levels of histidine (His) and iron (Fe) on cataract development in two strains of Atlantic salmon monitored through parr-smolt transformation. Three experimental diets were fed: (i) a control diet (CD) with 110 mg kg(-1) Fe and 11.7 g kg(-1) His; (ii) CD supplemented with crystalline His to a level of 18 g kg(-1) (HD); and (iii) HD with added iron up to 220 mg kg(-1) (HID). A cross-over design, with two feeding periods was used. A 6-week freshwater (FW) period was followed by a 20-week period, of which the first three were in FW and the following 17 weeks in sea water (SW). Fish were sampled for weighing, cataract assessment and tissue analysis at five time points. Cataracts developed in all groups in SW, but scores were lower in those fed high His diets (P < 0.05). This effect was most pronounced when HD or HID was given in SW, but was also observed when these diets were given in FW only. Histidine supplementation had a positive effect on growth performance and feed conversion ratio (P < 0.05), whereas this did not occur when iron was added. Groups fed HD or HID had higher lens levels of His and N-acetyl histidine (NAH), the latter showing a marked increase post-smoltification (P < 0.05). The HD or HID groups also showed higher muscle concentrations of the His dipeptide anserine (P < 0.05). There was a strong genetic influence on cataract development in the CD groups (P < 0.001), not associated with tissue levels of His or NAH. The role of His and His-related compounds in cataractogenesis is discussed in relation to tissue buffering, osmoregulation and antioxidation.

Expression of a protein tyrosine phosphatase in normal and v-src-transformed mouse 3T3 fibroblasts

A rat cDNA encoding a 51-kD protein tyrosine phosphatase (PTP1) was cloned into a mammalian expression vector and transfected into normal and v-src-transformed mouse NIH 3T3 fibroblasts. In the stable subclones isolated, PTP1 expression at the mRNA level was elevated twofold to 25-fold. The highest constitutive level of phosphotyrosine- specific dephosphorylating activity observed without cytotoxic effects or significant clonal instability was approximately 10-fold over the endogenous activity. The expressed PTP1 was found to be associated with the particulate fraction of the fibroblasts. Subcellular fractionation and immunofluorescent microscopic examination of PTP1-overexpressing cells has shown the phosphatase to be localized to the reticular network of the ER. PTP1 was readily solubilized by detergents, but not by high salt. Limited proteolysis of membrane-associated PTP1 resulted in the release of lower molecular mass (48 and 37 kD) forms of the enzyme to the cytosol. Thermal phase partitioning of isolated membranes with Triton X-114 indicated that the full-length PTP1 was strongly integrated into the membrane in contrast to the proteolytically derived fragments of PTP1. Overexpression of PTP1 caused little apparent change in the rate of cell proliferation, but did induce changes in fibroblast morphology. A substantial increase in the proportion of bi- and multinucleate cells in PTP1-expressing cell populations was observed, and, in the case of the v-src-transformed cells, cell flattening and loss of refractibility occurred. Although no apparent difference in the tyrosine phosphorylation of pp60v-src was noted in v-src-transformed control and PTP1-overexpressing fibroblasts, the phosphotyrosine content of a 70-kD polypeptide was decreased in PTP1-overexpressing cells.

Characterization of the carboxyl-terminal sequences responsible for protein retention in the endoplasmic reticulum

The COOH-terminal sequence KDEL has been shown to be essential for the retention of several proteins in the lumen of the endoplasmic reticulum (Munro S., and Pelham, H. R. B. (1987) Cell 48, 899-907; Pelham, H. R. B. (1988) EMBO J. 7, 913-918; Mazzarella; R. A., Srinivasan, M., Haugejorden, S. M., and Green, M. (1990) J. Biol. Chem. 265, 1092-1101). We have previously demonstrated that variants to the KDEL retention signal, particularly at the initial two positions of the tetrapeptide, can be made without affecting its ability to direct intracellular retention when appended to the neuropeptide Y precursor (pro-NPY) (Andres, D. A., Dickerson, I. M., and Dixon, J. E. (1990) J. Biol. Chem. 265, 5952-5955). To further investigate the nature of the KDEL retention signal, oligonucleotide-directed mutagenesis and transfection was used to generate stable mouse anterior pituitary AtT-20 cell lines expressing pro-NPY mutants with variants of the KDEL sequence added to their direct carboxyl terminus. Analyses of dibasic processing and indirect immunofluorescent microscopy of AtT-20 subclones were consistent with the retention of the pro-NPY mutants bearing the COOH-terminal extensions QDEL, KEDL, or KDEI within the endoplasmic reticulum. A change in the final amino acid of the tetrapeptide from Leu to Val abolished retention completely, and the peptide hormone was processed and secreted. These results indicate that only a limited number of conservative changes can be made to the final two positions of the tetrapeptide without abolishing activity and suggest a highly specific interaction of the retention signal and the KDEL receptor.