Compliance-Adjusted Estimates of Aspirin Effects Among Older Persons in the ASPREE Randomized Trial

The Aspirin in Reducing Events in the Elderly (ASPREE) Trial recruited 19,114 participants across Australia and the United States during 2010-2014. Participants were randomized to receive either 100 mg of aspirin daily or matching placebo, with disability-free survival as the primary outcome. During a median 4.7 years of follow-up, 37% of participants in the aspirin group permanently ceased taking their study medication and 10% commenced open-label aspirin use. In the placebo group, 35% and 11% ceased using study medication and commenced open-label aspirin use, respectively. In order to estimate compliance-adjusted effects of aspirin, we applied rank-preserving structural failure time models. The results for disability-free survival and most secondary endpoints were similar in intention-to-treat and compliance-adjusted analyses. For major hemorrhage, cancer mortality, and all-cause mortality, compliance-adjusted effects of aspirin indicated greater risks than were seen in intention-to-treat analyses. These findings were robust in a range of sensitivity analyses. In accordance with the original trial analyses, compliance-adjusted results showed an absence of benefit with aspirin for primary prevention in older people, along with an elevated risk of clinically significant bleeding.

Health Characteristics and Aspirin Use in Participants at the Baseline of the ASPirin in Reducing Events in the Elderly - eXTension (ASPREE-XT) Observational Study

BACKGROUND

Aspirin as a primary preventative in healthy older adults did not prolong disability-free survival in the ASPREE randomized trial. Observational studies following randomized trials allow assessment of benefits and harms which may not appear during the trial. We describe health characteristics, physical function, and aspirin use in the ASPREE-eXTension (ASPREE-XT) observational study cohort.

METHODS

Descriptive statistics compared health characteristics of those consented to ASPREE-XT at their first post-trial baseline (XT01) to corresponding ASPREE baseline values, and to those not consented. Likelihood of an indication for aspirin was assessed in participants reporting aspirin use at XT01.

RESULTS

16,317 (93%) of the remaining and eligible 17,546 ASPREE participants were consented into ASPREE-XT; 14,894 completed XT01. Mean participant age had increased from 74.9 to 80.6 years. Overall health and physical function declined from the original ASPREE baseline; more participants were living alone, there was higher prevalence of chronic kidney disease, diabetes, and frailty, grip strength was lower and gait speed slower. Those not consented into ASPREE-XT were slightly older, and had lower cognitive scores and higher prevalence of age-related conditions than those who continued. 1015/11,717 (8.7%) participants without an apparent indication for aspirin reported using aspirin at XT01.

CONCLUSIONS

The ASPREE-XT cohort was slightly less healthy at the XT01 visit than at ASPREE trial initiation, and rates of aspirin use without indication were similar to ASPREE baseline. Participants will be followed long-term to investigate aspirin's potential legacy towards dementia and cancer prevention and explore determinants of healthy aging.

602Prevalence of cancer history and association with risk factors in a healthy older population

Background

The ASPirin in Reducing Events in the Elderly (ASPREE) study randomised healthy older individuals to 100mg aspirin or placebo, with clinical outcomes and disability-free survival endpoints. Detailed baseline data provides a rare opportunity to explore cancer burden and association with known cancer risk factors in this population.

Methods

At enrolment (2010-2014), self-reported personal cancer history, cancer type and cancer risk factor data were sought from 19,114 participants (Australia, n = 16,703; U.S., n = 2,411). Participants were healthy and expected to survive 5 years.

Results

Of those reporting a prior cancer diagnosis (18% women, 22% men), women were diagnosed younger (16% vs 6% of diagnoses <50 years). Cancer prevalence increased with age. Prostate and breast cancer history were higher in U.S. participants; melanoma and colorectal cancer were higher in Australian participants. Cancer history prevalence was not associated with any common risk factors, but was associated with poor health ratings in men. Blood and breast cancer history was more common with past aspirin use.

Conclusions

Personal cancer history in healthy older ASPREE participants was as expected for the most common cancer types in the respective populations. The lack of alignment with known risk factors is attributable to survivor bias, driven by entry criteria, and to possible molecular differences in cancer between elderly and younger people.

Key messages

As the prevalence of cancer increases with age, the lack of alignment with known risk factors implies other factors play a significant role.

Effect of Aspirin on Cancer Incidence and Mortality in Older Adults

Background

ASPirin in Reducing Events in the Elderly, a randomized, double-blind, placebo-controlled trial of daily low-dose aspirin (100 mg) in older adults, showed an increase in all-cause mortality, primarily due to cancer. In contrast, prior randomized controlled trials, mainly involving younger individuals, demonstrated a delayed cancer benefit with aspirin. We now report a detailed analysis of cancer incidence and mortality.

Methods

19 114 Australian and US community-dwelling participants aged 70 years and older (US minorities 65 years and older) without cardiovascular disease, dementia, or physical disability were randomly assigned and followed for a median of 4.7 years. Fatal and nonfatal cancer events, a prespecified secondary endpoint, were adjudicated based on clinical records.

Results

981 cancer events occurred in the aspirin and 952 in the placebo groups. There was no statistically significant difference between groups for all incident cancers (hazard ratio [HR] = 1.04, 95% confidence interval [CI] = 0.95 to 1.14), hematological cancer (HR = 0.98, 95% CI = 0.73 to 1.30), or all solid cancers (HR = 1.05, 95% CI = 0.95 to 1.15), including by specific tumor type. However, aspirin was associated with an increased risk of incident cancer that had metastasized (HR = 1.19, 95% CI = 1.00 to 1.43) or was stage 4 at diagnosis (HR = 1.22, 95% CI = 1.02 to 1.45), and with higher risk of death for cancers that presented at stages 3 (HR = 2.11, 95% CI = 1.03 to 4.33) or 4 (HR = 1.31, 95% CI = 1.04 to 1.64).

Conclusions

In older adults, aspirin treatment had an adverse effect on later stages of cancer evolution. These findings suggest that in older persons, aspirin may accelerate the progression of cancer and, thus, suggest caution with its use in this age group.

Cancer history and risk factors in healthy older people enrolling in the ASPREE clinical trial

BACKGROUND

Cancer is a leading cause of death globally. Given the elevated risk of cancer with age and an ageing population, it is important to understand the changing burden of cancer in older populations. The ASPirin in Reducing Events in the Elderly (ASPREE) study randomised healthy older individuals to 100 mg aspirin or placebo, with clinical outcomes and disability-free survival endpoints. Detailed baseline data provides a rare opportunity to explore cancer burden in a uniquely healthy older population.

METHODS

At study enrolment (2010-2014), self-reported personal cancer history, cancer type and cancer risk factor data were sought from 19,114 participants (Australia, n = 16,703; U.S., n = 2411). Eligible participants were healthy, free of major diseases and expected to survive 5 years.

RESULTS

Nearly 20% of enrolling ASPREE participants reported a prior cancer diagnosis; 18% of women and 22% of men, with women diagnosed younger (16% vs 6% of diagnoses <50 years). Cancer prevalence increased with age. Prevalence of prostate and breast cancer history were higher in U.S. participants; melanoma and colorectal cancer were higher in Australian participants. Cancer history prevalence was not associated with contemporary common risk factors nor previous aspirin use, but was associated with poor health ratings in men. Blood and breast cancer history were more common with past aspirin use.

CONCLUSIONS

Personal cancer history in healthy older ASPREE participants was as expected for the most common cancer types in the respective populations, but was not necessarily aligned with known risk factors. We attribute this to survivor bias, likely driven by entry criteria.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number Register (ISRCTN83772183) and clinicaltrials.gov (NCT01038583).

Randomized placebo-controlled trial of the effects of aspirin on dementia and cognitive decline

OBJECTIVE

To determine the effect of low-dose aspirin vs placebo on incident all-cause dementia, incident Alzheimer disease (AD), mild cognitive impairment (MCI), and cognitive decline in older individuals.

METHODS

Aspirin in Reducing Events in the Elderly (ASPREE) was a double-blind, placebo-controlled trial of low-dose aspirin. In the United States and Australia, community-dwelling individuals aged ≥70 years (US minorities ≥65 years) and free of cardiovascular disease, physical disability, and diagnosed dementia were enrolled. Participants were randomized 1:1-100 mg daily aspirin or placebo. The Modified Mini-Mental State Examination, Hopkins Verbal Learning Test-Revised, Symbol Digit Modalities Test, and Controlled Oral Word Association Test assessed cognition at baseline and over follow-up. Additional cognitive testing was performed in participants with suspected dementia ("trigger") based on within-study assessments or clinical history. Dementia was adjudicated according to DSM-IV criteria. National Institute on Aging-Alzheimer's Association criteria were used for AD and MCI subclassification.

RESULTS

A total of 19,114 participants were followed over a median 4.7 years and 964 triggered further dementia assessments. There were 575 adjudicated dementia cases, and 41% were classified as clinically probable AD. There was no substantial difference in the risk of all dementia triggers (hazard ratio [HR], 1.03; 95% confidence interval [CI], 0.91-1.17), probable AD (HR, 0.96; 95% CI, 0.74-1.24), or MCI (HR, 1.12; 95% CI, 0.92-1.37) between aspirin and placebo. Cognitive change over time was similar in the aspirin and placebo groups.

CONCLUSIONS

There was no evidence that aspirin was effective in reducing risk of dementia, MCI, or cognitive decline. Follow-up of these outcomes after initial exposure is ongoing.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for healthy older individuals, low-dose aspirin does not significantly reduce the incidence of dementia, probable AD, MCI, or cognitive decline.

CLINICALTRIALSGOV IDENTIFIER

NCT01038583.

The COronavirus Pandemic Epidemiology (COPE) Consortium: A Call to Action

The rapid pace of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; COVID-19) pandemic presents challenges to the real-time collection of population-scale data to inform near-term public health needs as well as future investigations. We established the COronavirus Pandemic Epidemiology (COPE) consortium to address this unprecedented crisis on behalf of the epidemiology research community. As a central component of this initiative, we have developed a COVID Symptom Study (previously known as the COVID Symptom Tracker) mobile application as a common data collection tool for epidemiologic cohort studies with active study participants. This mobile application collects information on risk factors, daily symptoms, and outcomes through a user-friendly interface that minimizes participant burden. Combined with our efforts within the general population, data collected from nearly 3 million participants in the United States and United Kingdom are being used to address critical needs in the emergency response, including identifying potential hot spots of disease and clinically actionable risk factors. The linkage of symptom data collected in the app with information and biospecimens already collected in epidemiology cohorts will position us to address key questions related to diet, lifestyle, environmental, and socioeconomic factors on susceptibility to COVID-19, clinical outcomes related to infection, and long-term physical, mental health, and financial sequalae. We call upon additional epidemiology cohorts to join this collective effort to strengthen our impact on the current health crisis and generate a new model for a collaborative and nimble research infrastructure that will lead to more rapid translation of our work for the betterment of public health.

Overcoming challenges to data quality in the ASPREE clinical trial

Background

Large-scale studies risk generating inaccurate and missing data due to the complexity of data collection. Technology has the potential to improve data quality by providing operational support to data collectors. However, this potential is under-explored in community-based trials. The Aspirin in reducing events in the elderly (ASPREE) trial developed a data suite that was specifically designed to support data collectors: the ASPREE Web Accessible Relational Database (AWARD). This paper describes AWARD and the impact of system design on data quality.

Methods

AWARD’s operational requirements, conceptual design, key challenges and design solutions for data quality are presented. Impact of design features is assessed through comparison of baseline data collected prior to implementation of key functionality (n = 1000) with data collected post implementation (n = 18,114). Overall data quality is assessed according to data category.

Results

At baseline, implementation of user-driven functionality reduced staff error (from 0.3% to 0.01%), out-of-range data entry (from 0.14% to 0.04%) and protocol deviations (from 0.4% to 0.08%). In the longitudinal data set, which contained more than 39 million data values collected within AWARD, 96.6% of data values were entered within specified query range or found to be accurate upon querying. The remaining data were missing (3.4%). Participant non-attendance at scheduled study activity was the most common cause of missing data. Costs associated with cleaning data in ASPREE were lower than expected compared with reports from other trials.

Conclusions

Clinical trials undertake complex operational activity in order to collect data, but technology rarely provides sufficient support. We find the AWARD suite provides proof of principle that designing technology to support data collectors can mitigate known causes of poor data quality and produce higher-quality data. Health information technology (IT) products that support the conduct of scheduled activity in addition to traditional data entry will enhance community-based clinical trials. A standardised framework for reporting data quality would aid comparisons across clinical trials.

Trial registration

International Standard Randomized Controlled Trial Number Register, ISRCTN83772183. Registered on 3 March 2005.

Prevalence of depressive symptoms and its associated factors among healthy community-dwelling older adults living in Australia and the United States

OBJECTIVE

This study was conducted to estimate prevalence rates and factors associated with depressive symptoms indexed by the Centre for Epidemiological Studies-Depression (CES-D-10) score in a large sample of community-dwelling healthy older adults from Australia and the United States. Convergent and divergent validity of the CES-D-10 were also examined.

METHODS

A total of 19 114 individuals aged greater than or equal to 65 years old were enrolled from a primary prevention clinical trial. Depressive symptoms were classified using the CES-D-10 score greater than or equal to 8 and greater than or equal to 10. Gender-specific prevalence for subgroups according to sociodemographic characteristics were reported, and factors associated with depressive symptoms were estimated.

RESULTS

The overall prevalence rates of depressive symptoms were 9.8%, 95% CI, 8.5-11.2 and 5.0%, 95% CI, 4.0-6.0, according to the CES-D-10 score greater than or equal to 8 and greater than or equal to 10, respectively. Depressive symptoms were more common in women, individuals with less than 12 years of education, those living alone or in a residential care, ethnic minorities, current smokers, and former alcohol users. Convergent and divergent validities of the CES-D-10 were confirmed by observing strong negative association with the SF-12 mental health component and a modest negative association with SF-12 physical component, respectively.

CONCLUSIONS

This study reports the prevalence of depressive symptoms in Australian and US community-dwelling healthy older populations. These findings emphasize the high burden of the condition and factors associated with depressive symptoms, to better inform clinicians and help with early detection and treatment of depression in this age group.

Quality of Life for 19,114 participants in the ASPREE (ASPirin in Reducing Events in the Elderly) study and their association with sociodemographic and modifiable lifestyle risk factors

PURPOSE

To explore the relationship between sociodemographic and lifestyle variables with health-related quality of life (HRQoL) of a large cohort of 'healthy' older individuals.

METHODS

The sample included individuals aged 65+ years from Australia (N = 16,703) and the USA (N = 2411) enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) multicentre placebo-controlled trial study and free of cardiovascular disease, dementia, serious physical disabilities or 'fatal' illnesses. The associations with the physical (PCS) and mental component scores (MCS) of HRQoL (SF-12 questionnaire) were explored using multiple linear regression models from data collected at baseline (2010-2014).

RESULTS

The adjusted PCS mean was slightly higher in the USA (49.5 ± 9.1) than Australia (48.2 ± 11.6; p < 0.001), but MCS was similar in both samples (55.7 ± 7.5 and 55.7 ± 9.6, respectively; p = 0.603). Males, younger participants, better educated, more active individuals, or those currently drinking 1-2 alcoholic drinks/day showed a better HRQoL (results more evident for PCS than MCS), while current heavy smokers had the lowest physical HRQoL in both countries. Neither age, walking time, nor alcohol intake was associated with MCS in either cohort.

CONCLUSIONS

Baseline HRQoL of ASPREE participants was higher than that reported in population-based studies of older individuals, but the associations between sociodemographic and lifestyle variables were consistent with the published literature. As the cohort ages and develops chronic diseases, ASPREE will be able to document HRQoL changes.

Effect of Aspirin on All-Cause Mortality in the Healthy Elderly

BACKGROUND

In the primary analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial, now published in the Journal, we report that the daily use of aspirin did not provide a benefit with regard to the primary end point of disability-free survival among older adults. A numerically higher rate of the secondary end point of death from any cause was observed with aspirin than with placebo.

METHODS

From 2010 through 2014, we enrolled community-dwelling persons in Australia and the United States who were 70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, or disability. Participants were randomly assigned to receive 100 mg of enteric-coated aspirin or placebo. Deaths were classified according to the underlying cause by adjudicators who were unaware of trial-group assignments. Hazard ratios were calculated to compare mortality between the aspirin group and the placebo group, and post hoc exploratory analyses of specific causes of death were performed.

RESULTS

Of the 19,114 persons who were enrolled, 9525 were assigned to receive aspirin and 9589 to receive placebo. A total of 1052 deaths occurred during a median of 4.7 years of follow-up. The risk of death from any cause was 12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group (hazard ratio, 1.14; 95% confidence interval [CI], 1.01 to 1.29). Cancer was the major contributor to the higher mortality in the aspirin group, accounting for 1.6 excess deaths per 1000 person-years. Cancer-related death occurred in 3.1% of the participants in the aspirin group and in 2.3% of those in the placebo group (hazard ratio, 1.31; 95% CI, 1.10 to 1.56).

CONCLUSIONS

Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number, NCT01038583 .).

Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly

BACKGROUND

Aspirin is a well-established therapy for the secondary prevention of cardiovascular events. However, its role in the primary prevention of cardiovascular disease is unclear, especially in older persons, who have an increased risk.

METHODS

From 2010 through 2014, we enrolled community-dwelling men and women in Australia and the United States who were 70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, or disability. Participants were randomly assigned to receive 100 mg of enteric-coated aspirin or placebo. The primary end point was a composite of death, dementia, or persistent physical disability; results for this end point are reported in another article in the Journal. Secondary end points included major hemorrhage and cardiovascular disease (defined as fatal coronary heart disease, nonfatal myocardial infarction, fatal or nonfatal stroke, or hospitalization for heart failure).

RESULTS

Of the 19,114 persons who were enrolled in the trial, 9525 were assigned to receive aspirin and 9589 to receive placebo. After a median of 4.7 years of follow-up, the rate of cardiovascular disease was 10.7 events per 1000 person-years in the aspirin group and 11.3 events per 1000 person-years in the placebo group (hazard ratio, 0.95; 95% confidence interval [CI], 0.83 to 1.08). The rate of major hemorrhage was 8.6 events per 1000 person-years and 6.2 events per 1000 person-years, respectively (hazard ratio, 1.38; 95% CI, 1.18 to 1.62; P<0.001).

CONCLUSIONS

The use of low-dose aspirin as a primary prevention strategy in older adults resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number, NCT01038583 .).

Effect of Aspirin on Disability-free Survival in the Healthy Elderly

BACKGROUND

Information on the use of aspirin to increase healthy independent life span in older persons is limited. Whether 5 years of daily low-dose aspirin therapy would extend disability-free life in healthy seniors is unclear.

METHODS

From 2010 through 2014, we enrolled community-dwelling persons in Australia and the United States who were 70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, or physical disability. Participants were randomly assigned to receive 100 mg per day of enteric-coated aspirin or placebo orally. The primary end point was a composite of death, dementia, or persistent physical disability. Secondary end points reported in this article included the individual components of the primary end point and major hemorrhage.

RESULTS

A total of 19,114 persons with a median age of 74 years were enrolled, of whom 9525 were randomly assigned to receive aspirin and 9589 to receive placebo. A total of 56.4% of the participants were women, 8.7% were nonwhite, and 11.0% reported previous regular aspirin use. The trial was terminated at a median of 4.7 years of follow-up after a determination was made that there would be no benefit with continued aspirin use with regard to the primary end point. The rate of the composite of death, dementia, or persistent physical disability was 21.5 events per 1000 person-years in the aspirin group and 21.2 per 1000 person-years in the placebo group (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11; P=0.79). The rate of adherence to the assigned intervention was 62.1% in the aspirin group and 64.1% in the placebo group in the final year of trial participation. Differences between the aspirin group and the placebo group were not substantial with regard to the secondary individual end points of death from any cause (12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group), dementia, or persistent physical disability. The rate of major hemorrhage was higher in the aspirin group than in the placebo group (3.8% vs. 2.8%; hazard ratio, 1.38; 95% CI, 1.18 to 1.62; P<0.001).

CONCLUSIONS

Aspirin use in healthy elderly persons did not prolong disability-free survival over a period of 5 years but led to a higher rate of major hemorrhage than placebo. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number, NCT01038583 .).

Normative performance of healthy older individuals on the Modified Mini-Mental State (3MS) examination according to ethno-racial group, gender, age, and education level

OBJECTIVE

To present normative performance data on the Modified Mini-Mental State (3MS) examination for healthy community-dwelling older individuals according to gender, age, education level, and ethno-racial group.

METHOD

More than 19,000 generally healthy older men and women without a diagnosis of dementia were recruited from the general population in Australia and the U.S. for the ASPirin in Reducing Events in the Elderly (ASPREE) study. The 3MS exam was administered as part of the baseline screening and individuals scoring above 77 were eligible to participate.

RESULTS

The sample comprised 16,360 Australian whites, 1080 U.S. whites, 895 African-Americans and 316 Hispanic/Latinos. The median age of participants was 74 years (range 65-98), with an average of 12 years of education and 56% were female. Increasing age and fewer years of completed education were associated with lower scores on the 3MS. Women scored higher than men in most age and education categories. Differences across ethno-racial groups were found. With factor analysis, four factors were identified which accounted for 35% of the between-person variance in 3MS scores for white Australians.

CONCLUSIONS

This large cohort of older individuals provides some of the most comprehensive 3MS normative data to be generated for whites (Australian and U.S.), Hispanic/Latinos and African-Americans, by age, gender, and educational attainment. These findings will serve as important reference standards for monitoring cognitive function in generally healthy older individuals, becoming increasingly important as this fraction of the population increases.

Psychometric properties of a short form of the Center for Epidemiologic Studies Depression (CES-D-10) scale for screening depressive symptoms in healthy community dwelling older adults

BACKGROUND

The 10-item Center for the Epidemiological Studies of Depression Short Form (CES-D-10) is a widely used self-report measure of depression symptomatology. The aim of this study is to investigate the psychometric properties of the CES-D-10 in healthy community dwelling older adults.

METHODS

The sample consists of 19,114 community-based individuals residing in Australia and the United States who participated in the ASPREE trial baseline assessment. All individuals were free of any major illness at the time. We evaluated construct validity by performing confirmatory factor analysis, examined measurement invariance across country and gender followed by evaluating item discrimination bias in age, gender, race, ethnicity and education level, and assessing internal consistency.

RESULTS

High item-total correlations and Cronbach's alpha indicated high internal consistency. The factor analyses suggested a unidimensional factor structure. Construct validity was supported in the overall sample, and by country and gender sub-groups. The CES-D-10 was invariant across countries, and although evidence of marginal gender non-invariance was observed there was no evidence of notable gender specific item discrimination bias. No notable differences in discrimination parameters or group membership measurement non-invariance were detected by gender, age, race, ethnicity, and education level.

CONCLUSION

These findings suggest the CES-D-10 is a reliable and valid measure of depression in a volunteer sample. No noteworthy evidence of invariance and/or item discrimination bias is observed across gender, age, race, language and ethnic groups.

The aspirin in reducing events in the elderly trial: Statistical analysis plan

Rationale Aspirin has positive and negative effects on a number of age-related chronic conditions and there is uncertainty regarding its role in primary prevention in people aged 70 years and over. Aims To assess whether daily active treatment of 100 mg enteric-coated aspirin will extend the duration of disability-free life in healthy older participants. Design A double-blind, randomized, placebo-controlled primary prevention trial undertaken in Australia and the United States with careful adjudication of endpoints including stroke. Study outcome In Australia 16,703 individuals were recruited through general practices across five states and territories, and in the United States, 2411 participants were recruited through 34 clinical sites across the country. Follow-up of participants will finish at the end of 2017 with average follow-up exceeding 4.25 years per person. Discussion The statistical analysis plan for ASPREE, finalized after closure of recruitment but before the end of patient follow-up, outlines the primary analyses and a range of subgroup and sensitivity analyses. (International Standard Randomized Controlled Trial Number Register ISRCTN83772183 and clinicaltrials.gov Number NCT01038583).

Baseline Characteristics of Participants in the ASPREE (ASPirin in Reducing Events in the Elderly) Study

BACKGROUND

There are no primary prevention trials of aspirin with relevant geriatric outcomes in elderly people. ASPirin in Reducing Events in the Elderly (ASPREE) is a placebo-controlled trial of low-dose aspirin that will determine whether 5 years of daily 100-mg enteric-coated aspirin extends disability-free and dementia-free life in a healthy elderly population and whether these benefits outweigh the risks.

METHODS

Set in primary care, this randomized double-blind placebo-controlled trial has a composite primary endpoint of death, incident dementia or persistent physical disability. Participants aged 70+ years (non-minorities) or 65+ years (U.S. minorities) were free of cardiovascular disease, dementia, or physical disability and without a contraindication to, or indication for, aspirin. Baseline data include physical and lifestyle, personal and family medical history, hemoglobin, fasting glucose, creatinine, lipid panel, urinary albumin:creatinine ratio, cognition (3MS, HVLT-R, COWAT, SDMT), mood (CES-D-10), physical function (gait speed, grip strength), Katz activities of daily living and quality of life (SF-12).

RESULTS

Recruitment ended in December 2014 with 16,703 Australian and 2,411 U.S. participants, a median age of 74 (range 65-98) years and 56% women. Approximately 55% of the U.S. cohort were from minority groups; 9% of the total cohort. Proportions with hypertension, overweight, and chronic kidney disease were similar to age-matched populations from both countries although lower percentages had diabetes, dyslipidemia, and osteoarthritis.

DISCUSSION

Findings from ASPREE will be generalizable to a healthier older population in both countries and will assess whether the broad benefits of daily low-dose aspirin in prolonging independent life outweigh the risks.