Functional outcomes following knee replacement in community-dwelling older adults.

BACKGROUND: Knee replacements are increasingly performed in older adults but uncertainty remains regarding their benefits in the context of age-related decline in physical function and other comorbidities. This study aimed to examine (1) the effect of knee replacement on functional outcomes in the context of age-related decline in physical function and (2) the factors associated with minimal important improvement in physical function after knee replacement in community-dwelling older adults aged ≥ 70 years. METHODS: This cohort study was performed within the ASPREE trial, with 889 participants undergoing knee replacement during the trial and 858 age- and sex-matched controls without knee or hip replacement identified from 16,703 Australian participants aged ≥ 70 years. Health-related quality of life was assessed annually using the SF-12, including its physical and mental component summary (PCS and MCS). Gait speed was measured biennially. Multiple linear regression and analysis of covariance were used to adjust for potential confounders. RESULTS: Participants with knee replacement had significantly lower pre- and post-replacement PCS scores and gait speed compared with age- and sex-matched controls. Participants with knee replacement had significant improvement in PCS score following knee replacement (mean change 3.6, 95% CI 2.9-4.3) while PCS score remaining unchanged in age- and sex-matched controls (-0.02, 95% CI -0.6 to 0.6) during follow-up period. The greatest improvements were observed for bodily pain and physical function. Following knee replacement, 53% of participants experienced minimal important improvement in PCS score (increased by ≥ 2.7), while 24% experienced worsened PCS score (reduced by > 2.7). Participants experiencing improved PCS score postoperatively had significantly lower PCS and higher MCS scores pre-surgery. CONCLUSIONS: Although community-based older adults experienced a significant improvement in PCS scores after knee replacement, their postoperative physical functional status remained significantly lower than age- and sex-matched controls. The degree of preoperative physical function impairment was a strong predictor of functional improvement, suggesting that this could be an important consideration when identifying older people most likely to benefit from knee replacement surgery.

The Association between Frailty and Dementia-Free and Physical Disability-Free Survival in Community-Dwelling Older Adults.

INTRODUCTION: Frailty is a common geriatric syndrome that adversely impacts health outcomes. This study examined correlates of physical frailty in healthy community-dwelling older adults and studied the effect of frailty on disability-free survival (DFS), defined as survival free of independence-limiting physical disability or dementia. METHODS: This is a post hoc analysis of 19,114 community-dwelling older adults (median age: 74.0 years, interquartile range or IQR: 6.1 years) from Australia and the USA enrolled in the "ASPirin in Reducing Events in the Elderly (ASPREE)" clinical trial. Frailty was assessed using a modified Fried phenotype and a deficit accumulation frailty index (FI) utilizing a ratio score derived from 66 items. Multinomial logistic regression was used to examine the correlates of frailty and Cox regression to analyze the association between frailty and DFS (and its components). RESULTS: At study enrollment, 39.0% were prefrail, and 2.2% of participants were frail, according to Fried phenotype. Older age, higher waist circumference, lower education, ethnoracial origin, current smoking, depression, and polypharmacy were associated with prefrailty and frailty according to Fried phenotype and FI. Fried phenotype defined prefrailty and frailty predicted reduced DFS (prefrail: HR: 1.67; 95% CI: 1.50-1.86 and frail: HR: 2.80; 95% CI: 2.27-3.46), affecting each component of DFS including dementia, physical disability, and mortality. Effect sizes were larger, according to FI. CONCLUSION: Our study showed that prefrailty is common in community-dwelling older adults initially free of cardiovascular disease, dementia, or independence-limiting physical disability. Prefrailty and frailty significantly reduced disability-free survival. Addressing modifiable correlates, like depression and polypharmacy, might reduce the adverse impact of frailty on dementia-free and physical disability-free survival.

Functional Outcomes Following Hip Replacement in Community-Dwelling Older Adults.

Uncertainty remains regarding the benefit of hip replacement in older adults in the context of age-related decline in physical function. This study aimed to examine the effect of hip replacement on functional outcomes and identify factors associated with clinically important improvement in physical function postoperatively in community-dwelling older adults. This cohort study was performed within the ASPREE trial, with 698 participants receiving hip replacement and 677 age- and sex-matched controls without knee or hip replacement during the trial drawn from 16,703 Australian participants aged ≥70 years. Health status (physical and mental component summary [PCS and MCS]) was assessed annually using the SF-12. Participants receiving hip replacement had significantly lower pre- and post-replacement PCS scores compared with controls (p < 0.0001). There was significant improvement in PCS score following hip replacement (mean change 4.9, 95%CI 4.0−5.7) but no change in controls (0.01, 95%CI −0.7−0.7). Following hip replacement, 46.7% of participants experienced clinically important improvement in PCS score, while 15.5% experienced worsened PCS score. Participants experiencing improved postoperative PCS score had significantly lower PCS and higher MCS scores preoperatively. The degree of preoperative physical function impairment was a significant indicator of older people most likely to benefit from hip replacement surgery.

Similar mortality risk in incident cognitive impairment and dementia: Evidence from the ASPirin in Reducing Events in the Elderly (ASPREE) trial.

BACKGROUND: This study examined the risk of mortality in older adults with newly detected cognitive impairment or dementia. METHODS: Data from the Australian cohort of the ASPirin in Reducing Events in the Elderly (ASPREE) trial were examined. The ASPREE clinical trial compared daily low-dose aspirin to a placebo and involved 16,703 individuals aged 70 years and over, who were without major cognitive impairment, physical disability, or cardiovascular disease at recruitment. During the trial, evidence of cognitive impairment, based on cognitive testing and medical record information, triggered dementia adjudication of participants using DSM-IV criteria. Cox proportional hazard models were used to compare mortality rates across the dementia, trigger-only, and no-trigger groups. RESULTS: Over a median 4.7-year follow-up period, 806 participants triggered dementia adjudication, with 485 (60.2%) judged to have dementia. Following recruitment, mortality risks were 32.9, 33.6, and 10.8 events per 1000 person-years in the dementia, trigger-no-dementia, and no-trigger groups, respectively. In the fully adjusted model, mortality risks remained higher in the dementia and trigger-no-dementia groups, with hazard ratios of 1.7 (95% CI: 1.3-2.1) and 1.9 (95% CI: 1.5-2.6), respectively. There was no discernible difference between the dementia and trigger-no-dementia groups in mortality rates following recruitment, or following a dementia trigger. These two groups were more likely to die from sepsis, respiratory disease, and dementia, but less likely to die from cancer than the no-trigger group, χ2  = 161.5, p < 0.001. CONCLUSION: ASPREE participants who triggered for a dementia evaluation experienced a substantially higher mortality rate than those who remained cognitively intact. The increase was indistinguishable among persons who met DSM-IV criteria for dementia vs. those who triggered for a dementia evaluation but failed to meet DSM-IV criteria. Future work should investigate whether earlier detection of cognitive decline can be used to identify and prevent early mortality.

Effect of Aspirin on Activities of Daily Living Disability in Community-Dwelling Older Adults.

BACKGROUND: Cerebrovascular events, dementia, and cancer can contribute to physical disability with activities of daily living (ADL). It is unclear whether low-dose aspirin reduces this burden in aging populations. In a secondary analysis, we now examine aspirin's effects on incident and persistent ADL disability within a primary prevention aspirin trial in community-dwelling older adults. METHODS: The ASPREE (ASPirin in Reducing Events in the Elderly) trial of daily 100 mg aspirin versus placebo recruited 19 114 healthy adults aged 70+ years (65+ years if U.S. minority) in Australia and the United States. Six basic ADLs were assessed every 6 months. Incident ADL disability was defined as inability or severe difficulty with ≥1 ADL; persistence was confirmed if the same ADL disability remained after 6 months. Proportional hazards modeling compared time to incident or persistent ADL disability for aspirin versus placebo; death without prior disability was a competing risk. RESULTS: Over a median of 4.7 years, incident ADL disability was similar in those receiving aspirin (776/9525) and placebo (787/9589) with walking, bathing, dressing, and transferring the most commonly reported. Only 24% of incident ADL disability progressed to persistent. Persistent ADL disability was lower in the aspirin group (4.3 vs 5.3 events/1000 py; hazard ratio [HR] = 0.81, 95% confidence interval [CI]: 0.66-1.00), with bathing and dressing the most common ADL disabilities in both groups. Following persistent ADL disability, there were more deaths in the aspirin group (24 vs 12). DISCUSSION: Low-dose aspirin in initially healthy older people did not reduce the risk of incident ADL disability, although there was evidence of reduced persistent ADL disability.

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 .).

Community-Based Intervention to Improve Cardiometabolic Targets in Patients With Stroke: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Many guidelines for secondary prevention of stroke focus on controlling cardiometabolic risk factors. We investigated the effectiveness of a management program for attaining cardiometabolic targets in survivors of stroke/transient ischemic attack. METHODS: Randomized controlled trial of survivors of stroke/transient ischemic attack aged ≥18 years. General practices were randomized to usual care (control) or an intervention comprising specialist review of care plans and nurse education in addition to usual care. The outcome is attainment of pre-defined cardiometabolic targets based on Australian guidelines. Multivariable regression was undertaken to determine efficacy and identify factors associated with attaining targets. RESULTS: Overall, 283 subjects were randomized to the intervention and 280 to controls. Although we found no between-group difference in overall cardiometabolic targets achieved at 12 months, the intervention group more often achieved control of low-density lipoprotein cholesterol (odds ratio, 1.97; 95% confidence interval, 1.18-3.29) than controls. At 24 months, no between-group differences were observed. Medication adherence was ≥80% at follow-up, but uptake of lifestyle/behavioral habits was poor. Older age, being male, being married/living with partner, and having greater functional ability or a history of diabetes mellitus were associated with attaining targets. CONCLUSIONS: The intervention in this largely negative trial only had a detectable effect on attaining target for lipids but not for other factors at 12 months or any factor at 24 months. This limited effect may be attributable to inadequate uptake of behavioral/lifestyle interventions, highlighting the need for new or better approaches to achieve meaningful behavioral change. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: ACTRN12608000166370.

Effectiveness of an Intervention to Improve Risk Factor Knowledge in Patients With Stroke: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Despite the benefit of risk awareness in secondary prevention, survivors of stroke are often unaware of their risk factors. We determined whether a nurse-led intervention improved knowledge of risk factors in people with stroke or transient ischemic attack. METHODS: Prospective study nested within a randomized controlled trial of risk factor management in survivors of stroke or transient ischemic attack. INTERVENTION: 3 nurse education visits and specialist review of care plans. OUTCOME: unprompted knowledge of risk factors of stroke or transient ischemic attack at 24 months. Effect of intervention on knowledge and factors associated with knowledge were determined using multivariable regression models. RESULTS: Knowledge was assessed in 268 consecutive participants from the main trial, 128 in usual care and 140 in the intervention. Overall, 34% of participants were unable to name any risk factor. In adjusted analyses, the intervention group had better overall knowledge than controls (incidence risk ratio, 1.26; 95% confidence interval, 1.00-1.58). Greater functional ability and polypharmacy were associated with better knowledge and older age and having more comorbidities associated with poorer knowledge. CONCLUSIONS: Overall knowledge of risk factors of stroke or transient ischemic attack was better in the intervention group than controls. However, knowledge was generally poor. New and more effective strategies are required, especially in subgroups identified as having poor knowledge. CLINICAL TRIAL REGISTRATION: URL: http://www.anzctr.org.au. Unique identifier: ACTRN12608000166370.

Platelet-derived growth factor B retention is essential for development of normal structure and function of conduit vessels and capillaries.

OBJECTIVE: Extracellular retention of PDGF-B has been proposed to play an important role in PDGF-B signalling. We used the PDGF-B retention motif knockout mouse (RetKO) to study the effects of retention motif deletion on development of micro- and macrovascular structure and function. METHODS: Passive and active properties of conduit vessels were studied using myograph techniques and histological examination. Capillary structure and function was studied using measurements of capillary density in skeletal muscle and by assessing aerobic physical performance in a treadmill setup. Cardiac function was assessed using echocardiography. RESULTS: Myograph experiments revealed an increased diameter and stiffness of the aorta in RetKO. Histological examination showed increased media collagen content and a decreased number of aortic wall layers, however with a similar number of vascular smooth muscle cells. This outward eutrophic remodelling of the aorta was accompanied by endothelial dysfunction. RetKO showed decreased capillary density in skeletal muscle and signs of a defective delivery of capillary oxygen to skeletal muscle, as shown by a decreased physical performance. In RetKO mice, echocardiography revealed an adaptive eccentric cardiac hypertrophy. CONCLUSION: We conclude that retention of PDGF-B during development is essential for a normal conduit vessel function in the adult mouse. Furthermore, PDGF-B retention is also necessary for the development of an adequate capillary density, and thereby for a normal oxygen delivery to skeletal muscle. The lack of primary effects on cardiac function supports the redundant role of PDGF-B in cardiac development.

Bovine growth hormone transgenic mice are resistant to diet-induced obesity but develop hyperphagia, dyslipidemia, and diabetes on a high-fat diet.

It is known that bovine GH (bGH) transgenic mice have increased body mass, insulin resistance, and altered lipoprotein metabolism when fed a normal diet (ND). In this study, the effects of 8 wk of high-fat diet (HFD) were investigated in 6-month-old male bGH mice. Although littermate controls had unchanged energy intake, energy intake was higher in the bGH mice on a HFD than on a low-fat diet. Nevertheless, the bGH mice were resistant to diet-induced weight gain, and only in the bGH mice did the HFD result in increased energy expenditure. Glucose oxidation was higher in the bGH mice compared with littermate controls on both a HFD and ND. In addition, the bGH mice had 0.5 C higher body temperature throughout the day and increased hepatic uncoupling protein 2 expression; changes that were unaffected by the HFD. On a HFD, the effect of bGH overexpression on serum triglycerides and apolipoprotein B was opposite to that on a ND, resulting in higher serum concentrations of triglycerides and apolipoprotein B compared with littermate controls. Increased serum triglycerides were explained by decreased triglyceride clearance. The HFD led to diabetes only in the bGH mice. In conclusion, bGH transgenic mice were resistant to diet-induced obesity despite hyperphagia, possibly due to increased energy expenditure. On a HFD, bGH mice became dyslipidemic and diabetic and thereby more accurately reflect the metabolic situation in acromegalic patients.

Reduced exercise endurance in interleukin-6-deficient mice.

IL-6 is produced and released in large amounts from skeletal muscle during prolonged exercise in both mice and humans, but there are few data indicating the biological significance of this. IL-6 exerts metabolic effects such as stimulating energy expenditure and reducing body fat mass. We have now investigated the effects of IL-6 deficiency on exercise endurance and energy expenditure in preobese and obese IL-6-deficient (IL-6(-/-)) mice. Four-month-old preobese and 7-month-old obese IL-6(-/-) male mice backcrossed to C57BL/6 and their littermate controls were exercised on a treadmill, and energy expenditure was measured as oxygen consumption with the use of indirect calorimetry. The preobese IL-6(-/-) mice were significantly leaner than the control mice, whereas the older IL-6(-/-) mice, as expected, had developed obesity. Resting young, but not older, IL-6(-/-) mice had an elevated respiratory exchange ratio (RER), indicating that they oxidize carbohydrates rather than fat for energy utilization. During exercise, the young and older IL-6(-/-) mice had a reduced endurance and a progressive decrease in oxygen consumption compared with control mice. There was no difference in RER in young IL-6(-/-) mice, whereas RER was enhanced in older IL-6(-/-), mice during exercise. In summary, IL-6(-/-) mice have reduced endurance and energy expenditure during exercise, suggesting that IL-6 is necessary for normal exercise capacity.