Qian-Li Xue

Stimulus-response paradigm for characterizing the loss of resilience in homeostatic regulation associated with frailty

Frailty is a state of health signified by an increased vulnerability to adverse health outcomes in the face of stressors (e.g. infection). There is emerging consensus that research on both the theory and measurement of frailty must focus on the dynamic interactions within and across systems underlying the frailty syndrome. In this paper, we propose a dynamical systems modeling approach, based on the stimulus-response experimental paradigm, to propel future advances in the study of frailty. Our proposal is novel in that it provides a quantitative framework to operationalize and test the core notion underlying frailty that it signifies a loss of resilience in homeostatic regulation. The proposed framework offers many important benefits, including (a) insights into whether and how homeostatic regulation differs between frail and non-frail older adults, (b) identification of critical regulatory systems, if they exist, that could function as sentinel systems for screening and early detection of frailty, (c) establishment of the value of provocative tests that can provide maximal information on the integrity of systems identified in (b), and (d) evaluation and unification of diverse empirical descriptions of frailty by providing a mathematical framework anchored in quantifying the loss of resilience, an essential property of frailty.

CAPABLE trial: A randomized controlled trial of nurse, occupational therapist and handyman to reduce disability among older adults: Rationale and design

BACKGROUNDnAs the population ages, it is increasingly important to test new models of care that improve life quality and decrease health costs. This paper presents the rationale and design for a randomized clinical trial of a novel interdisciplinary program to reduce disability among low income older adults based on a previous pilot trial of the same design showing strong effect.nnnMETHODSnThe CAPABLE (Community Aging in Place, Advancing Better Living for Elders) trial is a randomized controlled trial in which low income older adults with self-care disability are assigned to one of two groups: an interdisciplinary team of a nurse, occupational therapist, and handyman to address both personal and environmental risk factors for disability based on participants functional goals, or an attention control of sedentary activities of choice. Both groups receive up to 10 home visits over 4 months.nnnOUTCOMESnThe primary outcome is decreased disability in self-care (ADL). Secondary outcomes are sustained decrease in self care disability as well as improvement in instrumental ADLS, strength, balance, walking speed, and health care utilization. Careful cost tracking and analysis using intervention data and claims data will enable direct measurement of the cost impact of the CAPABLE approach. CAPABLE has the potential to leverage current health care spending in Medicaid waivers, Accountable Care Organizations and other capitated systems to save the health care system costs as well as improving low income older adults ability to age at home with improved life quality.

Role of Late-Life Depression in the Association of Subclinical Cardiovascular Disease With All-Cause Mortality: Cardiovascular Health Study

Objectives: To evaluate whether late-life depression mediates the association of subclinical cardiovascular disease (CVD) with all-cause mortality. Method: Using data from 3,473 Cardiovascular Health Study participants, the Cox proportional hazards model was used to examine the direct and indirect (via late-life depression) effects of the association between baseline subclinical CVD and all-cause mortality with weights derived from multivariable logistic regression of late-life depression on subclinical CVD. Results: Subclinical CVD led to a higher risk of all-cause mortality (hazard ratio [HR] = 1.51, 95% confidence interval, [CI] = [1.42, 1.94]). Total effect of subclinical CVD on all-cause mortality was decomposed into direct (HR = 1.41, 95% CI = [1.37, 1.58]) and indirect (HR = 1.07, 95% CI = [1.01, 1.23]) effects; 16.3% of the total effect of subclinical CVD on all-cause mortality was mediated by late-life depression. Discussion: Late-life depression accounts for little, if any, of the association between subclinical CVD, a risk factor of all-cause mortality, and all-cause mortality.

PERSISTENT DEPRESSIVE SYMPTOMS AS PARTIAL MEDIATORS IN THE ASSOCIATIONS BETWEEN SUBCLINICAL CARDIOVASCULAR DISEASE WITH ONSET OF MILD COGNITIVE IMPAIRMENT AND DEMENTIA

R03BA01-R03BA09, H02AB01-H02AB17). Only valid dementia diagnoses were considered; a diagnosis was found to be valid if a patient received a confirmative dementia diagnosis in the period from 2006-2013. The use of glucocorticoids (GCC) was defined by receiving at least one treatment during the observation period. We controlled for sex, age, major comorbidities at old age, beta2adrenergic agonists (ATC: R03AC02-R03AC19), and took interactions between asthmatics and GCC users into account. Results:During the observation period, 110,268 persons received at least one GCC treatment Out of 227,008 dementia-free persons, 23,075 persons developed dementia until the end of 2013. The hazard of suffering from dementia was significantly lower for GCC users compared to non-users (HR1⁄40.87; 95% CI1⁄40.85-0.90). Asthmatics were also at a slightly lower risk of having dementia in contrast to non-Asthmatics (HR1⁄40.95; 95% CI1⁄40.90-0.99). When interactions with asthma were taken into account, users of GCC among non-asthmatics showed a reduced risk of developing dementia (HR1⁄40.84; 95% CI1⁄40.82-0.87) as well as among asthmatics (GCC: HR1⁄40.79; 95% CI1⁄40.74-0.83 vs. no GCC: HR1⁄40.91; 95% CI1⁄40.84-0.99). Conclusions:Longitudinal German health claims data indicate that the use of GGCs may reduce subsequent risk of suffering from dementia. However, these results should be verified in clinical trials.