The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within ...

The Microbiota-Gut-Brain Axis

Geriatricians have embraced the term "geriatric syndrome," using it extensively to highlight the unique features of common health conditions in older people. Geriatric syndromes, such as delirium, falls, incontinence, and frailty, are highly prevalent, multifactorial, and associated with substantial morbidity and poor outcomes. Nevertheless, this central geriatric concept has remained poorly defined. This article reviews criteria for defining geriatric syndromes and proposes a balanced approach of developing preliminary criteria based on peer-reviewed evidence. Based on a review of the literature, four shared risk factors-older age, baseline cognitive impairment, baseline functional impairment, and impaired mobility-were identified across five common geriatric syndromes (pressure ulcers, incontinence, falls, functional decline, and delirium). Understanding basic mechanisms involved in geriatric syndromes will be critical to advancing research and developing targeted therapeutic options, although given the complexity of these multifactorial conditions, attempts to define relevant mechanisms will need to incorporate more-complex models, including a focus on synergistic interactions between different risk factors. Finally, major barriers have been identified in translating research advances, such as preventive strategies of proven effectiveness for delirium and falls, into clinical practice and policy initiatives. National strategic initiatives are required to overcome barriers and to achieve clinical, research, and policy advances that will improve quality of life for older persons.

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Geriatric Syndromes: Clinical, Research, and Policy Implications of a Core Geriatric Concept

Geriatric syndromes : Clinical, research, and policy implications of a core geriatric concept. Commentary

Clinicians and researchers have shown increasing interest in frailty. Yet, there is still considerable uncertainty regarding the concept and its definition. In this article, we present perspectives on key issues and controversies discussed by scientists from 13 different countries, representing a diverse range of disciplines, at the 2006 Second International Working Meeting on Frailty and Aging. The following fundamental questions are discussed: What is the distinction, if any, between frailty and aging? What is its relationship with chronic disease? Is frailty a syndrome or a series of age-related impairments that predict adverse outcomes? What are the critical domains in its operational definition? Is frailty a useful concept? The implications of different models and approaches are examined. Although consensus has yet to be attained, work accomplished to date has opened exciting new horizons. The article concludes with suggested directions for future research.

Frailty: An Emerging Research and Clinical Paradigm—Issues and Controversies

Accumulating evidence implicates metabolites produced by gut microbes as crucial mediators of diet-induced host-microbial cross-talk. Here, we review emerging data suggesting that microbial tryptophan catabolites resulting from proteolysis are influencing host health. These metabolites are suggested to activate the immune system through binding to the aryl hydrocarbon receptor (AHR), enhance the intestinal epithelial barrier, stimulate gastrointestinal motility, as well as secretion of gut hormones, exert anti-inflammatory, anti-oxidative or toxic effects in systemic circulation, and putatively modulate gut microbial composition. Tryptophan catabolites thus affect various physiological processes and may contribute to intestinal and systemic homeostasis in health and disease.

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Microbial tryptophan catabolites in health and disease

OBJECTIVES: To identify factors associated with 1-year mortality in newly admitted and long-stay (in nursing home longer than 1 year) nursing home residents by linking Minimum Data Set (MDS) information with data from the National Death Index and use these factors to create a useful tool for estimating risk levels for 1-year mortality.

DESIGN: Retrospective cohort study with development and validation cohorts.

SETTING: All 643 Medicare and Medicaid certified nursing homes in New York State during the study period.

PARTICIPANTS: The study included data on residents collected during full MDS assessments from June 1994 through December 1997. A total of 100,669 nursing home residents met the inclusion criteria for the newly admitted resident analysis. The newly admitted development cohort included 60,341 residents, and the newly admitted validation cohort included 40,328 residents. A total of 36,125 nursing home residents met inclusion criteria for the long-stay (residing in nursing home>1 year) cohort. The long-stay development cohort included 22,749 residents, and the long-stay validation cohort included 15,068 residents.

MEASUREMENTS: The analytical approach was similar for the newly admitted and long-stay resident cohorts. Resident characteristics that were considered potential risk factors for mortality were examined individually in bivariate proportional hazards models, and factors with P < .05 were entered into a proportional hazards regression stepwise model. The strongest factors based on their chi-square values were selected for entry into a multivariate proportional hazards analysis. Hazard ratios (HRs), 95% confidence intervals, and P-values were derived from this model. A mortality risk index score was created for each resident by summing the value of each HR in the multivariate model for those who had the risk factor. A sensitivity analysis was performed to determine the effect of residents with an unknown death status. A similar analysis was performed on the validation cohort to validate the original results.

RESULTS: Major factors associated with 1-year mortality were identified in both the newly admitted and long-stay cohorts. In both newly admitted and long-stay residents, a higher mortality risk index score was associated with increased 1-year mortality in both the development and validation cohorts.

CONCLUSIONS: MDS data can identify major factors associated with 1-year mortality in newly admitted and long-stay nursing home residents. These factors can be used to stratify residents into risk categories for 1-year mortality. This information could be important to residents, their families, and their physicians when developing care plans, as well as to agencies interested in healthcare resource planning.

Mortality-related factors and 1-year survival in nursing home residents.

Multiple studies have identified conserved genetic pathways and small molecules associated with extension of lifespan in diverse organisms. However, extending lifespan does not result in concomitant extension in healthspan, defined as the proportion of time that an animal remains healthy and free of age-related infirmities. Rather, mutations that extend lifespan often reduce healthspan and increase frailty. The question arises as to whether factors or mechanisms exist that uncouple these processes and extend healthspan and reduce frailty independent of lifespan. We show that indoles from commensal microbiota extend healthspan of diverse organisms, including Caenorhabditis elegans, Drosophila melanogaster, and mice, but have a negligible effect on maximal lifespan. Effects of indoles on healthspan in worms and flies depend upon the aryl hydrocarbon receptor (AHR), a conserved detector of xenobiotic small molecules. In C. elegans, indole induces a gene expression profile in aged animals reminiscent of that seen in the young, but which is distinct from that associated with normal aging. Moreover, in older animals, indole induces genes associated with oogenesis and, accordingly, extends fecundity and reproductive span. Together, these data suggest that small molecules related to indole and derived from commensal microbiota act in diverse phyla via conserved molecular pathways to promote healthy aging. These data raise the possibility of developing therapeutics based on microbiota-derived indole or its derivatives to extend healthspan and reduce frailty in humans.

https://www.pnas.org/content/pnas/114/36/E7506.full.pdf

Indoles from commensal bacteria extend healthspan

The term “Geriatric Syndrome” is commonly used but ill defined. In publications, authors claim that all sorts of conditions are a “Geriatric Syndrome”, including, but not limited to, delirium,1 dementia,1 depression,2 dizziness,3 emesis,4 falls,1 gait disorders,1 hearing loss,1 insomnia,1 urinary incontinence,1 language disorders,1 functional dependence,5 lower extremity problems,6 oral and dental problems,6 malnutrition,1 osteoporosis,1 pain,1 pressure ulcers,1 silent angina pectoris,7 sexual dysfunction,6 syncope6 and vision loss.1 Can this be possible? Can any condition commonly encountered in older adults be a “Geriatric Syndrome”?

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What is a geriatric syndrome anyway

The protective effect of social engagement on 1-year mortality in a long-stay nursing home population.

BACKGROUND
Ineffective communication of hospital discharge instructions may have important implications for future health, function, and quality of life.

OBJECTIVE
To describe patient recall of predischarge communication of discharge instructions by hospital staff, and to demonstrate the feasibility a posthospitalization survey in this urban, public hospital population.

METHODS
Cross-sectional telephone survey of 269 patients age 70 years or older who were discharged from an academically affiliated urban public hospital between September 7, 2004, and January 19, 2005.

RESULTS
The mean length of stay of the respondents was 5.6 days (range, 0–56 days), and the mean number of admissions over the study period was 1.6 (range, 1–7 times). The respondents were interviewed a average of 3 days after discharge (range, 1–10 days). Only 43.7% of the respondents replied yes when asked, “Did anyone talk with you about how to care for yourself at home after this hospitalization?” Among those who recalled how they received care instructions (n = 103), approximately 66.0% (n = 68) reported receiving instructions “verbally,” 10.7% (n = 11) reported receiving written instructions, and 23.3% (n = 24) reported receiving both. More than half the respondents (54.2%) did not recall anyone talking with them about how to care for themselves after hospitalization. Other significant gaps in important patient information were identified.

CONCLUSIONS
We found that a posthospitalization survey was both feasible and revealing in this urban, public hospital population. Furthermore, interviewee recall of predischarge communication of discharge instructions by hospital staff demonstrated significant gaps in communication between these patients and the hospital care team at time of discharge. Journal of Hospital Medicine 2007;2:291–296. © 2007 Society of Hospital Medicine.

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Jonathan M. Flacker

Papers

Mortality-related factors and 1-year survival in nursing home residents.

Indoles from commensal bacteria extend healthspan

What is a geriatric syndrome anyway

The protective effect of social engagement on 1-year mortality in a long-stay nursing home population.

Hospital discharge information and older patients: Do they get what they need?