Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Protein Networks

Protein Networks

An organism can have thousands of different proteins, and these proteins must cooperate to ensure the health of an organism. Proteins bind to other proteins and form complexes to carry out their functions. Many proteins interact with multiple other proteins creating a complex network of protein interactions.
These interactions can be represented through maps depicting protein-protein interaction networks, represented as nodes and edges. Nodes are circles that are representative of a protein,...

Internal Energy

Internal Energy

The total of all possible kinds of energy present in a substance is called the internal energy (U), sometimes symbolized as E. Suppose a system with initial internal energy, Uinitial, undergoes a change in energy (transfer of work or heat), and the final internal energy of the system is Ufinal. Change in internal energy equals the difference between Ufinal and Uinitial.

Internal Energy

Internal Energy

The internal energy of a thermodynamic system is the sum of the kinetic and potential energies of all the molecules or entities in the system. The kinetic energy of an individual molecule includes contributions due to its rotation and vibration, as well as its translational energy. The potential energy is associated only with the interactions between one molecule and the other molecules of the system. Neither the system's location nor its motion is of any consequence as far as the internal...

Internal Receptors

Internal Receptors

Many cellular signals are hydrophilic and therefore cannot pass through the plasma membrane. However, small or hydrophobic signaling molecules can cross the hydrophobic core of the plasma membrane and bind to internal, or intracellular, receptors that reside within the cell. Many mammalian steroid hormones use this mechanism of cell signaling, as does nitric oxide (NO) gas.

Network Covalent Solids

Network Covalent Solids

Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...

International System of Units

International System of Units

The International System of Units, known as the SI system, is a universally accepted measurement system recognized and used worldwide. The SI system is based on a set of three base units considered absolute, and their values do not change with location. These base units are meters, kilograms, and seconds.
Prefixes are used to define both larger and smaller quantities in the SI system. For example, milli, micro, and nano define smaller quantities, while kilo, mega, and giga are used to define...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Statins and survival free of incident frailty among older US veterans.

European heart journal·2026

Same author

Adaptive balancing of effort, accuracy and response speed in anomia treatment for post-stroke aphasia in community-based settings in the USA: a within-subjects randomised controlled trial protocol.

BMJ open·2026

Same author

Inside Semantic Feature Analysis: A Within-Trial Analysis of Feature Quantity and Quality.

American journal of speech-language pathology·2026

Same author

Assessing the Cost Effectiveness of an Incremental Lipid-Lowering Therapy Approach After Coronary Artery Bypass Grafting Using Nationwide Data.

Journal of the American Heart Association·2026

Same author

Always Look at the Feet: The Long Toenail Sign in an Outpatient Geriatrics Clinic.

Journal of the American Geriatrics Society·2026

Same author

Frailty.

Annals of internal medicine·2026

Search research articles

Related Experiment Video

Updated: Feb 7, 2026

Frailty Assessment in an Aging Mouse Model

Frailty Assessment in an Aging Mouse Model

Published on: September 23, 2025

Evaluating Frailty Index Integrity: Insights from an International Network Study.

Robert Cavanaugh^1,2, Chelsea Wong^3,4, Louisa H Smith^2,3

¹MGH Institute of Health Professions, Boston, MA.

Medrxiv : the Preprint Server for Health Sciences

|February 6, 2026

Summary

Deficit-accumulation Frailty Indices (FIs) show varying results across countries. Frailty Indices (FIs) developed in one context may not be externally valid when applied in another due to differences in data and coding practices.

More Related Videos

Measuring Frailty in HIV-infected Individuals. Identification of Frail Patients is the First Step to Amelioration and Reversal of Frailty

Measuring Frailty in HIV-infected Individuals. Identification of Frail Patients is the First Step to Amelioration and Reversal of Frailty

Published on: July 24, 2013

Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Published on: July 26, 2024

Related Experiment Videos

Last Updated: Feb 7, 2026

Frailty Assessment in an Aging Mouse Model

Frailty Assessment in an Aging Mouse Model

Published on: September 23, 2025

Measuring Frailty in HIV-infected Individuals. Identification of Frail Patients is the First Step to Amelioration and Reversal of Frailty

Measuring Frailty in HIV-infected Individuals. Identification of Frail Patients is the First Step to Amelioration and Reversal of Frailty

Published on: July 24, 2013

Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Author Spotlight: Assessing Surgical Frailty with Point-of-Care Ultrasound of Quadriceps Muscles

Published on: July 26, 2024

Area of Science:

Gerontology
Health Informatics
Epidemiology

Background:

Deficit-accumulation Frailty Indices (FIs) are widely used to assess physiological reserve in aging populations.
Common Data Models (CDMs) facilitate international application of FIs, but their validity across different healthcare systems is uncertain.

Purpose of the Study:

To compare the validity and estimates of two electronic health record (EHR)-based Frailty Indices (FIs): the US-based Veterans Affairs FI (VAFI) and the UK-based electronic FI (eFI).
To assess the external validity of FIs when applied across different international databases and healthcare contexts.

Main Methods:

An international network study compared VAFI and eFI estimates across five large EHR databases in the US and UK.
Data included the *All of Us* and IQVIA Pharmetrics+ databases (US), and IMRD-THIN, IMRD-EMIS, and UK BioBank databases (UK).
Analyses included variations in lookback periods and FI construction.

Main Results:

Significant discrepancies in frailty prevalence were observed between VAFI and eFI across US and UK databases.
In US databases, VAFI identified higher frailty proportions (e.g., 10.3% vs. 2.5% in *All of Us*).
In UK databases, eFI identified higher frailty proportions (e.g., 0.08% vs. <0.003% in IMRD-THIN).

Conclusions:

Frailty Index (FI) estimates are context-dependent, influenced by local coding behaviors and healthcare system incentives.
The external validity of FIs is limited, even when using Common Data Models (CDMs).
Caution is advised when applying FIs outside their original development context; further instrument development is recommended.