What is the most commonly used frailty scoring system in research, particularly for older adults with cognitive impairment due to dementia?

Most Utilized Frailty Scoring System in Research

The two most commonly used frailty assessment approaches in research are the Frailty Phenotype (Fried Model) and the Frailty Index based on deficit accumulation, with these two approaches having predominated since their introduction in 2001. 1

The Two Predominant Approaches

Frailty Phenotype (Fried Model)

• This approach conceptualizes frailty as a physical syndrome defined by five specific criteria: low grip strength, slow walking speed, unintentional weight loss, reduced usual activities, and self-reported exhaustion 1
• Frailty is diagnosed when three or more of these five features are present, creating a six-point scale based on the number of attributes present 1
• The original phenotype is sometimes referred to as "physical frailty" to distinguish it from variants like cognitive frailty, social frailty, and organ-specific frailties 1

Frailty Index (Deficit Accumulation Model)

• This approach views frailty as a general age-related state of poor health proportional to accumulated health deficits rather than a specific syndrome 1
• The degree of frailty is expressed as the fraction of deficits present relative to the total number considered (typically at least 30 age-related items) 1
• Deficits can be drawn from symptoms, signs, laboratory values, or other measures, with the specific items varying by context 1

Operational Variations and Clinical Tools

Common Clinical Adaptations

• The FRAIL Scale is a popular self-report variant that adds comorbidity assessment to the phenotype approach 1, 2
• The Clinical Frailty Scale (CFS) proposes ordered combinations of high-information deficits to grade frailty severity on a 1-9 scale 1, 2
• The CFS has become widely used across multiple settings, with 62% of studies using it published after 2015 and 63% conducted in hospitalized patients 3
• In critical care, the CFS is the most commonly used scale, involving assessment of approximately 40% of patients over 75 years 4

Important Caveats About Shorter Versions

• Modified frailty indices using fewer items (such as 11-item versions common in surgical literature) have been criticized as too brief to constitute true deficit accumulation indices 1
• When at least 30 age-related items are considered in a frailty index, the degree of frailty does not depend strongly on which specific items are counted 1

Comparative Performance

Similarities Between Approaches

• Both the phenotype and deficit accumulation approaches consistently classify people at increased risk of death at the group level 1
• They reduce the explanatory power of age alone and appear to share genetic determinants 1
• Each captures that not all people age at the same rates and that individuals of the same age have different mortality risks 1

Context-Specific Considerations for Dementia Populations

• For older adults with cognitive impairment due to dementia, expert consensus recommends using brief, straightforward tools accessible to various clinicians 1
• The CFS demonstrates strong associations with both short and long-term mortality, as well as functional outcomes in older adults 4
• However, the CFS shows reduced correlation in patients with severe dementia (r = 0.442 compared to r = 0.706 in general populations), making it less suitable for this specific subgroup 5

Research Utilization Patterns

• The operationalization of each approach varies considerably across studies, but results remain robust despite these variations 1
• Sometimes only four of the five phenotype items are used when databases lack complete data 1
• Self-reported data or different questions than originally proposed are frequently employed in research settings 1
• The CFS has been examined in association with outcomes 526 times across studies, proving predictive in 74% of cases, with particularly strong prediction of mortality (87% of the time) 3