Assessing Global Frailty Scores: Development of a Global Burden of Disease-Frailty Index (GBD-FI)

Preserved Ratio Impaired Spirometry and COPD Accelerate Frailty Progression: Evidence From a Prospective Cohort Study

BACKGROUND

COPD has been found to be associated with frailty. However, longitudinal evidence for associations of COPD with frailty progression is inadequate. Furthermore, recent studies revealed a new phenotype of lung function impairment: preserved ratio impaired spirometry (PRISm) findings. Associations of PRISm findings and their transitions with frailty progression are unclear.

RESEARCH QUESTION

What are the associations of PRISm findings, transitions of PRISm findings, and COPD with frailty progression?

STUDY DESIGN AND METHODS

To analyze the associations of PRISm findings and COPD with frailty progression, 5,901 patients were included from the English Longitudinal Study of Ageing. Patients were classified into three lung function patterns of normal spirometry (NS) findings, PRISm findings, and COPD. Frailty progression was assessed by repeated measurements of the frailty index (FI) during follow-up. Among these 5,901 patients, 3,765 patients were included to analyze the associations of PRISm findings transitions with frailty progression. PRISm findings transitions were assessed based on the changes of lung function patterns after a 4-year interval. Linear mixed-effect models were used for statistical analyses.

RESULTS

The median follow-up periods were 9.5 years for the analyses of PRISm findings and COPD with frailty progression and 5.8 years for PRISm findings transitions with frailty progression. When compared with participants with NS findings, patients with PRISm findings and COPD demonstrated accelerated FI progression with additional annual increases of 0.301 (95% CI, 0.211-0.392; P < .001) and 0.172 (95% CI, 0.102-0.242; P < .001), respectively. Patients who transitioned from NS findings to PRISm findings also demonstrated accelerated FI progression when compared with those with stable NS findings (β = 0.242; 95% CI, 0.008-0.476; P = .042). However, no accelerated FI progression was found in patients with PRISm findings who transitioned to NS findings (β = 0.119; 95% CI, -0.181 to 0.418; P = .438).

INTERPRETATION

Our findings indicate that PRISm findings and COPD are associated with accelerated frailty progression. Further studies are needed to elucidate the causality of the association of PRISm findings and COPD with frailty.

Physiological aging and life-cycle labor supply across countries

We construct a cohort-based frailty index for 180 countries over the period 1990-2019. We use this measure of physiological aging to estimate the impact of deteriorating health on labor force participation. Our three-dimensional panel framework, in which the unit of observation is a cohort in a given country at a given age, allows us to control for a range of unobserved factors. Our identification strategy further exploits a compensating law of physiological aging to account for reverse causality. We find a negative effect of physiological aging on labor market participation: an increase of the frailty index by one percent leads to a reduction of labor force participation of about 0.6 (±0.2) percentage points. Since health deficits (in the frailty index) are accumulated at a rate of about 3 percent per year of life, almost all of the age-related decline in labor force participation can be motivated by deteriorating health.

Comparing frailty prevalence between countries: validation of the Global Burden of Disease study Frailty Index (GBD-FI) in the survey of health, ageing and retirement in Europe

BACKGROUND

Accurate comparable prevalence proportions are required to better understand the epidemiology of frailty. Estimates in many countries are missing or incomparable. The Global Burden of Disease Frailty Index (GBD-FI) applies the deficit accumulation model to generate frailty scores from items available in the Global Burden of Disease study.

OBJECTIVE

To externally validate the GBD-FI.

METHODS

Data were obtained from the Survey of Health Ageing and Retirement in Europe (SHARE). A 20-item modified GBD-FI was compared with established frailty measures: a 70-item frailty index (FI-70), the Clinical Frailty Scale (CFS), Frailty Phenotype (FP) and SHARE-FI. Area under receiver operating characteristic curves (AUC) were fitted to examine diagnostic accuracy for frailty and predictive validity for 2-year mortality.

RESULTS

In total, 31,624 participants aged ≥50 years from 15 countries were included. Frailty prevalence was 22% using the GBD-FI (ranging from 8% in Switzerland to 41% in Poland). The GBD-FI had good to excellent diagnostic accuracy for frailty, irrespective of approach; the AUC ranged from 0.86 (95% confidence interval: 0.85-0.87) measuring frailty using the CFS to 0.94 (0.93-0.94) with the FI-70. The GBD-FI had similar accuracy for 2-year mortality (AUC 0.71, 0.69-0.74) compared with the CFS (0.73; P = 0.186), FP (0.73; P = 0.392) and SHARE-FI (0.70; P = 0.255) but lower than the FI-70 (0.76; P < 0.001).

CONCLUSION

The GBD-FI demonstrated concurrent and predictive validity, suggesting it is a valid measure of frailty. It has the potential to be an efficient, replicable and consistent approach to comparing frailty between countries and regions across time using GBD data.

Physiological aging in India: The role of the epidemiological transition

We construct a cohort-based frailty index from age-related health deficits to investigate physiological aging in India over the period 1990-2019. During this period, the Indian states underwent at different speeds the epidemiological transition and experienced unprecedented economic growth. We show that the rate of physiological aging remained remarkably stable to the changing environment. Age-related health deficits increased by about 3 percent per year of age with little variation across states, ages, cohorts, and over time. We find that, with advancing epidemiological transition, health deficits for given age declined at the individual level (within states and within cohorts). Across cohorts born between 1900 and 1995, we show that, for given age, health deficits are higher for later-born cohorts until birth years around 1940 and remained trendless afterwards. We propose a selection-based theory of aging during the epidemiological transition that explains these facts.

Physiological aging around the World

We extract data on physiological aging by computing a frailty index for 201 countries over the period 1990–2019. Using panel estimation techniques, we show that the macro frailty index replicates basic regularities previously observed in related studies of aging at the individual level. We then use the frailty index to highlight trends of global physiological aging and its relationship to economic growth. Holding population age structure fixed, the global frailty index has on average increased by about 2 percent over the last 30 years. The average person has therefore aged by what corresponds to about one life-year of physiological aging. This overall trend is relatively similar across different geographical regions. We also document a negative relationship between physiological aging of the workforce and economic growth. According to our preferred specification, a one percent increase in the frailty index of the workforce is associated with a 1.5 percent decline of GDP per capita. This means that average annual growth of labor productivity would have been 0.1 percentage points higher without physiological aging in the period 1990-2019.

Comparison of two different frailty scales in the longitudinal Swedish Adoption/Twin Study of Aging (SATSA)

AIMS

Although up to 25% of older adults are frail, assessing frailty can be difficult, especially in registry data. This study evaluated the utility of a code-based frailty score in registry data by comparing it to a gold-standard frailty score to understand how frailty can be quantified in population data and perhaps better addressed in healthcare.

METHODS

We compared the Hospital Frailty Risk Score (HFRS), a frailty measure based on 109 ICD codes, to a modified version of the Frailty Index (FI) Frailty Index (FI), a self-report frailty measure, and their associations with all-cause mortality both cross-sectionally and longitudinally (follow-up = 36 years) in a Swedish cohort study (n = 1368).

RESULTS

The FI and HFRS were weakly correlated (rho = 0.11, p < 0.001). Twenty-two percent (n = 297) of participants were considered frail based on published cut-offs of either measure. Only 3% (n = 35) of participants were classified as frail by both measures; 4% (n = 60) of participants were considered frail by only the HFRS; and 15% (n = 202) of participants were considered frail based only on the FI. Frailty as measured by the HFRS showed greater variance and no clear increase or decrease with age, while frailty as measured by the FI increased steadily with age. In adjusted Cox proportional hazard models, baseline HFRS frailty (HR = 1.17, 95% CI 0.92, 1.49) was not statistically significantly associated with mortality, while FI frailty was (HR = 2.89, 95% CI 1.61, 2.23). These associations were modified by age and sex.

CONCLUSIONS

The HFRS may not capture the full spectrum of frailty among community-dwelling individuals, particularly at younger ages, in Swedish registry data.