In the last Work Package 2 update we reported that the vaccination study had been completed. One of the goals of the vaccination study is to research if frailty parameters may be predictive of vaccination response. In this update we provide analysis of the data.

There are major differences in how individuals and their immune systems respond to ageing. Some individuals have difficulty with daily tasks such as climbing stairs and reading the fine print in the newspaper from around the age of 60, whereas some 79-year-old people are not only on their feet every day but may even work as the President of the United States. The frailty phenotype is used to describe elderly people with declining health that leads to physical impairment, disease and is strongly associated with mortality. The golden standard for measuring a person’s frailty is the frailty index as described by Rockwood and Mitnitski1, which is known to be a better predictor of hospitalization and mortality than age itself1–3.

To calculate the frailty index, 30-40 so-called “deficits” are scored between 0 (not present) and 1 (present) per person. The average of these scores gives the frailty index, which is also between 0 (not frail) and 1 (most frail). However, the authors stated that a frailty score higher than 0.67 is not compatible with life. The deficits can range from disorders or diseases to measured parameters or the self-scores of participants. Deficits must meet certain criteria, for example, a deficit must be associated with health; the frequency must increase with age; and the deficit must be present in ≥1% of the study population but not in >80% under age 80. In addition, all the deficits together must cover a range of health systems1,4.

In the VITAL cohort, we were able to identify and score 31 appropriate deficits for 319 participants at the T0 visit (pre-vaccination). For some examples, see Table 1, we found that the frailty index generally increases with age (as expected) but also shows large differences between participants (Figure 1).

We have since confirmed that our frailty index meets the characteristics and conditions as stated in the literature1–3. Our next steps are to investigate whether frailty can have a predictive value for vaccination success, and to link frailty to changes in serum markers and cellular phenotypes.

Deficit Question from VITAL Database Scoring  
Stroke –          Have you ever had a stroke? “yes”

“no”

 1

0
Caregiver –          Do you receive informal care from a caregiver?

–          Do you receive care/treatment from a home care worker?

–          Do you receive care/treatment from a district nurse?

 “yes” to any

“no” to all

 1

0
Seeing –          Are your eyes good enough to be able to read the small letters in the newspaper (with glasses or contact lenses if necessary)? “No, I cannot”

“Yes, with a lot of effort”

“Yes, with a little effort”

“Yes, without effort”

 1

0,66

0,33

0
Diabetes –          Have you been diagnosed with diabetes? “yes”

“no”

 1

0
Medication usage –          Have you used prescription medication in the 3 months prior to the study? and/or Have you used prescription medication during the study? Participant uses ≥5 medications

Participant uses <5 medications

 1

0

Sources:

  1. Searle SD, Mitnitski A, Gahbauer EA, Gill TM, Rockwood K. A standard procedure for creating a frailty index. BMC Geriatr. 2008;8(1):1-10. doi:10.1186/1471-2318-8-24/TABLES/3
  2. Mitnitski AB, Mogilner AJ, Rockwood K. Accumulation of deficits as a proxy measure of aging. ScientificWorldJournal. 2001;1:323-336. doi:10.1100/tsw.2001.58
  3. Rockwood K, Song X, Mitnitski A. Changes in relative fitness and frailty across the adult lifespan: evidence from the Canadian National Population Health Survey. CMAJ. 2011;183(8). doi:10.1503/CMAJ.101271
  4. Rockwood K, Blodgett JM, Theou O, et al. A Frailty Index Based On Deficit Accumulation Quantifies Mortality Risk in Humans and in Mice. Sci Reports 2017 71. 2017;7(1):1-10. doi:10.1038/srep43068