A frailty index (FI) based on domain-level deficits identified by a comprehensive geriatric assessment (CGA) has been previously developed and validated in general geriatric patients. Our objectives were to construct an FI-CGA and to assess its construct validity in the context of geriatric oncology.
Five hundred and forty consecutive Japanese cancer patients who underwent CGA in a geriatric oncology department were included (median age 80 years, range 66 to 96 years). We have developed a 10-item fragility index based on deficits in 10 domains (FI-CGA-10): cognition, mood, communication, mobility, balance, nutrition, basic and instrumental activities of daily living, social support and comorbidity. Deficits in each area were rated 0 (no problem), 0.5 (minor problem) and 1.0 (major problem). Scores were calculated by dividing the sum of the scores for each domain by ten, then classified as fit ( 0.35). Construct validity was tested by correlating the FI-CGA-10 with other established measures of brittleness.
FI-CGA-10 has been well approximated by the gamma distribution. Overall, 20% of patients were in good shape, 41% were pre-frail and 39% were frail. FI-CGA-10 was correlated with the Canadian Study of Health and Aging (ESCS) Clinical Frailty Scale (r = 0.83), the definition of frailty based on the rules of the CVSA (r = 0.67) and the functional score of the ESCS (r = 0.77). Increasing levels of frailty were significantly associated with functional and cognitive impairments, a high co-morbidity burden, poor self-rated health, and low estimated survival probabilities.
The FI-CGA-10 is a user-friendly, construction-validated measure for quantifying the fragility of a CGA.
Implications for practice
We have constructed a user-friendly 10-item frailty index based on a comprehensive geriatric assessment (FI-CGA-10) for older people with cancer: cognition, mood, communication, mobility, balance, nutrition, basic and instrumental activities of daily life, social support and co-morbidity. The FI-CGA-10 was developed by simplifying the original FI-CGA used in the general geriatric setting while maintaining the validity of its content. We have demonstrated the construct validity of our index in a cohort of elderly people with various types of cancer. The advantage of the FI-CGA-10 is that a frailty score can be calculated more easily and interpreted in a more clinically sensitive manner than the original FI-CGA.