A Preliminary Examination of the Concept of Frailty in the Elderly

Frailty has been defined as a state of increased vulnerability to adverse outcomes. The concept of frailty has been centered around counting the number of deficits in health, which can be diseases, disabilities, or symptoms. However, there is no consensus on how it should be quantified. Frailty has been considered synonymous with functional status and comorbidity, but these may be distinct concepts requiring different management. We compared two methods of defining a frailty phenotype, a count of deficits and a weighted score of health deficits incorporating the strength of association between each deficit and mortality. The strength of association was estimated using proportional hazards coefficients. The study uses data from the third National Health and Nutrition Examination Survey. We compared the two methodologies: frailty was associated with being older, Non-Hispanic Black, and having more comorbid chronic diseases. The predictive association of frail status with the incidence of death over 12 years was significant for the weighted phenotype, with hazard ratio 2.21, 95% confidence interval (CI) (2.03, 2.40). The unweighted predictive association of frail status with the incidence of death was also significant, with a lower hazard ratio of 1.96, 95% CI (1.79, 2.15). There was overlap and uniqueness in the definitions of frailty, functional status, and comorbidity that require further research. This study introduces a weighted score for defining a frailty phenotype that is more strongly predictive of mortality, and hence has potential to improve targeting and care of today's elderly.