An Examination of the Concept of Frailty in the Elderly

• Other Authors: Griffin, Felicia R. (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Aging; Statistics; Epidemiology
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-9342

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 age, gender, ethnicity, and having 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 3.46, 95% confidence interval (CI) (2.78, 4.30) unadjusted and hazard ratio 1.89, 95% confidence interval (CI) (1.57, 2.30) adjusted. The unweighted predictive association of frail status with the incidence of death was also significant, with a lower hazard ratio of 3.13, 95% CI (2.53, 3.87) unadjusted and hazard ratio of 1.40 95% CI (1.20, 1.65) adjusted. When examining the association of frailty and cause specific death, frailty was associated with a higher risk of death due to CHD, Stroke, CVD, and Other causes for both male and female (unadjusted). However, after adjusting for various covariates death due to CHD, CVD, and Others causes remain significant for both males and females. When comparing the definition of osteoporosis or low bone mass to the model of frailty, femoral neck T-score declined significantly with increasing levels of frailty. There was overlap and uniqueness in the definitions of frailty, functional status, and comorbidity that require further research. Understanding the causal interrelationship could help explain why these three conditions are likely to co-occur. In addition, there is an association between frailty and dietary quality based on the Mediterranean diet. This study provides a more valuable understanding of the complex concept of frailty and the role latent variables in this concept. This study also 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. === A Dissertation submitted to the Department of Statistics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. === Spring Semester, 2015. === April 14, 2015. === Includes bibliographical references. === Daniel McGee, Professor Co-Directing Dissertation; Elizabeth Slate, Professor Co-Directing Dissertation; Myra Hurt, University Representative; Debajyoti Sinha, Committee Member.