Objectives: Most conceptual and operational definitions of frailty place heavy emphasis on the physical problems encountered by older people. The accompanying models are based largely on a medical model. An integral approach is almost never adopted. This study aims to develop both an integral operational definition of frailty and an integral conceptual model of frailty.
Design: In order to achieve these aims, a thorough literature search was performed on components of operational definitions and models of frailty. In addition, experts (N=17) were consulted during two expert meetings.
Results: There was consensus among the experts on the inclusion of the following components in the operational definition of frailty: strength, balance, nutrition, endurance, mobility, physical activity and cognition. Some respondents indicated that they would wish to add components from the psychological or social domain. Supported by results from the literature search, a new integral operational definition of frailty was developed. This operational definition lies at the heart of an integral conceptual working model of frailty. This model expresses the relationships between three domains of frailty, adverse outcomes such as disability and the determinants.
Conclusion: The model should be able to serve as a basis for further scientific research on frailty. The model also provides a framework for the development of a measurement instrument which can be used for the identification of frail elderly persons.