Abstract
Background Physical activity is assumed to be important in the prevention and treatment of frailty. It is unclear, however, to what extent frailty can be influenced because instruments designed to assess frailty have not been validated as evaluative outcome instruments in clinical practice.
Objectives The aims of this study were: (1) to develop a frailty index (ie, the Evaluative Frailty Index for Physical Activity [EFIP]) based on the method of deficit accumulation and (2) to test the clinimetric properties of the EFIP.
Design The content of the EFIP was determined using a written Delphi procedure. Intrarater reliability, interrater reliability, and construct validity were determined in an observational study (n=24).
Method Intrarater reliability and interrater reliability were calculated using Cohen kappa and intraclass correlation coefficients (ICCs). Construct validity was determined by correlating the score on the EFIP with those on the Timed “Up & Go” Test (TUG), the Performance-Oriented Mobility Assessment (POMA), and the Cumulative Illness Rating Scale for Geriatrics (CIRS-G).
Results Fifty items were included in the EFIP. Interrater reliability (Cohen kappa=0.72, ICC=.96) and intrarater reliability (Cohen kappa=0.77 and 0.80, ICC=.93 and .98) were good. As expected, a fair to moderate correlation with the TUG, POMA, and CIRS-G was found (.61, −.70, and .66, respectively).
Limitations Reliability and validity of the EFIP have been tested in a small sample. These and other clinimetric properties, such as responsiveness, will be assessed or reassessed in a larger study population.
Conclusion The EFIP is a reliable and valid instrument to evaluate the effect of physical activity on frailty in research and in clinical practice.
Footnotes
Ms de Vries was responsible for study design and management, data collection, statistical analysis, and preparation of the manuscript. Dr Staal and Dr Nijhuis-van der Sanden were responsible for study design and statistical analysis. All authors contributed to interpretation of the study data and drafting the article, and all approved the final version of the manuscript. The authors thank Elly van Selst, Nina Kremer, and Miriam Kleine for their help with the data collection.
This study was part of the Designing Optimal Interventions for Physical Therapy (DO-IT) research program. DO-IT is funded by the Royal Dutch Society for Physical Therapy and carried out in collaboration with the Dutch Geriatric Physical Therapy Association. The sponsor had no role in the study design or the collection, analysis, or interpretation of the study data, nor did the sponsor give approval for the manuscript.
- Received March 26, 2012.
- Accepted December 4, 2012.
