CFS Validation Study
The original 7-point Clinical Frailty Scale© (CFS) was validated as part of the second wave of the Canadian Study of Health and Aging. The CFS© summarized a standardized history and physical examination structured to contain the key elements of a comprehensive geriatric assessment. Data collection was multidisciplinary (nursing, and a general practitioner, internist, neurologist, psychiatrist or geriatrician). The CFS© was developed to provide these disciplines with a common language and adopted information about grades of frailty that had been validated in the first wave of this large (n>10,000) multisite study.
Below we present a copy of the abstract from the validation paper:
Background: There is no single generally accepted clinical definition of frailty. Previously developed tools to assess frailty that were shown to be predictive of death or need for entry into institutional care had not gained acceptance among practicing clinicians. We aimed to develop a tool that would be both predictive and easy to use.
Methods: We developed the 7-point Clinical Frailty Scale© (CFS) and applied it (and other established tools that measure frailty) to 2305 elderly patients who participated in the second stage of the Canadian Study of Health and Aging (CSHA). We followed this cohort prospectively; after 5 years, we determined the ability of the CFS to predict death or need for institutional care, and correlated the results with those obtained from other established tools.
Results: The CSHA Clinical Frailty Scale was highly correlated (r = 0.80) with the Frailty Index. Each 1-category increment of our scale significantly increased the medium-term risks of death (21.2% within about 70 months, 95% confidence interval [CI] 12.5%–30.6%) and entry into an institution (23.9%, 95% CI 8.8%–41.2%) in multivariable models that adjusted for age, sex and education. Analyses of receiver operating characteristic curves showed that the CFS performed better than measures of cognition, function or comorbidity in assessing risk for death (area under the curve 0.77 for 18-month and 0.70 for 70-month mortality).
Interpretation: Frailty is a valid and clinically important construct that is recognizable by physicians. Clinical judgments about frailty can yield useful predictive information
Rockwood K, Song X, MacKnight C, Bergman H, Hogan DB, McDowell I, Mitnitski A. A global clinical measure of fitness and frailty in elderly people. CMAJ. 2005 Aug 30;173(5):489-95.