Are Performance Measures Necessary to Predict Loss of Independence in Elderly People?

BACKGROUND

The frailty phenotype (FP) proposed by Fried and colleagues (Fried LP, Tangen CM, Walston J, et al.; Cardiovascular Health Study Collaborative Research Group. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56:M146-M156.) requires the administration of performance tests (gait speed, handgrip strength) not always feasible in routine clinical practice. Furthermore, the discriminative capacity of the instrument has been rarely investigated. Aim of this study was to evaluate the discriminative capacity of the FP and compare it with a modified version including only anamnestic information.

METHODS

Data are from 890 participants of the InCHIANTI study without impairment in activities of daily living (ADL) at baseline (mean age 74 years, women 55%). Frailty was defined by (a) the presence of ≥ 3 criteria of the FP, and (b) having ≥ 2 criteria of an anamnestic FP (AFP), not including gait speed and handgrip strength. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were used to evaluate the discriminative capacity of both definitions for incident disability (ie, loss of at least one ADL), incidence of "accelerated" disability (loss of >2 ADL) over a 6-year follow-up, and 5-years mortality.

RESULTS

FP and AFP yielded a frailty prevalence of 6.4% and 6.5%, respectively; only 32 patients were considered frail by both indices (kappa: .53). For incident disability, FP showed sensitivity = .194, specificity = .963, PPV = .400, and NPV = .903. Similarly, AFP had sensitivity = .129, specificity = .949, PPV = .245, and NPV = .894. Consistent results were found for accelerated disability and mortality.

CONCLUSIONS

In our sample, both FP and AFP showed low sensitivity in identifying older people who would die or develop disability, but they could well discriminate people who would not experience adverse outcomes.