A Comparison of Patient Self-Reported Fatigue in the FRAIL Scale With a Validated Fatigue Measure.

Rationale: The FRAIL scale is a self-administered tool used to screen for frailty in clinical, community and long-term nursing settings. Patient's self-reporting of fatigue in the FRAIL scale may raise concerns of subjectivity and accuracy in frailty assessment.

Objective: To assess the performance of the patient-reported fatigue measure in the FRAIL scale in comparison to a validated fatigue measure, the Fatigue Severity Scale (FSS).

Methods: We conducted a cross-sectional study involving interviews and medical records review. Participants were 55 years and older seen at an ambulatory geriatric osteoporosis clinic. Participants were administered the FRAIL scale and the FSS over the phone or in person. Patient self-reported fatigue was derived from the first item (Are you fatigued?) on the FRAIL scale while the FSS provided a validated fatigue measure. Clinical and demographic data were obtained by review of medical records. Sensitivity, specificity, negative and positive predictive values, and AUC were estimated for patient self-reported fatigue from the FRAIL scale using the FSS as the gold standard. Logistic regression analysis was used to investigate independent associations between the items on the FRAIL scale and fatigue assessed by the FSS, adjusting for demographic and clinical characteristics.

Results: We interviewed 126 participants, mean age was 77.2 ± 8.5 years, 91.3% (116) were female and 69.3% (88) were Caucasian/White. The prevalence of fatigue assessed by the FSS and the FRAIL scale were 24% and 34.6%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of patient-reported fatigue were 0.67, 0.75, 0.45, and 0.88, respectively. The AUC was 0.71. Depression (OR = 2.41, 95% CI = 1.14-10.25) and patient self-reported fatigue (OR = 4.74, 95% CI = 1.74-12.9) were significantly associated with FSS fatigue measure.

Conclusion: Patient-reported fatigue largely reflects validated measure of fatigue. Physicians should therefore be encouraged to use the FRAIL scale to assess frailty.