Objective: To compare the accuracy of the modified Fried Index (mFI) and the Clinical Frailty Scale (CFS) to predict death or patient-reported new disability 90 days after major elective surgery.
Background: The association of frailty with patient-reported outcomes, and comparisons between preoperative frailty instruments are poorly described.
Methods: This was a prospective multicenter cohort study. We determined frailty status in individuals ≥65 years having elective noncardiac surgery using the mFI and CFS. Outcomes included death or patient-reported new disability (primary); safety incidents, length of stay (LOS), and institutional discharge (secondary); ease of use, usefulness, benefit, clinical importance, and feasibility (tertiary). We measured the adjusted association of frailty with outcomes using regression analysis and compared true positive and false positive rates (TPR/FPR).
Results: Of 702 participants, 645 had complete follow up. The CFS identified 297 (42.3%) with frailty, the mFI 257 (36.6%); 72 (11.1%) died or experienced a new disability. Frailty was significantly associated with the primary outcome (CFS adjusted odds ratio, OR, 2.51, 95% confidence interval, CI, 1.50-4.21; mFI adjusted-OR 2.60, 95% CI 1.57-4.31). TPR and FPR were not significantly different between instruments. Frailty was the only significant predictor of death or new disability in a multivariable analysis. Need for institutional discharge, costs and LOS were significantly increased in individuals with frailty. The CFS was easier to use, required less time and had less missing data.
Conclusions: Older people with frailty are significantly more likely to die or experience a new patient-reported disability after surgery. Clinicians performing frailty assessments before surgery should consider the CFS over the mFI as accuracy was similar, but ease of use and feasibility were higher.