Agreement and predictive value of the clinical frailty scale in hospitalized older patients

Our objective was to perform an external validity study of the clinical frailty scale (CFS) classification tree by determining the agreement of the CFS when attributed by a senior geriatrician, a junior geriatrician, or using the classification tree. Additionally, we evaluated the predictive value of the CFS for 6-month mortality after admission to an acute geriatric unit.

This prospective study was conducted in two acute geriatric units in Belgium. The premorbid CFS was determined by a senior and a junior geriatrician based on clinical judgment within the first 72 h of admission. Another junior geriatrician, who did not have a treatment relationship with the patient, scored the CFS using the classification tree. Intra-class correlation coefficient (ICC) was calculated to assess agreement. A ROC curve and Cox regression model determined prognostic value.

In total, 97 patients were included (mean age 86 ± 5.2; 66% female). Agreement of the CFS, when determined by the senior geriatrician and the classification tree, was moderate (ICC 0.526, 95% CI [0.366-0.656]). This is similar to the agreement between the senior and junior geriatricians' CFS (ICC 0.643, 95% CI [0.510-0.746]). The AUC for 6-month mortality based on the CFS by respectively the classification tree, the senior and junior geriatrician was 0.719, 95% CI [0.592-0.846]; 0.774, 95% CI [0.673-0.875]; 0.774, 95% CI [0.665-0.882]. Cox regression analysis indicated that severe or very severe frailty was associated with a higher risk of mortality compared to mild or moderate frailty (hazard ratio respectively 6.274, 95% CI [2.613-15.062] by the classification tree; 3.476, 95% CI [1.531-7.888] by the senior geriatrician; 4.851, 95% CI [1.891-12.442] by the junior geriatrician).

Interrater agreement in CFS scoring on clinical judgment without Comprehensive Geriatric Assessment is moderate. The CFS classification tree can help standardize CFS scoring.