Feasibility and construct validity of a Frailty index for patients with chronic kidney disease.

Aim: To determine whether the frailty status of patients with chronic kidney disease (CKD) can be measured using a Frailty index (FI).

Methods: One hundred and eleven attending a nephrology clinic were approached to complete a one-page questionnaire evaluating cognitive, psychological and functional status. Data were coded as deficits, summed and divided by the total number of deficits considered, to derive an FI-CKD.

Results: One hundred and ten (mean age 65.2 years) agreed to participate and assessments took approximately 10 minutes to complete. Mean FI-CKD was 0.25 (SD 0.12). The FI-CKD increased with age at 3% per year, correlated with a modified Fried phenotype (P < 0.001) and increased significantly across CKD stages (P = 0.04).

Conclusions: The FI-CKD is feasible in the outpatient setting and has good construct validity. The greater granularity of a continuous measure has the potential to inform decision-making regarding appropriate interventions for patients at the 'frail' end of the health spectrum.