Subjective and objectives measures of frailty among adults with advanced chronic kidney disease: a cross-sectional analysis of clinician misclassification

Background: Frailty is a recognisable clinical measure of impaired physiological reserve and vulnerability to adverse outcomes that is validated among patients with kidney disease. Practice patterns reveal inconsistent use of objective frailty measures by nephrologists, with clinicians prioritising subjective clinical impressions, possibly risking misclassification and discrimination.

Aims: The aim of this study was to examine correlations between subjective and objective measures of frailty in a cohort of patients attending routine nephrologist review.

Methods: Eighty-nine participants attending scheduled review with their primary treating nephrologist (n = 6) were included in cross-sectional analysis. Measured frailty based on Fried phenotype and subjective clinician impression were assessed for congruence using Pearson's correlation analysis and ĸ statistic. Ordinal logistic regression examined patient demographics associated with perceived frailty. Misclassification was explored using descriptive statistics and contingency table analysis.

Results: Frailty and prefrailty were prevalent by both objective and subjective means of assessment with minimal correlation between clinician impression and measured Fried phenotype (r = 0.50, P = 0.00, ĸ = 0.25, P = 0.00). Subjective clinician impression misclassified half of participants, influenced by surrogate frailty measures including female sex, comorbidity and reliance on a walking aid. Clinicians were equally likely to over-classify prefrailty as to under-recognise established frailty, with no evidence of systemic misclassification bias. Subjective clinican impression of frailty had a positive predictive value of 19.1% and a negative predictive value of 56.2%.

Conclusions: Nephrologists' reliance on subjective clinical impressions that overlook or misclassify prefrailty offers incomplete prognostic assessment and potentially misses opportunities for early intervention.