Clinical frailty scale: Inter-rater reliability of retrospective scoring in emergency abdominal surgery.

Background: Frailty is a complex syndrome shown to be an independent predictor of morbidity and mortality after surgery in older patients. Frailty scoring may, therefore, be important, for example, for pre-operative risk assessment and prognosis estimation. The Clinical Frailty Scale (CFS) has been developed to help operationalize frailty in the individual patient. However, the inter-rater reliability of retrospective CFS scoring through patient records by health care personnel is currently unknown in patients over 80 years of age undergoing emergency abdominal surgery.

Methods: Retrospective review of electronic patient journal of 112 patients over 80 years of age undergoing emergency abdominal surgery between 2015 and 2016. Three researchers individually assigned each patient a CFS score. The inter-rater reliability was assessed using Cohen's weighted kappa for the comparison of pairs of assessors, as well as Kendall's coefficient of concordance for the comparison of all three raters simultaneously.

Results: The agreement across raters was strong, with Cohen's kappa values ranging between 0.74 and 0.85 and a Kendall's coefficient of concordance of 0.86.

Conclusions: The inter-rater reliability of assigned CFS from patient journals seems acceptable. This could permit retrospective research utilizing CFS measures from several raters and across centers.