Reliability and validity of a frailty assessment tool in specialised burn care, a retrospective multicentre cohort study

Rationale: There is a trend towards global ageing, and an increasingly number of elderly will be admitted to Dutch burn centres. Elderly patients need different care in comparison to younger patients because, among other reasons, they can be less resilient and frail. Little is known about the precise causes of frailty and its role in care for the elderly. At this moment, insight in the specific needs and outcomes of elderly in specialized burn care is limited. Especially the assesment and treatment of frailty is hardly studied. Multiple frailty assessment instruments are available. An often used frailty assessment instrument is the Canadian Study on Health and Aging Clinical Frailty Scale (CFS) (1)This easely understandeble short instrument is available in Dutch (CFS-NL) and has been validated in Dutch ICU patients. This seems to be a valuable instrument to asses frailty in Dutch burn care, however, the reliability and validity of this instrument in burn patients is unknown.
Objective: The objective is to assess the inter-rater reliability, and construct validity (discriminative, convergent validity, and predictive validity) of the CFS-NL in patients admitted to the Dutch specialized burn centres.
Study design: A retrospective multicentre cohort study using data from the 3 Dutch burn centres in the Netherlands from 2015-2018.
Study population: All patients admitted to a Dutch specializes burn care centre aged 50 years and over in a 4 year period (2015-2018, n=594 patients).
Patients with an admission due to scar related reconstructions, admission for surgery only, and elective one day admissions will be excluded.
Intervention (if applicable): Not applicable.
Main study parameters/endpoints: The inter-rater reliability, and construct validity (discriminative, convergent validity, and predictive validity) of pre-burn frailty scores, using the CFS-NL on admission.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The burden and risks for participants are nil as only data from an existing database (the Dutch Burn Repository R3) and electronic patient records will be used.

CFS-NL is a good tool to score frailty in elderly burn patients

The CFS has been introduced in the second clinical examination of the Canadian Study of Health and Aging (CSHA) as a way to summarize the overall level of fitness or frailty of an older adult after he/she had been evaluated by an experienced clinician. It is not a questionnaire, but a way to summarize information from a clinical encounter with an older person, and it is useful to roughly quantify the overall health status of an individual by the clinician. (1, 17) The CFS is an easy categorisation tool based on simple visual descriptions. The CFS divides patients into 9 classes from fit to terminally ill. These scores are often classified in four groups ranging from fit (CFS1-3), vulnerable (CFS 4), frail (5-8), to terminally ill (CFS=9). See figure 1.
The interrater reliability of this scale will be tested by comparing the individually obtained scores of two independent raters. This will be assessed in at least one burn centre; if research team capacity is available reliability will be assessed in other burn centres as well. Relevant measures of agreement will be calculated.

Validity:
First, we will compare frailty scores between groups with and without comorbidity, and younger versus older patients (<70 years or 70 years and over), to asses discriminative validity/known groups validity. We hypothesize higher frailty scores in patients with comorbidity and in older patients.
Second, we will study the convergent validity of the CFS by comparing the CFS scores to the outcomes of the frailty screening, which is one out of 10 themes of the Dutch National Patient Safety Programme (VMS veiligheidsprogramma).

not applicable