Defining frailty for healthcare practice and research: A qualitative systematic review with thematic analysis

Objective: To identify and examine definitions of frailty using qualitative thematic analysis.

Design: A qualitative meta-aggregative systematic review.

Data sources: The database search was performed using ASSIA, CINAHL, Cochrane Library, Embase, PsycINFO, PubMed and Google Scholar databases. Studies providing definitions of frailty, published in English from 1^st January 2000 to 25^th July 2018 were included.

Review methods: Data were extracted by independent reviewers for qualitative thematic analysis.

Results: In total, 86 studies met inclusion criteria. Five major themes with specific sub-themes were identified following thematic analysis including: (1) types of definitions (operational, conceptual, theoretical, older adults' perspective); (2) characteristics of frailty (a multi-domain and dimensional state, deficits/decline, weakness, a continuum-dynamic concept, clinically identifiable); (3) associated factors (age, comorbidity, nutrition, sarcopenia, social networks and environment); (4) mechanism (reduced adaptability, hormonal dysregulation); and (5) changes in health status and adverse outcomes (disability, increased risk of mortality, other healthcare related outcomes such as increased dependency or risk of falls).

Conclusions: Several themes were found that defined frailty, focusing predominantly on operational definitions and frailty as a physical syndrome. A universally accepted standard definition, which includes all dimensions of frailty is currently warranted.