Table 1.

Main characteristics and results on frailty assessment scales for the elderly.

Document	Country	No. of studies included in final analysis	Research design	Year studies were conducted	Main conclusions
Bouillon et al., 2013 (16)	UK	27	Quantitative design: mostly cross-sectional studies	1948 –2011	Twenty-seven frailty scales were identified, but their reliability and validity were rarely evaluated. None of them are used as the gold standard.
Vermeulen et al., 2011 (17)	Netherlands	28	Quantitative design: longitudinal and cohort studies	1975 –2010	The strongest predictors are low physical activity and slow walking speed.
Drubbel et al., 2014 (18)	Netherlands	20	Quantitative design: one cross-sectional survey and 19 cohort studies	2001 –2012	The Frailty Index (FI) is a valid instrument for assessing frailty.
Li et al., 2017 (19)	Canada	Non-systematic literature review	51 references	Not provided	Measuring the grades of frailty in the elderly could assist in the assessment, management, and decision-making for osteoporosis and osteoporotic fractures.
Singh et al., 2014 (20)	US	Non-systematic literature review	101 references	Not provided	There are numerous frailty assessment scales available.
Dawson and Dennison, 2016 (21)	New Zealand	Non-systematic literature review	36 references	Not provided	At present, while diagnostic tools have been developed to identify those with the condition (e.g. the PRISMA 7 questionnaire), as there are many conditions which frailty mimics, the problem of low specificity remains.