Table 2.

Critical appraisal of included studies using Downs and Black (n = 6).

	Reporting										External validity			Internal validity
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27
Study	Hypothesis/ Aims	Outcome measures	Patient characteristics	Interventions	Distribution of confounders	Main findings	Estimation of random variability	Adverse events	Attrition	Actual probability values	Generalisable population	Subjects selected representative	Intervention representative	Blinding of subjects	Blinding of assessors	Data dredging results	Analysis adjustment for follow-up	Appropriate statistical tests	Compliance to intervention reliable	Valid reliable outcome measures	Same population	Same period of time	Randomised to intervention group	Randomised concealment	Adjustment for confounders	Attrition explained	Sufficient power calculation met	Total score X/28
Atkinson et al., 2005	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	U	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	27
Kim et al., 2015	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	×	U	✓	✓	✓	✓	✓	✓	✓	×	×	✓	✓	✓	24
Lin et al., 2020	✓	✓	✓	✓	✓	✓	✓	×	✓	✓	✓	✓	✓	×	×	✓	✓	✓	✓	✓	✓	✓	✓	×	✓	✓	×	23
Rosengren et al., 2013	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	×	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	27
Widgerow et al., 2009	✓	✓	×	✓	×	✓	✓	×	×	✓	U	U	✓	×	U	✓	✓	✓	✓	✓	✓	✓	✓	×	U	U	U	15

✓, yes; ×, no; U, unable to determine.