. 2018 Dec 29;18:1414. doi: 10.1186/s12889-018-6331-7

Table 2.

Quality assessment (using the EPHPP), intervention type and outcome of reviewed studies N = 23

Study (primary author)	Selection bias	Study design	Confounders	Blinding	Data collection methods	Withdrawals and drop-outs	Global rating	intervention type	Dimension of health literacy	Outcome
Meppelink et al., 2015 [24]	S	S	S	M	S	S	Strong	Web-based intervention	Functional	Functional health literacy
Meppelink et al., 2015 [24]									Critical	Critical health literacy
Elbert et al., 2016 [26]	M	S	S	M	S	W	Moderate	Web-based intervention	Functional	Healthy lifestyle
Gilbert et al., 2012 [27]	M	S	S	S	W	M	Moderate	Tailored information leaflet	Functional	Healthy lifestyle
Gilbert et al., 2012 [27]									Critical
Meppelink et al., 2015 [25]	W	S	S	M	S	M	Moderate	Web-based intervention	Functional	Functional health literacy
Meppelink et al., 2015 [25]									Critical	Critical health literacy
Heasum et al., 2017 [23]	M	S	S	W	S	M	Moderate	Web-based intervention	Functional	Functional health literacy
Sahm et al., 2011 [18]	M	S	S	M	M	W	Moderate	Tailored information leaflet	Functional	Understanding of drug label
Walker et al., 2007 [19]	M	S	S	M	S	W	Moderate	Tailored information leaflet	Functional	Knowledge
Webb et al., 2008 [32]	M	M	W	M	M	M	Moderate	Group-based intervention	Functional	Self-management
									Interactive	Healthy lifestyle
										Health status
										Access to health care
										Ability to make treatment choices
										Symptom recognition and monitoring
Berger et al., 2013 [29]	W	M	W	M	W	M	Weak	Group-based intervention	Critical	Level of critical health literacy
Berger et al., 2013 [29]										Self-management
Blanson Henkeman et al., 2013 [17]	W	S	W	W	S	S	Weak	Individual, personal contact	Functional	Knowledge
Blanson Henkeman et al., 2013 [17]										Self-management
Boxell et al., 2012 [20]	W	M	W	M	S	S	Weak	Tailored information leaflet	Functional	Symptom recognition and monitoring
Garcia-Retamero et al., 2010 [35]	W	M	S	M	M	W	Weak	Web-based intervention	Functional	Understanding of health risk
Galesic et al., 2011 [36]	W	S	W	M	M	W	Weak	Aids to support numerical concepts	Functional	Understanding of health risk
Galesic et al., 2013 [37]	W	S	M	W	W	W	Weak	Aids to support numerical concepts	Functional	Ability to make treatment choices
Haesum et al., 2016 [21]	W	M	W	M	M	S	Weak	Web-based intervention	Functional	Functional health literacy
										Self-management
										Shared decision making
Kasper et al., 2005 [38]	M	M	M	W	M	W	Weak	Aids to support numerical concepts	Functional	Level of functional health literacy
Kasper et al., 2005 [38]										Shared decision making
Lilholt et al., 2016 [22]	M	M	W	M	W	M	Weak	Web-based intervention	Functional	Functional health literacy
										Health status
										Self-management
										Shared decision making
Long et al., 2011 [30]	W	M	W	M	W	W	Weak	Self-management support by call-center	Functional	Knowledge
									Critical	Empowerment
										Self-management
										Critical health literacy
Matic-Strametz et al., 2012 [33]	W	S	W	W	M	S	Weak	Group-based intervention	Functional	Knowledge
Matic-Strametz et al., 2012 [33]									Critical	Critical health literacy
Muller et al., 2017 [34]	W	S	S	M	S	W	Weak	Web-based intervention	Functional	Functional health ltieray
										Healthy lifestyle
										Self-management
Neville et al., 2005 [28]	W	M	W	M	W	W	Weak	Web-based intervention	Functional	Understanding of health risk
								Multi-component programme		Self-management
								Individual, personal contact		Understanding of drugs label
Reiter et al., 2012 [39]	W	M	W	W	W	W	Weak	Group-based intervention	Functional	Knowledge
								Multi-component programme		Healthy lifestyle
										Health status
White et al., 2012 [31]	S	S	W	W	S	W	Weak	Individual, personal contact	Functional	Self-management
									Critical	Ability to make treatment choices
										Access to health care
										Empowerment
										Healthy lifestyle

S strong, M moderate, W weak. Global Rating is calculated using information across all six domains: strong (no weak ratings), moderate (one weak rating), or weak (two or more weak ratings)