Comparison 1: Interventions targeting patients compared with usual care
Observer‐based outcome measure ‐ continuous data		The study not included in the quantitative synthesis supported the pooled result
Studies included in the quantitative synthesis (n = 424)	SMD (95% IC)
LeBlanc 2015a	0.54 (‐0.13 to 1.22)
Maclachlan 2016
LeBlanc 2015b
Tai‐Seale 2016
Observer‐based outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Hamann 2014	n= 100, no difference between the study groups, unclear risk of bias
Haskard 2008	Unit of error analysis
Patient reported outcome measure ‐ continuous data		It is unlikely that the study not included in the quantitative synthesis would change the direction of the effect size estimate given that its sample size is not very large
Studies included in the quantitative synthesis (n = 1386)	SMD (95% IC)
Deen 2012	0.32 (0.16 to 0.48)
Maranda 2014
Pickett 2012
van der Krieke 2013
van Peperstraten 2010
Cooper 2011
Perestelo‐Perez 2016
Tai‐Seale 2016
Eggly 2017
Patient‐reported outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Hamann 2014	n = 100, no difference between the study groups, unclear risk of bias
Patient‐reported outcome measure ‐ categorical data		Van Tol‐Geerdink 2016 does not support the pooled result but given that the pooled estimate of the effect size is in favor of the control group, it is likely that adding this study would move the pooled estimate of the effect size towards a null effect. Wolderslund 2017 does not support the pooled result but given its very large sample size, it is likely that adding this study would move the pooled estimate of the effect size towards a positive effect. Korteland 2017 supports the pooled result (null effect).
Studies included in the quantitative synthesis (n = 754)	RD (95% IC)
Krist 2007	‐0,09 (‐0.19 to 0.01)
Landrey 2012
Murray 2001
Sheridan 2014
Vestala 2013
Vodermaier 2009
Patient‐reported outcome measure ‐ categorical data
Studies not included in the quantitative synthesis	Results
van Tol‐Geerdink 2016	n = 240, significant difference in favor of the intervention group, high risk of bias
Wolderslund 2017	n = 4349, significant difference in favor of the intervention group, high risk of bias
Korteland 2017	n = 155, no difference between the study groups, high risk of bias
Comparison 2. Effect of intervention: Interventions targeting healthcare professionals compared to usual care
Observer‐based outcome measure ‐ continuous data		Murray 2010 and Bernhard 2011 ‐ ANZ (Australia and New Zealand sub‐sample) support the pooled result. Bernhard 2011 ‐ SGA (Switzerland, Germany and Austria sub‐sample) does not support the pooled result but it is unlikely that adding these data to the quantitative synthesis would move the pooled estimate of the effect size toward a null effect or in the opposite direction, given its very small sample size. Moreover, the different results observed in the two sub‐samples is a possible indication of an effect modification
Studies included in the quantitative synthesis (n = 479)	SMD (95% IC)
Fossli 2011	0.70 (0.21 to 1.19)
Shepherd 2011
Stacey 2006
Sanders 2017
Cox 2017
LeBlanc 2015b
Observer‐based outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Bernhard 2011‐ SGA	n = 32, no difference between the study groups, high risk of bias
Bernhard 2011‐ ANZ	n = 21, significant difference in favor of the intervention group, high risk of bias
Murray 2010	n = 88, significant difference in favor of the intervention group, low risk of bias
Patient‐reported outcome measure ‐ continuous data		Légaré 2012 does not support the pooled result. However, it is unlikely that adding these data to the quantitative synthesis would move the pooled estimate of the effect size from the null effect to a significant positive effect.
Studies included in the quantitative synthesis (n = 5772)	SMD (95% IC)
Cooper 2011	0.03 (‐0.15 to 0.20)
Kennedy 2013
Koerner 2014
Tinsel 2013
Wilkes 2013
Patient reported outcome measure ‐ continuous
Studies not included in the quantitative synthesis	Results
Légaré 2012	n = 359, significant difference in favor of the intervention group, unclear risk of bias
Patient ‐reported outcome measure ‐ categorical data		Bernhard 2011 supports the pooled result.
Studies included in the quantitative synthesis (n = 6303)	RD (95% IC)
Légaré 2012	0,01 (‐0.03 to 0.06)
O'Cathain 2002
Patient‐reported outcome measure ‐ categorical
Studies not included in the quantitative synthesis	Results
Bernhard 2011	n = 694, no difference between the study groups, high risk of bias
Comparison 3: Interventions targeting both patients and healthcare professionals compared to usual care
Patient‐reported outcome measure ‐ continous data		Although the confidence interval of the pooled estimate of the effect size contains the null effect, the estimate is in favor of the intervention group. Adding data from Loh 2007 would move the pooled estimate towards a positive effect. Adding Wetzels 2005 would move the result towards a null effect.
Studies included in the quantitative synthesis (n = 1479)	SMD (95% IC)
Cooper 2011	0.13 (‐0.02 to 0.28)
Härter 2015
Hamann 2007
Rise 2012
Wilkes 2013
Tai‐Seale 2016
Epstein 2017
Patient reported outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Loh 2007	n = 405, significant difference in favor of the intervention group, unclear risk of bias
Wetzels 2005	n = 263, no difference between the study groups, high risk of bias
Patient‐reported outcome measure ‐ categorical data		Leighl 2011 supports the pooled result
Studies included in the quantitative synthesis (n = 266)	RD (95% IC)
Mathers 2012	‐0.01 (‐0.20 to 0.19)
Härter 2015
Patient‐reported outcome measure ‐ categorical data
Studies not included in the quantitative synthesis	Results
Leighl 2011	n = 207, no difference between the study groups, unclear risk of bias
Comparison 4: Interventions targeting patients compared to other interventions targeting patients
Patient‐reported outcome measure ‐ continuous data		Lalonde 2006 and Street 1995 support the pooled results
Studies included in the quantitative synthesis (n = 1906)	SMD (95% IC)
Causarano 2014	0.03 (‐0.18 to 0.24)
Deen 2012
Hamann 2011
Schroy 2011
van Roosmalen 2004
Schroy 2016
Adarkwah 2016
Eggly 2017
Hamann 2017
Jouni 2017
Smallwood 2017
Patient‐reported outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Lalonde 2006	n = 26, no difference between study groups, high risk of bias
Street 1995	n = 60, no difference between study groups, high risk of bias
Patient‐reported outcome measure ‐ categorical data		Kopke 2014 and Butow 2004 support the pooled results. Wolderslund 2017 does not support the pooled result but given its very large sample size, it is likely that adding this study would move the pooled estimate of the effect size toward a positive effect.
Studies included in the quantitative synthesis (n = 2272)	RD (95% IC)
Butow 2004	0,03 (‐0.02 to 0.08)
Davison 1997
Deschamps 2004
Dolan 2002
Kasper 2008
Krist 2007
Raynes‐Greenow 2010
Stiggelbout 2008
Thomson 2007
Davison 2002
Patient‐reported outcome measure ‐ categorical data
Studies not included in the quantitative synthesis	Results
Köpke 2014	n = 192, no difference between the study groups, high risk of bias
Butow 2004	n =164, no difference between the study groups, high risk of bias
Wolderslund 2017	n = 4349, significant difference in favor of the intervention group, high risk of bias
Comparison 5: Interventions targeting healthcare professionals compared to other interventions targeting healthcare professionals
Observer‐based outcome measure ‐ continuous data		Contrary to Elwyn 2004, which reported null results, Feng 2013 reported significant positive results. However it is unlikely that combining these two studies would move the estimate of the effect towards a significant positive result. More studies are needed to draw robust conclusions.
Studies included in the quantitative synthesis (n = 20)	SMD (95% IC)
Elwyn 2004	‐0,30 (‐1.19 to 0.59)
Observer‐based outcome measure ‐ continuous data
Studies not included in the quantitative synthesis	Results
Feng 2013	n =118, significant difference in favor of the intervention group, high risk of bias