Table 1.

Characteristics of selected studies (n = 41)

Characteristics	n	%	References
Country
The Netherlands	13	31.7	[40–50, 60, 65]
Italy	8	19.5	[38, 39, 52, 55, 57, 58, 61, 66]
Germany1	6	14.6	[12, 13, 20–31, 36, 62, 64, 67, 68]
France1	6	14.6	[33–35, 51, 63, 69, 70]
UK	4	9.8	[53, 54, 56, 71]
Denmark	2	4.9	[72, 73]
Croatia	1	2.4	[37]
Belgium	1	2.4	[74]
Study design
Retrospective cohort1	19	46.3	[13, 25–27, 36, 40, 41, 44–51, 57, 62, 66, 71, 73]
Cross-sectional	13	31.7	[37–39, 42, 52–55, 58, 63–65, 70]
Non-controlled before-after	5	12.2	[35, 59–61, 69]
Prospective cohort1	2	4.9	[29–31, 74]
Case study1	1	2.4	[32–34]
Other (qualitative)	1	2.4	[56]
Publication yeara
1999–2008	12	21.1	[35, 38, 39, 41, 45, 46, 52, 53, 60, 69, 71]
2009–2011	13	22.8	[13, 21, 24, 25, 32, 40, 50, 51, 58, 63–66]
2012–2014	11	19.3	[12, 22, 26, 33, 34, 42, 48, 55, 61, 68, 70]
2015–2017	16	28.1	[20, 23, 27, 28, 30, 31, 43, 44, 47, 49, 56, 59, 62, 67, 72, 74]
2018–2019	5	8.8	[29, 36, 37, 54, 73]
Guideline scopeb
Treatment1	31	75.6	[12, 13, 20–30, 32, 35, 36, 40, 41, 43–45, 47, 48, 50, 51, 57–64, 66, 68, 69, 71–74]
Follow-up	4	9.8	[35, 42, 55, 57, 58, 69]
Preventive measures	4	9.8	[37, 49, 53, 56, 70, 74]
Diagnosis	4	9.8	[35, 58, 61, 65]
Risk of biasc
Low	25	62.5	[13, 30, 35, 36, 40–44, 46, 48, 49, 55–58, 61, 65, 66, 70–72, 74, 75]
Moderate	14	35.0	[37–39, 45, 47, 50–54, 59, 60, 63, 69]
High	1	2.5	[64]

¹Reported in more than one separate publications

^aPercentages calculated over the total number of publications (n = 57)

^bThe total exceeds 100% since some guidelines comprised more than one scope

^cPercentages over 40 studies, a case study was not evaluated