Table 2

Included articles and annual registry reports with extracted data

ID	Lead author (year)	Format	No of reminders	RR (%) at follow-up points					Total follow-up time (years)	Change in RR (%/year)*
ID	Lead author (year)	Format	No of reminders	#0	#1	#2	#3	#4	Total follow-up time (years)	Change in RR (%/year)*
Database searches—prospective cohort studies
1	Ahmed†27	Paper	1	90	85	82			2	−4.0
2	Ashley‡28	Mix	>1		85	70	66		1.25	−25.3
3	Blanchard29	ND	ND	99	85	82	81	50	4	−11.0
4	Blanchard29	ND	ND	99	70	57	44	45	4	−13.5
5	Gjeilo30	Paper	1	100	89	89	82		5	−3.6
6	Pieterse†31	Paper	>1		86	81			2	−5.0
Database searches—registry-based studies
7	Helsten§,‡32	Mix	>1		62	71			1	9.1
8	Imam‡16	Paper	>1	99	91	89	83	79	2	−10.1
9	Olsson33	Paper	1	88	82				8	−0.7
10	Porchet†34	Paper	>1	87	98	91			1	4.0
11	Simony35	Paper	1	100	84				1	−15.8
Registry articles
12	Bengtsson36	Paper	1		93	87			5	−1.2
13	Elkan¶,‡24	Paper	1	78	73	62			2	−8.0
14	Elkan¶,‡24	Paper	1	100	98	99			2	−0.6
15	Gjertsen37	Paper	0		54	49			1	−7.5
16	Kvist38	Mix	>1	66	50	48	48		5	−3.6
17				61	49	47	46			−3.0
18				72	40	47	38			−6.8
19				68	38	46	38			−6.0
20				61	45	45	42			−3.8
21				58	43	44	42			−3.2
22	Lind†39	Web	0	46	31				1	−15.0
23	Rahr-Wagner†40	Web	0	33	27				1	−6.5
Registry reports
24	SweSpine†,§41	Mix	ND		71	57	44		5	−6.7
25	Danish†42	Web	0	37	31				1	−5.4
26	Danish Hip Arthroscopy Reg42	Web	>1	52	56	48	34		3	−6.0
27	DaneSpine†,**43	Paper	1		83	73	59		5	−5.9
28	DaneSpine†,**43	Paper	1		48	37	24		5	−6.0
29	Swedish Fracture Reg †,§42	Paper	1	55	41				1	−13.7
30	Swedish Hip Arthroplasty Reg†,¶42	Mix	1	83	88				1	4.4
31	Swedish Knee Ligament Reg†25	Mix	1	67	50	47	45	39	10	−2.7
32	Swedish Knee Ligament Reg†25	Mix	1	62	48	47	44	38	10	−2.3
33	Norwegian Hip Fracture Reg†44	Paper	0		57	57	55		3	−0.6
34	UK National Ligament Reg45	Mix	ND	58	35	30			2	−14.0
35	UK National Joint Registry†,¶,§46	Paper	>1	42	44				0.5	4.3
36				100	75	61	84		3	−5.1
37				100	76				0.5	−48.2
38	New Zealand ACL-Reg†,**23	Mix	>1	100	86	80	86		2	−7.0
39	New Zealand ACL-Reg†,**23	Mix	>1	100	85	77	83		2	−8.5
40	Norwegian Knee Ligament Reg†,**	Paper	1		62	58	59		10	−0.4

Follow-up point #0 is the reported baseline time point or time of intervention as specified in the article or report. The subsequent time point intervals (#2, #3…) vary for each article or report and is not the follow-up year. Articles or reports with multiple rows represent separate subgroups with individual RRs reported within the article.
*This is calculated by taking the difference between the last and first RRs and dividing it by the number of follow-up years between the last and first reported RR to show the average change in RR per year.
†Author/registry emailed for reminders and/or format information.ID 1, Rens Kempeneers, Feb 2019 (personal communication); ID 6, Moniek ter Kuile, Feb 2019 (personal communication); ID 10, Anne Mannion, Feb 2019 (personal communication); ID 22, 23, 25, Martin Lind, Feb 2019 (personal communication); ID 27, 28, Karen H. Hansen, Feb 2019 (personal communication); ID 29, Karin Pettersson, Feb 2019 (personal communication); ID 30, Sandra Olausson, Feb 2019 (personal communication); ID 31, 32, Anna Pappas, Feb 2019 (personal communication); ID 33, Kari A. Vågstøl, Feb 2019 (personal communication); ID 35, 36, 37, Beth at NJR Helpdesk, Feb 2019 (personal communication); ID 38, 39, Charlotte Smith, Feb 2019 (personal communication); ID 40, Anne M. Fenstad, Feb 2019 (personal communication).
‡Registry emailed about RRs. ID 27, 28, Karen H. Hansen, Feb 2019 (personal communication); ID 38, 39, Charlotte Smith, Feb 2019 (personal communication); ID 40, Anne M. Fenstad, Feb 2019 (personal communication).
§Some or all RRs calculated by author using numbers available in article or report.
¶Follow-up questionnaires only sent to previous responders.
**Change in number of PROMs or questions sent at subsequent follow-ups.
ND, not determined; PROMs, patient-reported outcome measures; RR, response rate.