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Table 1 Demographic and clinical characteristics of the study cohort

From: Converting from face-to-face to postal follow-up and its effects on participant retention, response rates and errors: lessons from the EQUAL study in the UK

Characteristics

All UK EQUAL participants (n = 506a)

Alive and invited to EFU (n = 238a)

Consented to EFU (n = 113a)

Did not consent to EFU (n = 125)

Responded to EFU (n = 60a)

Did not respond to EFU (n = 41a)

Died before EFU survey (n = 12)

Age, median (IQR) years

76.7 (70.8–81.7)

74.7 (69.0–80.4)

75.1 (68.9–80.5)

74.3 (70.0–79.8)

73.2 (68.2–79.7)

77.0 (70.5–81.1)

76.6 (71.0–82.5)

Sex, n (%)

       

Male

312 (62)

154 (65)

75 (66)

79 (63)

35 (58)

29 (71)

11 (92)

Female

192 (38)

82 (35)

36 (32)

46 (37)

24 (40)

11 (27)

1 (8)

Ethnicity, n (%)

       

White

459 (91)

215 (90)

107 (95)

108 (86)

57 (95)

38 (93)

12 (100)

Black: Caribbean

10 (2)

3 (1)

1 (1)

2 (2)

0

1 (2)

0

Black: African

24 (5)

12 (5)

2 (2)

10 (8)

1 (2)

1 (2)

0

Black: (other)

5 (1)

4 (2)

0

4 (3)

0

0

0

Asian: Chinese

6 (1)

2 (1)

1 (1)

1 (1)

1 (2)

0

0

Marital status, n (%)

       

Married/ living together

205 (41)

116 (49)

64 (57)

52 (42)

34 (57)

23 (56)

7 (58)

Divorced/ separated

29 (6)

17 (7)

9 (8)

8 (6)

7 (12)

0

2 (17)

Widowed/ partner has died

90 (18)

43 (18)

17 (15)

26 (21)

9 (15)

6 (15)

2 (16)

Never married/ lived with partner

21 (4)

9 (4)

6 (5)

3 (2)

2 (3)

3 (7)

1 (8)

Blank

159 (31)

51 (21)

15 (13)

36 (29)

7 (12)

8 (20)

0

Educational Class, n (%)

       

Primary school

154 (30)

84 (35)

40 (35)

43 (34)

19 (32)

18 (44)

3 (25)

Secondary school or vocational course

137 (27)

78 (33)

46 (41)

32 (26)

26 (43)

12 (29)

8 (67)

University degree

34 (7)

15 (6.5)

8 (7)

7 (6)

6 (10)

2 (5)

0

Other

3 (1)

1 (0.5)

1 (1)

0

0

1 (2)

0

Unanswered

176 (35)

59 (25)

16 (14)

43 (34)

8 (13)

7 (17)

1 (8)

BMI (kg/m2), mean ± SD

29.2 (23.6–34.8)

29.4 (23.7–35.1)

29.5 (23.6–35.4)

29.2 (23.8–34.7)

30.2 (23.4–37.0)

29.4 (24.3–34.4)

27.0 (23.2–30.9)

eGFR, median (IQR)

18.7 (16.5–19.9)

19.0 (17.0–20.0)

19.0 (17.0–20.0)

19.0 (17.0–20.0)

18.8 (17.0–20.0)

19.0 (16.9–20.0)

18.8 (15.0–20.0)

PRD, n (%)

       

Glomerular disease

34 (7)

15 (6)

11 (10)

4 (3)

9 (15)

2 (5)

0

Tubulo-interstitial disease

49 (10)

31 (13)

16 (14)

15 (12)

10 (17)

5 (12)

1 (8)

Systemic disease affecting the kidney

21 (4)

10 (4)

5 (4)

5 (4)

2 (3)

2 (5)

1 (8)

Diabetes

99 (20)

44 (18)

19 (17)

25 (20)

8 (13)

10 (24)

1 (8)

Hypertension

68 (13)

35 (15)

15 (13)

20 (16)

9 (15)

4 (10)

2 (17)

Familial/ hereditary nephropathies

12 (2)

6 (3)

2 (2)

4 (3)

1 (2)

1 (2)

0

Miscellaneous renal disorders

104 (21)

45 (19)

21 (19)

24 (19)

8 (13)

9 (22)

4 (33)

Unknown/ missing

117 (23)

50 (21)

22 (19)

28 (22)

12 (20)

7 (17)

3 (25)

Years since diagnosis, median (IQR)

3.0 (1.0–6.0)

2 (1–6)

2.0 (1.0–6.0)

3.0 (1.0–7.5)

2.5 (1.0–6.0)

2.0 (1.0–4.3)

2.5 (1.0–4.3)

Co-morbidities, n (%)

       

Diabetes

193 (38)

81 (34)

31 (27)

50 (40)

14 (23)

14 (34)

3 (25)

Hypertension

386 (76)

179 (75)

81 (72)

98 (78)

40 (67)

30 (73)

11 (92)

History of Major Vascular Event

194 (38)

83 (35)

28 (25)

55 (44)

12 (20)

12 (29)

4 (33)

Malignancy

110 (22)

45 (19)

20 (18)

25 (20)

10 (17)

8 (20)

2 (17)

Blank

15 (3)

5 (2)

4 (4)

1 (1)

3 (5)

1 (2)

0

Charlson Index, mean ± SD

7.0 (5.2–8.8)

6.63 (4.91–8.36)

6.4 (4.7–8.0)

6.9 (5.1–8.6)

6.1 (4.4–7.8)

6.6 (5.0–8.2)

6.8 (4.9–8.6)

  1. History of major vascular event includes stroke, myocardial infarction, heart failure and amputation due to peripheral vascular disease. aInitial demographic and clinical details were unavailable for two participants joining in EFU; one who responded and one who consented but did not respond to EFU