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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