Table 1 Characteristics of all patients in the renal clinics, and a comparison between those who were and were not considered eligible for referral back (BR) to primary care.

Number of patients per hospital

CWH: 102/300 (34.0%)

CWH: 31/102 (30.4%)

CWH: 71/102 (69.6%)

VMC: 100/300 (33.3%)

VMC: 23/100 (23.0%)

VMC: 77/100 (77.0%)

RUMC: 98/300 (32.7%)

RUMC: 24/98 (24.5%)

RUMC:74/98 (75.5%)

 Gender, male (%)

173 (57.5%)

44 (56.4%)

129 (58.1%)

0.794

 Age in years, median (range)

67.5 (19–96)

70 (25–88)

67 (19–96)

0.265

 Number of outpatient visits, mean

3.8 ± 1.66

(n = 259)

3.0 ± 1.28

(n = 76)

4.1 ± 1.69

(n = 183)

< 0.001

 ADPKD*

33/300 (11.0%)

7/78 (9.0%)

26/222 (11.7%)

0.506

 Glomerular diseases¹

82/300 (27.3%)

18/78 (23.1%)

64/222 (28.8%)

0.327

 Systemic diseases²

20/300 (6.7%)

0/78 (0.0%)

20/222 (9.0%)

0.006

 Tubulointerstitial nephritis

11/300 (3.7%)

2/78 (2.6%)

9/222 (4.1%)

0.547

 Drug-induced CKD

7/300 (2.3%)

2/78 (2.6%)

5/222 (2.3%)

0.875

 Vascular CKD

61/300 (20.3%)

19/78 (24.4%)

42/222 (18.9%)

0.304

 Diabetic nephropathy

26/300 (8.7%)

8/78 (10.3%)

18/222 (8.1%)

0.562

 Other cause³

38/300 (12.7%)

11/78 (14.1%)

27/222 (12.2%)

0.658

 Unknown cause

20/300 (6.7%)

11/78 (14.1%)

9/222 (4.1%)

0.002

 eGFR (ml/min/1.73²), mean

42 ± 21.07

46 ± 19.95

40 ± 21.3

0.044

Stage proteinuria, (%)

0.007

 A1

47/296 (15.9%)

15/78 (19.2%)

32/218 (14.7%)

 A2

121/296 (40.9%)

41/78 (52.6%)

80/218 (36.7%)

 A3

128/296 (43.2%)

22/78 (28.2%)

106/218 (48.6%)

Haemoglobin (g/dl), mean

13.21 ± 1.79

(n = 253)

13.54 ± 1.82

(n = 72)

13.05 ± 1.77

(n = 181)

0.054

Potassium (mmol/L), mean

4.5 ± 0.49

(n = 265)

4.4 ± 0.39

(N = 78)

4.5 ± 0,53

(n = 187)

0.865

Phosphate (mmol/L), mean

1.05 ± 0.28

(n = 224)

1.01 ± 0.29

(n = 63)

1.06 ± 0.27

(n = 161)

0.196

Systolic blood pressure (mm Hg), mean

131 ± 16.6

(n = 283)

131 ± 16.49

(n = 76)

131 ± 16.7

(n = 207)

0.967

Diastolic blood pressure (mm Hg), mean

73 ± 9.96

(n = 283)

74 ± 8.37

(n = 76)

73 ± 10.48

(n = 207)

0.424

 Angina pectoris

33/271 (12.2%)

10/77 (13.0%)

23/194 (11.9%)

0.797

 Myocardial infarction

42/272 (15.4%)

16/78 (19.8%)

26/194 (13.4%)

0.142

 Heart failure

30 /270 (11.1%)

15/78 (19.2%)

15/192 (7.8%)

0.007

 Hypertension (K86.87)

180/274 (65.7%)

53/78 (67.9%)

127/196 (64.8%)

0.620

 TIA or CVA

38/272 (14.0%)

17/78 (21.8%)

21/194 (10.8%)

0.018

 Hemiplegia

0/271 (0%)

0/78 (0%)

0/193 (0%)

NA

 Peripheral vascular disease

41/270 (15.2%)

9/77 (11.5%)

32/193 (16.6%)

0.312

 Diabetes mellitus

74/270 (27.4%)

21/77 (27.3%)

53/193 (27.5%)

0.608

 Uncomplicated

35/270 (13.0%)

8/77 (10.4%)

27/193 (14.0%)

 Complicated

39/270 (14.4%)

13/77 (16.9%)

26/193 (13.5%)

 COPD

20/272 (7.4%)

6/78 (7.7%)

14/194 (7.2%)

0.892

 Dementia

0/272 (0%)

0/78 (0%)

0/194 (0%)

NA

 Liver disease

6/270(2.3%)

0/78 (0%)

6/192 (3.1%)

0.288

 Mild

5/270 (1.9%)

0/78 (0%)

5/192 (2.6%)

 Moderate / severe

1/270 (0.4%)

0/78 (0%)

1/192 (0.5%)

 HIV or AIDS

1/271 (0.3%)

0/77 (0%)

1/194 (0.5%)

0.528

 Cancer

53/269 (19.7%)

13/77 (16.9%)

40/192 (20.8%)

0.042

 Solid tumour

51/269 (19%)

11/77 (14.3%)

40/192 (20.8%)

 Metastatic

2/269 (0.7%)

2/77 (2.6%)

0/192 (0%)

 Haematological malignancy

4/269 (1.5%)

0/78 (0%)

4/191 (2.1%)

0.198

 Connective tissue disease

21/273 (7.7%)

4/77 (5.2%)

17/196 (8.7%)

0.332

 Peptic ulcer

6/271 (2.2%)

2/77 (2.6%)

4/194 (2.1%)

0.787

Charlson Comorbidity Index, median (range)

5.3 (0–15)

(n = 219)

5.3 (0–15)

(n = 69)

5.3 (0–12)

(n = 150)

0.938

 Angiotensin receptor blockers

186/272 (68.4%)

50/78 (64.1%)

136/194 (70.1%)

0.336

 Diuretics

92/269 (34.2%)

25/76 (32.9%)

67/193 (34.7%)

0.777

 Beta blockers

130/272 (47.8%)

38/78 (48.7%)

92/194 (47.4%)

0.847

 Calcium channel blockers

105/272 (38.6%)

25/78 (32.1%)

80/194 (41.2%)

0.159

 Vitamin D / alfacalcidol

151/271 (55.7%)

39/78 (50.0%)

112/193 (58.0%)

0.228

 Erythropoeitin

19/272 (6.3%)

4/78 (5.1%)

15/194 (7.7%)

0.446

 Phosphate binders

10/272 (3.7%)

0/78 (0%)

10/194 (5.2%)

0.041

 Immunosuppressive drugs

67/300 (22.3%)

0/78 (0%)

67/222 (30.2%)

< 0.001