Table 1 Baseline characteristics of patients with type 2 diabetes in the Fremantle Diabetes Study categorized by quintile of serum bicarbonate

N (%)

183 (14.3)

219 (17.1)

341 (26.6)

178 (13.9)

362 (28.2)

Age (years)

61.9 ± 12.4

62.6 ± 12.8

63.2 ± 10.3

64.3 ± 11.0

66.8 ± 10.1***^{,†††, ‡‡‡}

Male (%)

43.7

38.8

46.9

57.3^†††

54.7^†††

Ethnic background (%)

 Anglo-Celt

65.6

62.6

62.2

60.1

58.8

 Southern European

11.5

16.0

19.4

20.8

18.5

 Other European

10.4

7.3

6.2

10.1

9.4

 Asian

1.1

4.1

3.2

3.4

4.4

 Aboriginal

3.3

1.4

1.2

1.7

0.8

 Mixed/other

8.2

8.7

7.9

3.9

8.0

Not fluent in English (%)

12.0

12.8

17.6

18.5

14.7

Educated beyond primary school (%)

77.3

73.8

75.7

70.5

72.8

Currently married/de facto relationship (%)

62.8

61.0

65.4

68.5

69.0

Alcohol consumption (standard drinks/day)

0 [0–0.8]

0 [0–0.3]

0 [0–0.8]

0 [0.08]

0 [0–0.8]

Smoking status (%)

 Never

38.1

47.0

48.4

48.6

41.2

 Ex-

38.7

39.6

38.3

39.5

44.0

 Current

23.2

13.4

13.4

11.9

14.8

Age at diabetes diagnosis (years)

56.6 ± 12.6

57.0 ± 12.5

57.2 ± 10.8

58.2 ± 11.3

59.6 ± 11.6*

Diabetes duration (years)

3.2 [0.7–8.0]

4.0 [1.0–8.0]

4.0 [1.0–8.0]

4.0 [1.0–10.0]

4.0 [1.1–11.0]

Diabetes treatment (%)

 Diet

27.3

28.0

33.9

31.3

35.1

 Oral glucose-lowering medications (OGLMs)

59.0

64.7

54.3

54.5

51.4

 Insulin ± OGLMs

13.7

7.3

11.8

14.2

13.5

Fasting serum glucose (mmol/L)

8.6 [6.8–11.4]

8.7 [7.0–11.1]

8.3 [6.9–10.8]

8.5 [6.7–11.0]

8.2 [6.6–10.4]

HbA_1c (%)

7.7 [6.6–8.9]

7.4 [6.3–8.9]

7.4 [6.3–8.8]

7.6 [6.3–8.9]

7.3 [6.5–8.8]

HbA_1c (mmol/mol)

61 [49–74]

57 [45–74]

57 [45–73]

60 [45–74]

56 [48–73]

BMI (kg/m²)

30.2 ± 5.7

30.5 ± 5.8

29.8 ± 5.4

29.6 ± 5.2

28.5 ± 5.1**^{,†††, ‡}

Systolic blood pressure (mm Hg)

150 ± 26

149 ± 25

151 ± 24

149 ± 24

152 ± 22

Diastolic blood pressure (mm Hg)

81 ± 12

79 ± 12

81 ± 10

80 ± 11

80 ± 11

Antihypertensive medications (%)

48.1

46.6

51.9

42.7

59.1^†,###

Diuretic therapy (%)

14.8

16.0

16.7

21.9

31.2***^{,†††,‡‡‡}

Serum potassium (mmol/L)

4.5 ± 0.4

4.5 ± 0.4

4.5 ± 0.4

4.5 ± 0.4

4.4 ± 0.5

Serum chloride (mmol/L)

105 ± 3

104 ± 3***

103 ± 3***^,††

102 ± 2***^{,†††,‡}

101 ± 3***^{,†††,‡‡‡,##}

Total serum cholesterol (mmol/L)

5.6 ± 1.5

5.5 ± 1.1

5.5 ± 1.0

5.5 ± 1.1

5.3 ± 1.0*

Serum HDL-cholesterol (mmol/L)

1.04 ± 0.30

1.02 ± 0.31

1.08 ± 0.33

1.06 ± 0.33

1.07 ± 0.33

Serum triglycerides (mmol/L)

2.2 (1.2–4.1)

2.1 (1.2–3.5)

1.9 (1.1–3.2)

1.8 (1.0–3.1)

1.7 (1.1–2.8)***^,††

Lipid-modifying treatment (%)

15.3

9.6

11.7

7.9

8.6

Aspirin therapy (% ≥75 mg/day)

18.6

21.9

20.9

19.7

25.5

Urinary albumin: creatinine ratio (mg/mmol)

3.3 (0.6–17.7)

3.3 (0.8–13.9)

2.9 (0.7–11.4)

3.0 (0.7–14.0)

3.1 (0.7–13.5)

eGFR (CKD-EPI) category (%)

*

*

***

 ≥90 mL/min/1.73 m²

24.6

26.0

26.2

21.9

16.0

 60–89 mL/min/1.73 m²

44.8

51.1

54.1

55.6

56.9

 45–59 mL/min/1.73 m²

14.2

16.9

13.8

17.4

19.9

 30–44 mL/min/1.73 m²

9.8

4.6

4.4

4.5

6.4

 <30 mL/min/1.73 m²

6.6

1.4

1.5

0.6

0.8

Peripheral sensory neuropathy (%)

26.7

34.6

27.6

33.3

32.9

Peripheral arterial disease (%)

28.5

26.2

27.1

25.1

35.7

Coronary heart disease (%)

26.2

29.7

27.3

22.5

36.5^#

Cerebrovascular disease (%)

9.3

8.2

9.7

6.2

13.8

Charlson comorbidity index (%)

 0

71.6

71.7

74.2

79.2

64.9

 1–2

21.3

21.9

20.2

17.4

26.8

 ≥3

7.1

6.4

5.6

3.4

8.3