The Power of HbA1c

For anyone with diabetes, the HbA1c test is the one test that really gives an insight as to how their diabetes is being managed. For me as a health care professional, I find the HbA1c a particularly motivating tool in my practice. It opens up a discussion as to how people who have reached good HbA1c’s have achieved their goal. For those who are struggling to reach their targets, it leads to questions such as how can we help, or what is going wrong? I have a Siemens DCA Analsyer in my practice, which works by taking a blood sugar, as you would at home, passing it through a machine, and you have your HbA1c reading in 6 minutes. For those who attend my practice, it has become one of the main reasons why they attend, as knowing exactly what your HbA1c level is, gives you the power to make changes if you can, before attending your GP/Diabetes team appointments. I see how soul destroying many of these appointments are and the effects they have on people with diabetes, and how judgmental health care professionals can be despite all your best efforts.

So what is a HbA1c? 

In the blood stream are the red blood cells, which are made of a molecule, haemoglobin. Glucose sticks to the haemoglobin to make a ‘glycosylated haemoglobin’ molecule, called haemoglobin A1C or HbA1C. The more glucose in the blood, the more haemoglobin A1C or HbA1C will be present in the blood. Red cells live for 8 -12 weeks before they are replaced. By measuring the HbA1C it can tell you how high your blood glucose has been on average over the last 8-12 weeks. It is important to remember that a HbA1c is not the same as a blood glucose level.

Most people will know this test as their three monthly average of their blood sugar readings. I always compare it to their blood sugar readings, they are like a camera, taking a snapshot of a moment in time, your HbA1c is like a video recorder, filming constantly over a three month period. If you have type 2 diabetes, many people may only check their blood sugars once or twice a week, first thing in the morning, or before meals. These blood sugars will normally be at their best first thing in the morning, or before meals, so they do not reflect accurately how your diabetes is doing. Your blood sugars maybe rising two hours after eating when the carbohydrates are breaking down and releasing sugar into your blood stream, and if these readings are high, they will cause your HbA1c to rise. Many people in my practice are surprised when their HbA1c reading comes back raised, despite having what they would consider good blood sugars. More than likely they are fitting into the above scenario.

What Should my HbA1c be?

As most people will be aware by now, the HbA1c level of measurement has changed since last year to meet with international measurements and guidelines. Instead of being measured in percentages, it is now measured in mmol/mol. Like going from old money to new money, I still talk in percentages with my clients until they become familiar with the new measurements and for the purpose of this blog I will stick to that.

Depending on what guidelines or lab results you read, every HbA1c target is different. Lab results give a parameter under your actual HbA1c reading for[pull_quote align=”left”]Your HbA1c target is a shared decision, reached by you and your diabetes team. Individualized targets are now very much in vogue, their is no longer one size fits all[/pull_quote] example 4.5 – 6%. This is not an actual guideline of what you need to achieve, and for me, this is where much confusion lies. Those parameters are how the laboratory actually calculates your HbA1c and not a real reflection on your own target. Your HbA1c target is a shared decision, reached by you and your diabetes team. Individualized targets are now very much in vogue, their is no longer one size fits all. All the research points to achieving a HbA1c of under 7% as giving you the best possible chance of avoiding many of the complications of diabetes which I agree with. Previously a target of 6.5% existed and depending on what guidelines and diabetes team you attended or possibly still do, they insist on setting low targets that are difficult, I believe, for alot of people with diabetes to achieve. the expect you to achieve these targets without putting the necessary supports in place to help you.

Aggressive treatment of diabetes for a lot of people with diabetes, especially the elderly, is counterproductive. A study called the ACCORD study discovered that by driving HbA1c’s down to fast and too aggressively increased the rate of cardiovascular events in certain people, because their body could not cope with the stress of too low a blood sugar. For many people who have HbA1c’s of under 6.5% maybe having many hypos’s especially of they are on insulin and may not be detecting them. Other conditions that can affect a HbA1c result are anaemia and haemochromotosis.

What Affects my HbA1c levels? 

As previously mentioned, people who have diabetes and suffer from anaemia and haemochromotosis may have altered or inaccurate HbA1c levels. But what else can affect your levels that you may not be aware of? The following can alter your HbA1c level so it is important to discuss these with your diabetes team if they concern you:

  • Alcoholism
  • Taking large doses of aspirin
  • Taking large levels of opiate drugs
  • High levels of triglycerides (bad cholesterol) in the blood
  • High levels of uremia in the blood/chronic kidney disease
  • High levels of bilirubin in the blood
  • Vitamin C
  • Vitamin E
  • Steroids
  • Thiazide Diuretics
  • Some anti psychotics
  • Some herbal mixtures
  • Phenytoin
  • Some oestrogen compounds
  • Some antibiotics actually lower blood sugar levels
Below is a conversion chart for the new HbA1c measurements.

5

6

7

8

9

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

5.0

5.1

5.2

5.3

5.4

5.5

5.6

5.7

5.8

5.9

31

32

33

34

36

37

38

39

40

41

6.0

6.1

6.2

6.3

6.4

        6.5†,‡

6.6

6.7

6.8

6.9

42

43

44

45

46

48

49

50

51

52

7.0§

7.1

7.2

7.3

7.4

        7.5†,‡

7.6

7.7

7.8

7.9

53

54

55

56

57

58

60

61

62

63

8.0

8.1

8.2

8.3

8.4

8.5

8.6

8.7

8.8

8.9

64

65

66

67

68

69

70

72

73

74

9.0

9.1

9.2

9.3

9.4

9.5

9.6

9.7

9.8

9.9

75

76

77

78

79

80

81

83

84

85

10

11

12

13

14

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

DCCT (%)

IFCC (mmol/mol)

10.0

10.1

10.2

10.3

10.4

10.5

10.6

10.7

10.8

10.9

86

87

88

89

90

91

92

93

95

96

11.0

11.1

11.2

11.3

11.4

11.5

11.6

11.7

11.8

11.9

97

98

99

100

101

102

103

104

105

107

12.0

12.1

12.2

12.3

12.4

12.5

12.6

12.7

12.8

12.9

108

109

110

111

112

113

114

115

116

117

13.0

13.1

13.2

13.3

13.4

13.5

13.6

13.7

13.8

13.9

119

120

121

122

123

124

125

126

127

128

14.0

14.1

14.2

14.3

14.4

14.5

14.6

14.7

14.8

14.9

130

131

132

133

134

135

136

137

138

139

If you are concerned or worried about your HbA1c talk to your diabetes team, or contact us at Diabetes Insight, where you will be treated in a confidential and respectful manner without fear of judgement.
For additional support and advice you can attend our practice based in the Cork Health & Lifestyle Centre, Blackrock, Cork where we offer HbA1c testing. This open referral service catering for people with diabetes from the Republic of Ireland. Contact Helena on (086) 1739287 &/or email: hfarrell77@gmail.com for further information.

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