2. DIABETES AND THE HEART
Q1: A previously well 60-year-old lady is admitted
with an acute anterior myocardial infarction.
A random blood glucose concentration was
found to be 12.1 mmol/L (<6.7),subsequently she
was confirmed to have type 2 diabetes.
What is the optimal management of her blood
sugar?
3. DIGAMI
INTENSIVE INSULIN THERAPY DURING AND
AFTER MYOCARDIAL INFARCTION
People with diabetes who suffer an acute myocardial
infarction (MI) are at markedly increased risk of future
cardiovascular morbidity and mortality. The DIGAMI
study compared "conventional" anti-diabetic therapy
to intensive insulin therapy consisting of acute insulin
infusion during the early hours of MI and thrice-daily
subcutaneous insulin injection for the remainder of
the hospital stay and a minimum of 3 months
thereafter. Although there was an overall reduction in
adverse outcomes in patients receiving the intensive
insulin regimen, it is unclear which component (the IV
insulin infusion or the intensive chronic therapy) was
responsible!!!
4. DIGAMI 2
Conclusion DIGAMI 2 did not support the fact that an
acutely introduced, long-term insulin treatment improves
survival in type 2 diabetic patients following myocardial
infarction when compared with a conventional
management at similar levels of glucose control or that
insulin-based treatment lowers the number of non-fatal
myocardial re-infarctions and strokes. However, an
epidemiological analysis confirms that the glucose level
is a strong, independent predictor of long-term mortality
in this patient category, underlining that glucose control
seems to be an important part of their management.
5. ACCORD
ACTION TO CONTROL CARDIOVASCULAR RISK
IN DIABETES
Conclusions
As compared with standard therapy, the use of intensive
therapy to target normal glycated hemoglobin levels for
3.5 years increased mortality and did not significantly
reduce major cardiovascular events. These findings
identify a previously unrecognized harm of intensive
glucose lowering in high-risk patients with type 2
diabetes. (ClinicalTrials.gov number, NCT00000620.)
6. ANSWER 1
1. INSULIN THERAPY DURING ACUTE MI
2. CONVENTIONAL ANTI DIABETIC TREATMENT,TAILORED FOR THE
PATIENT ACCORDING TO THE GUIDELINES AS SOON AS POSSIBLE.
3. WATCH FOR CONTRAINDICATIONS
4. DO NOT AIM AT TIGHT GLYCEMIC CONTROL, SINCE THIS IS
ASSOCIATED WITH INCREASED CV MORBIDITY(HBA1C)
METFORMIN CONTRAINDICATIONS:
Stop if serum concentration of creatinine is higher than 150
micromols/l.
Withdraw during periods of suspected tissue hypoxia (for example,
due to myocardial infarction, sepsis).Any body knows when to start
(Is it after 2 weeks?)
Withdraw for three days after contrast medium containing iodine
has been given, and start treatment with metformin only after renal
function has been checked.
Withdraw two days before general anesthesia and reinstate when
renal function is stable.
7. CONTRAINDICATIONS TO
SULPHONYLUREAS
Known hypersensitivity to the particular sulfonylurea or components in
their formulation
Sulfonylureas should generally be avoided in pregnancy( Pregnancy
Category: C)
Glynase and Micronase are Pregnancy Category B
Some drugs may interact with S/U causing hypoglycemia(eg. Fluconazole)
8. A 56-year-old male type 2 diabetic of 15 years attends the diabetic clinic for
annual review.
He has been treated with insulin for 5 years and tells you his blood sugar
readings have been steady with fasting readings of less than 7.0 pre breakfast.
He does complain of increased lethargy however for approximately 6 months.
There are no symptoms suggestive of angina or intermittent claudication,
however he reports parasthesia affecting the lower limbs, which is worse at
night. He attends annually for digital imaging of the retina and is reported to
have changes of background diabetic retinopathy in both eyes. He has
previously documented micro-albuminuria. There is no complaint of erectile
dysfunction.
On examination his weight is 80 kg and pulse rate is 72/min with a blood
pressure of 145/85 mmHg. He appears clinically euthyroid with no palpable
goiter. S1S2 are audible with no added sounds or murmurs; his chest is clear to
auscultation and his abdomen is soft with no organomegaly. He has diminished
128 Hz tuning fork vibration and 10 g monofilament sensation in both of his feet
with intact pedal pulses and no evidence of ulceration. Fasting blood glucose is
7.8 mmol/L (3.0-6.0).
9. HbA1c
60 mmol/mol
7.6%
Sodium
140 mmol/L
Potassium
4.0 mmol/L
Urea
7.8 mmol/L
Creatinine
135 µmol/L
Liver function tests Normal
Haemoglobin
110 g/L
MCV
83.0 fL
White cell count
10 ×109/L
Platelets
205 ×109/L
Total Cholesterol
4.9 mmol/L
HDL Cholesterol
1.0 mmol/L
LDL Cholesterol
2.5 mmol/L
Triglycerides
2.2 mmol/L
Estimated
Glomerular
Filtration Rate
50 ml/min/1.73 m2
Microa-lbumin
screen
45 mg/mmol
How would you approach this patient?
10. This patient has type 2 diabetes complicated by the micro-vascular complications of
diabetes. He has incipient diabetic nephropathy as evidenced by micro-albuminuria,
hypertension and a reduction in estimated GFR. The risk of progression to overt
nephropathy is high.
There is good evidence that control of blood pressure to <125/75 mmHg and use of
Angiotensin receptor blocking drugs such as Irbesartan can retard the progression to
macro-albuminuria in Type 2 diabetic subjects1.
There is evidence for ACE inhibitors such as Ramipril in type 1 diabetes. However the
starting dose is usually lower and titrated up as per the patient is able to tolerate.
The LDL-C cholesterol lever is reasonable, however a target of <2.0 is more likely to be
achieved with a more potent statin such as Atorvastatin or Rosuvastatin rather than
increasing the dose of Simvastatin.
HbA1c is above target however metformin is relatively contraindicated with a e-GFR
below 60 due to risk of lactic acidosis and pioglitazone would not be the ideal choice
given the possibility of exacerbating fluid retention.
Moderation of diet and lifestyle changes as well and maybe increasing insulin would be
the means of improving glycaemic control.
Reference:
1. Parving HH, et al. The effect of irbesartan on the development of diabetic nephropathy
in patients with type 2 diabetes. N Engl J Med. 2001;345(12):870-8.
11. DM AND RAMADAN
A 50-year-old woman was diagnosed with type 2 diabetes
six months ago.
Her diabetes is well controlled on metformin 1000 mg
twice a day.
She plans to fast during the daytime in the month of
Ramadan, and have two large meals (one meal in the
evening at sunset and one in the early morning at dawn).
What is the best course of action that this patient should
take regarding her diabetes during Ramadan?
12. What is the main issue?
Risk of hypoglycemia, If low risk
patients can fast
Patients may need to monitor their
blood sugars more frequently.
Does taking blood samples for
sugar break the fast?
13. TYPES OF INSULIN
A 32-year-old male physical education teacher
has a three year history of type 1 diabetes.
At the last annual review, his HbA1c was 51
mmol/mol but he complains of hypoglycemic
events particularly during exercise. He has been
commenced on the insulin analogue, aspart
insulin.
Compared with conventional short-acting insulins
what is the advantage of insulin analogue
therapy?
14. Answer:
Short-acting insulin analogue, like lispro-insulin,
aspart insulin and glulisine insulin have a rapid
onset of action and a shorter duration of action
than conventional short-acting soluble insulins.
Consequently studies reveal reduced postprandial glucose excursions versus soluble
insulin and potentially a reduced incidence of
hypoglycemia although the evidence for this is
debated.
15. DIAGNOSIS OF DIABETES
An asymptomatic 56-year-old man with a family
history of type 2 diabetes was found to have a
fasting venous glucose of 6.5 mmol/l. What is
the management of this patient?
16. ANSWER
According to the new revised criteria for the diagnosis of
diabetes, venous plasma glucose (VPG) of 6.1 mmol/l - 6.9
mmol/l is categorised as impaired fasting glycaemia and
requires further assessment with a 75 gram oral glucose
tolerance test (OGT) which is still the gold standard.
A two hour value of equal to or over 11.1 mmol/l is diagnostic
of diabetes.
Impaired glucose tolerance is a two hour VPG of 7.8 mmol/l 11.1 mmol/l during an OGT.
Initial treatment of type 2 diabetes is patient education, diet
and lifestyle changes.How to manage if he is found to have
impaired glucose tolerance? What is his annual risk of
developing type 2 diabetes?
17. PATHOPHYSIOLOGY OF DIABETES
A 75-year-old man is admitted with a blood sugar of
40 mmol/l and lobar pneumonia and dies despite
treatment.
Post-mortem examination reports the presence of
amyloid polypeptide on pancreatic histology.
What would this suggest?
18. ANSWER
The presence of amyloid polypeptide on pancreatic
histology is highly suggestive of type 2 diabetes.
Although the primary defect in type 2 diabetes is insulin
resistance, loss of insulin secretory function over time
does occur in patients with type 2 diabetes, and
reduction in beta cell mass due to amyloid deposition
may partly account for this.
What about other types of diabetes? Type1, MODY and
LADA?
19. You are consulted by a 52-year-old man with type
2 diabetes diagnosed for one year.
His blood pressure is 156/88 mmHg, his
cholesterol is 5.3 mmol/L (<5.2), he has a BMI of
29 kg/m2 and does not smoke. His HbA1c is 63
mmol/mol (20-42), he currently takes only
metformin 500 mg bd.
What is the single intervention most likely to
reduce his overall risk of both micro-vascular
and macro-vascular events?
20. Note this question asks about reducing both micro and macro-vascular
complications. The best evidence seems to be for multifactorial intensive
therapy as in the Steno studies from Denmark. However, in this question,
as worded, BP is the simplest answer.
Trials have shown that antihypertensive therapy reduces the risk of
cardiovascular events and micro-vascular complications. The intensity of
the treatment is currently of debate.
Lowering HbA1c only resulted in a significant reduction in micro-vascular
events and, in some trials after a longer period, shows cardiovascular
benefit. However, the trial showed an excess of deaths in the intensive
glycemic control arm perhaps because the intensification occurred later in
the course of the disease when cardiovascular disease was present and
may have put participants at increased risk from hypoglycemia.
Lipid lowering therapy benefits patients with diabetes as much as those
without diabetes in preventing macro-vascular events in sub- group
analyses but has no effect on micro-vascular events demonstrated so far.
Adding fibrate may have an effect on retinopathy.
Aspirin is recommended to type 2 patients with one other cardiovascular
risk factor but there is little trial evidence of efficacy.
Weight reduction may reduce progression to overt diabetes from states of
impaired glucose tolerance but has not been demonstrated to reduce
micro-vascular risk in diabetes.
21. Diabetes UK recommended that treatment for type 2
diabetics should have the following aims (as a result of
UKPDS findings):
Blood pressure of 140/80 mmHg or below
Specific targets of BP for certain situations.
HbA1c levels of 7.5% (58 mmol/mol) or below
Fasting blood glucose levels of 4-7 mmol/litre
Self monitored blood glucose levels before meals of
between 4 and 7 mmol/l
22. A 45-year-old obese male with a two year history of type
2 diabetes has recently commenced metformin at a dose
of 500 mg twice daily.
However, he re-attends clinic and reports numerous
gastrointestinal side effects including bloating and
flatulence. He is keen to stop metformin and commence
an alternative agent.
What alternative medications you will offer?
23. Treatment options for type 2 diabetes are complex.
Metformin is indicated in patients who are overweight or obese, whose blood glucose is
inadequately controlled with lifestyle interventions. It can also be first-line in patients
who are not overweight.
If blood glucose control remains inadequate another oral hypoglycaemia should be
added, usually a sulphonylurea. Gradual increases in the dose of metformin reduces the
risk of side effects, and modified release preparations reduce the risk further. The dose
should be reviewed if the creatinine excess 130mmol/L or the eGFR is below 45, and
stopped with a creatinine over 150mmol/L or eGFR below 30.
Sulphonylureas can be used as first-line if the patient is not overweight, metformin is
contraindicated or not tolerated, or a rapid response to therapy is required. Patients
should be warned of the risk of hypoglycaemia.
Thiazolidinediones are used in patients who have inadequate glycaemic control with a
combination of metformin and sulphonylurea, in whom there are concerns regarding
insulin therapy (e.g. where there is likely to be significant insulin resistance). They can be
associated with significant oedema and weight gain, and should not be used in those
with heart failure or those at high risk of fracture. This class of drugs interacts with
PPARy receptors and can significantly reduce insulin resistance. They can be used in
combination with sulphonylureas for patients who are intolerant of metformin.
Acarbose is only indicated in those patients unable to use other oral glucose-lowering
medications.
24. Exenatide can be used just prior to insulin in patients with a BMI of over 35.
Repaglinide is an insulin secretagogue, which can be used if other classes of
treatment fail.
Insulin is typically only started in patients who have failed an adequate trial
of oral glucose-lowering treatments.
References & Further Reading:
NICE. Type 2 diabetes (CG66).
NICE. Type 2 Diabetes - newer agents (CG87).
25. A 72-year-old male diabetic presents with weakness and lethargy.
He was diagnosed with type 2 diabetes mellitus 12 years ago and remains on
gliclazide and metformin therapy and takes atenolol for hypertension. There is
little to find on examination.
Blood pressure 164/88 mmHg lying and standing
Serum sodium 135 mmol/L (137-144)
Non-haemolysed serum potassium 5.7 mmol/L (3.5-5.5)
Urea 8.3 mmol/L (2.5-7.5)
Serum creatinine 141 µmol/L (60-110)
Plasma glucose 10.1 mmol/L (3.0-6.0)
HbA1c 62 mmol/mol (20-42)
7.8% (3.8-6.4)
He has loss of pin prick and vibration sensation to the ankle in both legs and a
background diabetic retinopathy.
What is the likely cause for these electrolyte abnormalities?
26. This patient has chronic kidney disease which is likely to
be related to diabetic nephropathy and longstanding
hypertension.
The electrolyte abnormalities show a lowish sodium
concentration and raised potassium. In conjunction with
the renal impairment this would suggest a diagnosis of
hyporeninaemic hypoaldosteronism (type IV renal
tubular acidosis). This is not uncommon in elderly
diabetic patients and is associated with the nephropathy.
The hyperkalaemia is usually mild but may be
exacerbated by drugs such as beta-blockers and ACE
inhibitors.
Treatment is usually successful with conservative
measures such as stopping provocatory agents, a low
potassium diet. Small doses of fludrocortisone could be
considered for refractory cases.
27. A 55-year-old woman is found to have ++ glycosuria and had a maternal
history of type 2 diabetes mellitus. She is a smoker of 20 cigarettes per day.
Examination reveals no specific abnormalities apart from a BMI of 30. Blood
pressure was 132/88 mmHg.
Investigations reveal:
Serum creatinine 80 µmol/L (60-110)
Plasma glucose (fasting) 11.3 mmol/L (3.0-6.0)
Total serum cholesterol 5.5 mmol/L (<5.2)
HDL cholesterol 1.4 mmol/L (>1.55)
What is most likely to improve her life expectancy?
28. She is diabetic and obese as defined by her BMI of 30.
She is most prone to risk of cardiovascular disease with evidence suggesting that
people
with diabetes have at least a two- to fourfold increased cardiovascular mortality.
In terms of improving life expectancy, of the risk factors mentioned, diabetes, mild
dyslipidaemia and hypertension, stopping smoking would, without question, be expected
to have the greatest benefit.
Tight glycaemic control unfortunately does little to reduce cardiovascular risk (United
Kingdom prospective diabetes study [UKPDS]) and statin therapy would be expected to
have a small but significant impact in this patient according to primary prevention
studies (West of Scotland Coronary Prevention Study [WOSCOPS]).
29. Stopping smoking is the first priority, even if it causes further weight gain.
Smoking is associated with a cardiovascular risk of six times in women and
three times in men. Stopping smoking (after a myocardial infarction [MI])
reduces the risk of recurrent MI by 50%.
Reference:
1.Njølstad I, et al. Smoking, serum lipids, blood pressure, and sex differences
in myocardial infarction. A 12-year follow-up of the Finnmark Study.
Circulation. 1996;93(3):450-6.
2.Prescott E, et al. Smoking and risk of myocardial infarction in women and
men: longitudinal population study. BMJ. 1998;316(7137):1043-7.
30. A 58-year-old male with a three year history of type 2 diabetes mellitus (T2DM)
is referred to the diabetic clinic. He is currently on diet control alone for his
diabetes.
He has been generally well but has been aware of a 6 kg weight gain over the
last one year together with two to three episodes of nocturia most nights. He
is an ex-smoker and drinks approximately 8 units of alcohol weekly.
On examination he has a body mass index of 33.5 kg/m2, a blood pressure of
162/98 mmHg and a pulse of 78 beats per minute. Fundoscopy reveals
scattered microaneurysms in both eyes and a crescent of hard exudates
encroaching upon the macula in the right eye. Neurological examination
reveals reduced light touch sensation in both feet to the ankles.
Dipstick of his urine reveals protein (++) and glucose (+).
Investigations show:
31. Fasting plasma glucose
7.8 mmol/L
(3.0-6.0)
Sodium
138 mmol/L
(137-144)
Potassium
4.2 mmol/L
(3.5-4.9)
Urea
7.8 mmol/L
(2.5-7.5)
Creatinine
90 µmol/L
(60-110)
62 mmol/mol
(20-46)
7.8%
(3.8-6.4)
Cholesterol
4.0 mmol/L
(<5.2)
Triglycerides
2.5 mmol/L
(0.45-1.69)
HbA1c
WHAT IS THE MOST APPROPRIATE TREATMENT TO REDUCE HIS
CARDIOVASCULAR (CV) RISK?
32. The most appropriate treatment to reduce his cardiovascular risk should focus
on adequate blood pressure control, supported by evidence from UKPDS
which showed greater reductions in CV risk with blood pressure control, as
compared with no overall reduction in CV mortality in patients with tight
glycaemic control on insulin or sulphonylureas.
The NICE guidelines for management of Hypertension (CG127) recommend
the use of an ACE inhibitor as first line antihypertensive in patients under the
age of 55-years-old and a calcium channel blocker for patients more than 55years-old. In this patient with proteinuria however, there is a good rationale for
using an ACE inhibitor despite his age.
Weight reduction has itself not been shown to reduce CV risk, and as yet no
studies have demonstrated this with orlistat.
Statins are recommended for patients with T2DM but the degree of benefit is
often higher when the baseline cholesterol is elevated.
33. This patient has a cholesterol of 4 mmol/l. The NICE guidelines (CG 67 Lipid
modification) recommend aiming for cholesterol <4 mmol/L and LDL-C <2
mmol/L in diabetic patients.
Insulin would worsen weight gain and is not considered first line treatment for
T2DM. Metformin should generally be tried first. Although metformin would be
expected to reduce CV risk in obese patients with type 2 diabetes, a larger
benefit is seen with blood pressure control.
References:
1.Intensive blood-glucose control with sulphonylureas or insulin compared
with conventional treatment and risk of complications in patients with type 2
diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group.
Lancet. 1998;352(9131):837-53.
2.Yusuf S, et al. Effects of an angiotensin-converting-enzyme inhibitor,
ramipril, on cardiovascular events in high-risk patients. The Heart Outcomes
Prevention Evaluation Study Investigators. N Engl J Med. 2000;342(3):145-53.
34. A 70-year-old male with a five year history of type 2
diabetes mellitus (T2DM) presents for annual review with
a blood pressure of (BP)188/88 mmHg.
Clinical examination was normal.
An ECG reveals evidence of left ventricular hypertrophy
(LVH).
What drug is the most appropriate treatment for this
patient's hypertension?
35. Regarding the British Hypertension Society guidelines and NICE
guidelines on the treatment of BP in Type 2 Diabetes, this elderly male
with diabetes has isolated systolic hypertension associated with LVH
(LVH being defined as a complication of hypertension).
Evidence would support the use of a calcium channel blocker and/or
angiotensin-converting enzyme inhibitor (ACEi) as first line.
In a diabetic patient with evidence of nephropathy or any patient with
LVH there is compelling evidence to suggest that ACEI or angiotensin II
receptor blockers should be first line treatment for hypertension.
Reference:
Williams B, et al. British Hypertension Society guidelines for
hypertension management 2004 (BHS-IV): summary. BMJ.
2004;328(7440):634-40.
36. A 43-year-old male is diagnosed with diabetic
nephropathy.
If this patient had type 1 diabetes his chances of
progressing to end stage renal disease (ESRD) would be
approximately 50%.
What percentage of type 2 diabetics with diabetic
nephropathy would be expected to progress to ESRD?
37. Although the incidence of diabetic nephropathy is less
in type 2 diabetics as approximately 90-95% of all
diabetics are type 2s, the majority of patients with
diabetic nephropathy are type 2 diabetics.
There are a number of stages in the development of
nephropathy with glomerular hyperfiltration being an
early feature. Nephropathy itself is signalled by the
excretion of trace amounts of protein in the urine
microalbuminuria.
The progression of the disease may be attenuated by
stringent blood pressure control (with an angiotensinconverting enzyme inhibitor [ACEi]) and strict
glycaemic control.
38. A 52-year-old male with a history of dyslipidaemia and
hypertension attends the surgery for a 75 g oral glucose
tolerance test (OGTT) as part of his cardiovascular risk
assessment and screening for type 2 diabetes.
He is overweight with a BMI of 29 kg/m2, his blood
pressure is 135/85 mmHg on a combination of amlodipine
and perindopril.
His venous plasma OGTT result is as follows.
0 minutes 6.3 mmol/L (3.0-6.0)
120 minutes 10.4 mmol/L (3.0-6.0)
How do you interpret these results?
39. The WHO guidelines are used to make a formal diagnosis of diabetes mellitus. These require the symptoms of diabetes
to be present (polyuria, polydipsia and unexplained weight loss), plus:
A random venous plasma glucose of >11.1 mmol/L
A fasting plasma glucose of >7 mmol/L (whole blood >6.1 mmol/L) OR
A two hour plasma glucose concentration of >11.1 mmol/L two hours after 75 g anhydrous glucose in an oral glucose
tolerance test (OGTT).
With no symptoms a diagnosis requires two confirmatory samples on separate occasions. If the fasting or random
values are not diagnostic, the two hour value should be used.
The WHO guidelines for the diagnosis of diabetes mellitus were updated in 2011. This update states that the HbA1c
(glycosylated haemoglobin) can be used for diagnosis, as long as assays are standardised and no exclusion criteria
are met. Such exclusions include children, patients suspected of having type 1 diabetes, patients with symptoms for
less than two months, patients who are acutely ill, patients taking steroids or antipsychotics (which can cause a rapid
glucose rise), patients with acute pancreatic damage and pregnant patients.
An HbA1c of 48 mmol/mol (6.5%) is recommended as the cut off point for a diagnosis of diabetes. A value of less than
this does not preclude a diagnosis made using the traditional WHO criteria. If patients are asymptomatic, the HbA1c
should be repeated. If this value is less than 48 mmol/mol the patient should be treated as high risk for developing
diabetes, and the test should be repeated in 6 months (or sooner if symptoms develop).
Impaired glucose tolerance (IGT) is defined as a stage of impaired glucose regulation. It is diagnosed if the fasting
plasma glucose is less than 7 mmol/L and the OGTT two hour value is more than 7.8 mmol/L but less than 11.1 mmol/L.
If this diagnosis is present, the patient cannot be described as having impaired fasting glycaemia.
Impaired fasting glycaemic (IFG) describes those individuals who have fasting glucose values above the normal range
but below those diagnostic of diabetes, i.e. fasting plasma glucose >6.1 mmol/L but <7 mmol/L. In the UK it is generally
recommended that these patients have an OGTT to exclude the diagnosis of diabetes. In addition, they should be
actively managed with lifestyle advice and monitored for the development of diabetes.
40. DIABETES AND PREGNANCY
A diagnosis of diabetes mellitus is being considered in 32year-old woman who is 16 weeks pregnant. Her body mass
index (BMI) was 22 kg/m2 (18 - 25).
A 75g oral glucose tolerance test (OGTT) revealed:
Time Plasma glucose concentration
0 hr 6.0 mmol/L (3.0-6.0)
2 hr 12.5 mmol/L (<11.1)
What is the most appropriate step in the management of
this patient?
41. Risk factors for gestational diabetes are BMI >30 kg/m2, previous macrosomic
baby (>4.5 kg), previous gestational diabetes, first-degree relative with
diabetes, ethnic origin (South Asian, Caribbean, Middle Eastern). Screening
with fasting plasma glucose, random blood glucose, glucose challenge tests
and urinalysis is recommended for any women with one of these risk factors.
The 2-hour 75 g oral glucose tolerance test is used to definitively diagnose
gestational diabetes. This is performed at 16-18 weeks in women who have
been affected in a previous pregnancy (with home BM monitoring prior to this,
and a repeat test at 28 weeks if this is normal) and 24-28 weeks for women with
any other risk factor.
If it is safely achievable, women with gestational diabetes should aim to keep
fasting blood glucose between 3.5-5.9 mmol/L and one hour postprandial blood
glucose below 7.8 mmol/L during pregnancy. It is important to note HbA1c
should not be routinely used to monitor glycaemic control in the second and
third trimesters.
Most gestational diabetes will respond to changes in diet and exercise. Only 1020% of women need oral hypoglycaemia agents or insulin therapy. Women
should therefore be given dietary advice, and those with a pre-pregnancy BMI
of >27 should be advised to restrict calorie intake and exercise for at least 30
minutes daily.
42. Hypoglycaemic therapy should be considered for women in whom diet and exercise fails
to maintain blood glucose targets during a period of 1-2 weeks. If there is any evidence
of fetal macrosomia therapy should be initiated immediately. Treatment should be
tailored to the individual women, but in general may include oral hypoglycaemics
(metformin and glibenclamide) and insulin. There is insufficient evidence regarding longacting insulin analogues, and isophane insulin therefore remains the first choice for longacting insulin during pregnancy. Insulin aspart and lispro are safe rapid-acting
analogues.
Women with insulin-treated gestational diabetes should be advised of the risk of
hypoglycaemia (which they may be unaware of) and provided with a concentrated
glucose solution.
During labour and birth, capillary blood glucose would be monitored on an hourly basis
in patients with diabetes and maintained between 4 and 7 mmol/L. This may require the
use of a sliding scale.
In this patient diet and exercise has not yet been trialled, and there is no mention of
foetal macrosomia. Metformin can then be started if glycaemic control is not achieved
within 1-2 weeks. Waiting another four weeks to instigate therapy exposes both mother
and foetus to potential harm. Insulin can be used if glycaemic control is not achieved
with metformin. Glipizide is not used in pregnancy.
References:
NICE. Diabetes in pregnancy (CG63)
43. Which of the following is correct according to the
current criteria for diagnosing diabetes in an
asymptomatic patient?
A. 75 g oral glucose test (OGT) is mandatory for
diagnosing diabetes
B. A fasting venous plasma concentration of <6.9 can
be ignored
C. A single fasting venous plasma glucose
concentration of >7 mmol/L can be used to diagnose
diabetes
D. Impaired glucose tolerance is signified by a venous
glucose concentration of <7 mmol and >11.1 mmol
E. Two separate fasting venous plasma glucose
concentration of >7 mmol/L are diagnostic of diabetes
44. In an asymptomatic individual, a single sample alone is
not sufficient for diagnosis.
Diabetes can be diagnosed if separate fasting samples
show above 7 mmol/L. 75 g.
OGT is still the gold standard for diagnosing diabetes,
although fasting glucose can be used, provided adequate
fast is ensured.
Fasting glucose of above 6.1 but below 6.9 is classed as
impaired fasting glycaemia, which is a new category of
glycaemia. IGT = 7.8 - 11.1