General practice management of type 2 diabetes

Issues under debate
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☰ Table of contents

Issue – Diagnostic criteria for GDM

ADIPS guidelines significantly lower diagnostic threshold

ADIPS guidelines are not accepted by the RACGP due to the need for high-quality evidence and implications for resource utilisation270

Issue – Postnatal screening for type 2 diabetes mellitus

ADIPS guidelines have significantly increase screening frequency

ADIPS guidelines are not accepted by the RACGP due to the need for high-quality evidence and implications for resource utilisation

Screening remains as in the RACGP’s Guidelines for preventive activities in general practice, 8th edition (Red Book) – fasting blood glucose every three years

Postpartum oral glucose tolerance test should be performed every three years


Comparison tables of RACGP (preferred) and ADIPS (alternative) criteria

Screening and diagnosis of gestational diabetes mellitus  (on the basis of a 75 g oral glucose tolerance test)

 

The Royal Australian College of General  Practitioners (RACGP; preferred criteria)

Australian Diabetes in Pregnancy Society (ADIPS; alternative criteria)

Fasting plasma glucose ≥5.5 mmol/L, or two-hour plasma glucose or random glucose ≥8.0 mmol/L

Fasting plasma glucose 5.1–6.9 mmol/L, or one-hour post ≥10.0 mmol/L, or two-hour 8.5–11.0 mmol/L


Follow-up of patients with a history of gestational diabetes mellitus

 

The Royal Australian College of General  Practitioners (RACGP; preferred criteria)

Australian Diabetes in Pregnancy Society (ADIPS; alternative criteria)

75 g two-hour oral glucose tolerance test at 6–12 weeks postpartum

75 g two-hour oral glucose tolerance test, at 6–12 weeks postpartum

Thereafter, a fasting blood glucose or glycated haemoglobin (HbA1c) test every three years

 

The frequency and nature of this surveillance will depend on future pregnancy plans and the perceived risk of converting to type 2 diabetes. Women contemplating another pregnancy should have an oral glucose tolerance test annually

In patients with GDM, hypoglycaemia may have serious effects on placental function and the fetus. Thorough investigation is required in such patients.

Aim to achieve blood glucose levels:

  • between 4 and 6 mmol/L preprandially
  • <7 mmol/L two hours postprandially.

Issue – Blood pressure targets in diabetes management

Guidelines routinely advocate blood pressure (BP) target of systolic blood pressure (SBP) ≤130 mmHg

BP-lowering reduces cardiovascular events and mortality in people with type 2 diabetes. However, the target levels for BP therapy have been based on little direct evidence. Meta-analyses demonstrate that more intensive BP control (SBP ≤130 mmHg) was only associated with further reduction in stroke. A 40% increase in serious adverse events was observed

The target level for optimum BP remains controversial

A number of international guidelines have changed their blood pressure targets to <140/90 mmHg, while others remain at <130/80 mmHg. The target levels for BP therapy have been based on little direct evidence. A number of meta-analyses have demonstrated that the benefits of intensive BP control needs to be balanced with the risks. One meta-analysis demonstrated that more intensive BP control (SBP ≤130 mmHg) compared with usual (<140/90 mmHg) was associated with further reduction in stroke only, but there was a 40% increase in serious adverse events.153 Two additional meta-analyses have recently been published. The analysis by Emdin at al48 found that risk reduction
was attenuated in SBP <140 mmHg. However, there did appear to be lower risk of stroke, retinopathy and albuminuria when blood pressure was reduced to <130 mmHg. A more recent meta-analysis, however, found that treatment of SBP <140 mmHg was associated with increased cardiovascular disease (CVD) death.154 This may in part be related to the selection of trials in this analysis, which included patients with comorbidites such as chronic kidney disease (CKD), heart failure and CVD155

In line with these findings, it would be reasonable for GPs to shift the BP target to <140/90 mmHg for people with diabetes, with lower targets considered for younger people and those at high risk of stroke (secondary prevention) as long as treatment burden is not high. The target BP for people with diabetes and microalbuminuria or proteinuria remains <130/80 mmHg. As always, treatment targets should be individualised and people with diabetes monitored for side effects from use of medications to achieve lower targets

Issue – Screening for adults aged 40–70 years who are overweight or obese

The US Preventive Services Task Force (USPSTF) has recently recommended screening for abnormal blood glucose as part of cardiovascular disease (CVD) risk assessment in adults aged 40–70 years who are overweight or obese. Clinicians should offer or refer patients with abnormal blood glucose to intensive behavioural counselling interventions to promote a healthful diet and physical activity (USPSTF Grade B recommendation)271

This recommendation applies to such adults seen in primary care settings who do not have symptoms of diabetes. The target population includes persons who are most likely to have glucose abnormalities that are associated with increased CVD risk and can be expected to benefit from primary prevention of CVD through risk factor modification

Issue – Target HbA1c levels

The National Institute for Health and Clinical Excellence Quality and Outcomes Framework (NICEQOF) in the UK changed the glycated haemoglobin (HbA1c) target from 7.0% to 7.5% because of the several large trials showing harm with a target that is too low. Because of the measurement error, a range around that mean of, for example, 6.5–8% would be needed. This will allow for measurement variation as well as some individualisation and negotiation with the patient, in a more person-centred approach

Issue – Other

Is an estimated glomerular filtration rate (eGFR) 45–60 m2/min/1.73 m2 of any clinical consequence?

• Use of the Problem areas in diabetes (PAID)/Patient health questionnaire-2 (PHQ-2) tools to detect depression and distress in diabetes and linkage to long-term improved outcomes and complication reduction
• Are there possible benefits of low carbohydrate diets in diabetes management?272

• Reduction in carbohydrate intake has been shown to translate into lower glycaemic excursions and lower overall glycaemic load273–275
–– A recent study has highlighted the benefits of a very low carbohydrate, high unsaturated fat, low saturated fat diet versus a high carbohydrate, low fat diet. The investigators evaluated weight loss, glycaemic control and cardiovascular disease risk factors in patients with type 2 diabetes after 52 weeks. With the likely pathophysiological interaction between carbohydrate and hyperglycaemia, this approach may be considered when more evidence is available.276
The definition of a low-carbohydrate diet varies across the spectrum of studies, causing difficulty in generalising results –– Care may need to be exercised with patients on sodium glucose co-transporter 2 (SGLT2) inhibitors due to risks if ketoacidosis277

 


Diabetes Australian and RACGP logo's
 
 
  1. Johnson B, Abraham M, Conway J, et al. Partnering with patients and families to design a patient- and family-centered health care system: Recommendations and promising practices. Bethesda, MD: Institute for Patient- and Family-Centered Care, 2008.
  2. Emdin CA, Rahimi K, Neal B, Callender T, Perkovic V, Patel A. Blood pressure lowering in type 2 diabetes: A systematic review and meta-analysis. JAMA 2015;313(6):603–15.
  3. Bangalore S, Kumar S, Lobach I, Messerli FH. Blood pressure targets in subjects with type 2 diabetes mellitus/impaired fasting glucose: Observations from traditional and bayesian randomeffects meta-analyses of randomized trials. Circulation 2011;123(24):2799–810, 9 p following 810.
  4. Brunstrom M, Carlberg B. Effect of antihypertensive treatment at different blood pressure levels in patients with diabetes mellitus: Systematic review and meta-analyses. BMJ 2016;352:i717.
  5. Ettehad D, Emdin CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death: A systematic review and meta-analysis. Lancet 2016;387(10022):957–67.
  6. Kevat DA, Sinha AK, McLean AG. Lower treatment targets for gestational diabetes: Is lower really better? Med J Aust 2014;201(4):204–07.
  7. Siu AL. Screening for abnormal blood glucose and type 2 diabetes mellitus: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2015;163(11):861–68.
  8. Ajala O, English P, Pinkney J. Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr 2013;97(3):505–16.
  9. Volek JS, Fernandez ML, Feinman RD, Phinney SD. Dietary carbohydrate restriction induces a unique metabolic state positively affecting atherogenic dyslipidemia, fatty acid partitioning, and metabolic syndrome. Prog Lipid Res 2008;47(5):307–18.
  10. Feinman RD. Fad diets in the treatment of diabetes. Curr Diab Rep 2011;11(2):128–35.
  11. Accurso A, Bernstein RK, Dahlqvist A, et al. Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal. Nutr Metab (Lond) 2008;5:9.
  12. Tay J, Luscombe-Marsh ND, Thompson CH, et al. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: A randomized trial. Am J Clin Nutr 2015;102(4):780–90.

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 Type 2 diabetes: Goals for optimum management (PDF2MB)

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