10-minute consultation : type 2 diabetes mellitus [2 ed.] 9781905982158, 9781905982073

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The 10-minute consultation: type 2 diabetes mellitus second edition

ISBN: 978-1-905982-15-8

9 781905 982158

The 10-minute consultation:

type 2 diabetes mellitus second edition

Advisory board R Gadsby DW Haslam K Khunti M Kirby M Mead

The 10-minute consultation:

type 2 diabetes mellitus second edition Advisory board Dr Roger Gadsby GP and Associate Clinical Professor Warwick Medical School, University of Warwick, UK Dr David W Haslam GP and Clinical Director of the National Obesity Forum Watton Place Clinic, Watton-at-Stone, UK Professor Kamlesh Khunti Professor of Primary Care Diabetes and Vascular Medicine, Department of Health Sciences University of Leicester, UK Professor Michael Kirby Visiting Professor, Centre for Research in Primary and Community Care, University of Hertfordshire, UK Dr Mike Mead GP, Leicester, UK

Published by Cedilla Publishing Limited PO Box 58871, London SE15 9BE, UK Telephone: +44 (0)7794 485294 www.cedillapublishing.com © 2009, 2010, 2012 Cedilla Publishing Limited All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the written permission of the copyright owner. British Library Cataloguing in Publication Data A catalogue for this book is available from the British Library. ISBN: 978-1-905982-15-8 second edition PDF ebook (978-1-905982-07-3 second print edition) (978-1-905982-04-2 first print edition) Cover image: weight measuring. Gustoimages / Science Photo Library The publisher and authors have made every effort to ensure the accuracy of the information in this book, but cannot accept responsibility for any errors or omissions. No claims or endorsements are made for any drug or compound at present under clinical investigation.

Contents 1. Introduction

1



What is the spectrum of disease?

1



What is the burden of type 2 diabetes mellitus?

3

2. Who and what to test

6



6

Screening and case finding

What issues should the general practitioner (GP) cover during the 10-minute consultation?

9

Target-organ damage and complications of type 2 diabetes mellitus

35



36

Assessment of CV risk

Differential diagnosis: the metabolic syndrome, PCOS and nonalcoholic steatohepatitis (NASH)

37

3. How to manage the person with type 2 diabetes mellitus

39



Who to treat?

39



How to treat?

39



What are the treatment targets?

39



General lifestyle advice

40



Blood glucose levels and type 2 diabetes mellitus

44



Other prophylactic drug therapies

62

What are the benefits of treating co-morbidities/multiple CV risk factors?

62



66

Other co-morbidities: depression

The 10-minute consultation: type 2 diabetes mellitus

4. Person-centred care

67

How to identify the patient’s beliefs about type 2 diabetes mellitus and its complications (their concerns and expectations)?

67



68

What are the patient’s cultural beliefs and practices?

How to recognise nonconcordance with management strategies?

70



72

Are any treatments particularly appropriate?

5. Applying the evidence

74

What are the implications of the international best-practice guidelines for GPs?

74



75

Selected landmark studies

What are the primary care prescribing options for treating to target in type 2 diabetes mellitus: a summary

79



When to refer?

80

6. Review and recall

84

What ongoing patient care, monitoring and follow-up are necessary?

84

What roles do other key healthcare workers have in managing the patient?

86



What is the role of information technology (IT)?

87



What is the role of the expert patient?

88



Monitoring performance and the quality of care

89



Further reading

90

Chapter 1 Introduction What is the spectrum of disease? Diabetes mellitus is a common metabolic disorder characterized by hyperglycaemia and abnormalities of carbohydrate and lipid metabolism.

Impaired glucose regulation (sometimes referred to as ‘prediabetes’) The term ‘impaired glucose regulation’ is used if serial plasma glucose levels are above normal but below the diagnostic threshold for diabetes (p. 27). It can occur if the body either doesn’t use insulin efficiently (insulin resistance) or doesn’t produce enough insulin (insulin deficiency). Unmanaged, diabetes can develop within 10 years in 50% of individuals. However, with therapeutic lifestyle changes (eg, weight loss, eating a lower-fat diet and increasing levels of physical activity), plasma glucose could return to normal or stay below the level of blood glucose used to diagnose diabetes. Impaired glucose regulation is also categorized as ‘impaired fasting glucose’ (IFG) or ‘impaired glucose tolerance’ (IGT), depending on which test is used to identify it.

IFG and IGT • I FG is defined as a fasting plasma glucose level of ≥6.1 to ≤6.9 mmol/L (110–125 mg/dL). • I GT is defined as a fasting plasma glucose level of 30 kg/m2, central obesity can be assumed. Plus any two of the following: • Raised triglyceride concentration >1.7 mmol/L (150 mg/dL) or specific treatment for this lipid abnormality • Reduced HDL cholesterol level 5.6 mmol/L (100 mg/dL) or previously diagnosed type 2 diabetes mellitus. If the fasting glucose level is >5.6 mmol/L (100 mg/dL), an oral glucose tolerance test is strongly recommended, but is not necessary, to diagnose the syndrome Table 1.1 HDL, high-density lipoprotein.

What is the burden of type 2 diabetes mellitus? The IDF estimates that the overall global prevalence of type 2 diabetes mellitus is about 5%, of which only half of the patients are clinically diagnosed. Prevalence of the disease is increasing rapidly (it is epidemic in many developing and newly industrialized countries), primarily a consequence of the increasing prevalence of obesity, particularly in children and adolescents. The consequent rise in the healthcare burden and costs owes not only to the greater number of patients with the disease itself, but also to the effect of long-term vascular complications.

Who is at risk of type 2 diabetes mellitus? The greater the number of the following risk factors an individual has, the greater the probability of development of type 2 diabetes mellitus: • O  besity, particularly central/abdominal obesity (an ‘apple’shaped figure). 3

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

• Advancing age. • Sedentary lifestyle. • Family history. • History of diabetes in pregnancy. • Certain ethnic groups. • Hypertension. • Dyslipidaemia. • IGT.

What are the long-term complications of type 2 diabetes mellitus? The complications of type 2 diabetes mellitus can be classified as follows: • Acute complications – ketoacidosis and coma. • C  hronic complications – microvascular (eg, retinopathy, nephropathy, neuropathy and foot problems) or macrovascular (eg, CV [coronary and cerebrovascular] disease, peripheral vascular disease [PVD] or heart failure). Microvascular diseases are specific to diabetes mellitus, but macrovascular disease commonly seen in diabetes mellitus is broadly the same as that seen in people without diabetes mellitus; however, the difference in diabetes mellitus is the increased risk. In fact, the increase in risk starts with IGT, below the level of blood glucose used to diagnose diabetes mellitus. Complications result in increased disability, reduced life expectancy and enormous health costs; about 80% of people with type 2 diabetes mellitus will die from CV disease. Microalbuminuria (in which the urine contains traces of protein undetected by a standard dipstick test; urinary albumin concentration of ≥20 mg/L or an albumin:creatinine ratio [ACR] of ≥2.5 mg/mmol in men or ≥3.5 mg/mmol in women) is a predictor of the development of microvascular and macrovascular (renal and CV) disease. The finding of microalbuminuria indicates the need for assessment of microvascular complications and tighter control of CV risk factors (eg, adverse lipid profile, 4

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Introduction

hypertension and smoking status). In people with type 2 diabetes mellitus, proteinuria (urinary albumin concentration of ≥200 mg/L or an ACR of ≥30 mg/mmol) might occur early, possibly at diagnosis, owing to the advanced age, insidious onset and co-existent vascular disease. Microalbuminuria precedes overt proteinuria, which is progressive, leading to renal failure. People with type 2 diabetes mellitus should be screened annually for microalbuminuria.

Who is at risk of diabetes-related complications? All people with type 2 diabetes mellitus are at risk of complications, although the risk is greater if the disease is not managed adequately or any of the following factors are present: • • • • • • • • • •

High blood glucose levels. Hypertension. Advancing age. Low high-density lipoprotein (HDL). High total cholesterol levels. Male gender. Positive smoking status. Family history of kidney disease. South Asian or African–Caribbean origin. High levels of protein in the urine.

5

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Chapter 2 Who and what to test Screening and case finding What is screening? General population screening uses questionnaires and/or a random blood glucose test to identify patients who might have type 2 diabetes mellitus and exclude those who do not. Screening is performed by trained practice nurses during the new-patient registration check or screening clinics (eg, hypertension, weight-management or wellwomen clinics). It should be noted that the benefits of population-based screening for type 2 diabetes mellitus in primary care are unproven.

Why is screening important? People with type 2 diabetes mellitus are often asymptomatic and screening patients at high risk of developing type 2 diabetes mellitus promotes early diagnosis, before complications develop. If the aim is to reduce the prevalence of CV disease, consider screening for other abnormalities of glucose metabolism (eg, IGT and the metabolic syndrome) in addition to type 2 diabetes mellitus.

Who to screen? Screening for hyperglycaemia, dyslipidaemia, hypertension and obesity should be performed as part of a multiple risk-factor approach to primary and secondary prevention of CV disease (of which type 2 diabetes mellitus is an important subgroup) and is helpful to identify those who might benefit from therapeutic lifestyle changes and/or treatment. In the UK, the Department of Health has recently introduced a free National Health Service (NHS) Health Check offer for people without established CV disease aged between 40 and 74, to assess risk of heart disease, stroke, kidney disease and type 2 diabetes mellitus and provide support in the management or reduction of risk by means of person6

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

centred advice. The check comprises questions and measurements to record age, height, weight, drug history, family history, smoking status, blood pressure (BP), lipid profile and glucose level. Risk assessment for gestational diabetes mellitus should occur at the first prenatal visit. Screening should take place between 24 and 28 weeks gestation or earlier if there is clinical suspicion. Women with gestational diabetes should undergo lifelong screening for type 2 diabetes mellitus. If type 2 diabetes mellitus is diagnosed, further screening is necessary for its complications, especially eye, renal and foot screening (p. 35). Screening should be part of a co-ordinated vascular disease control programme, including CHD, stroke, renal disease, PVD and type 2 diabetes mellitus.

Who not to screen? Often, screening all patients is not feasible (eg, time constraints and cost) and active case finding is recommended instead. To date, there is no evidence to support general population screening for type 2 diabetes mellitus.

What is case finding? Case finding identifies probands, according to the level of risk, for targeted screening/diagnostic testing (a fasting plasma glucose and/ or an OGTT). Several approaches can be used, for example: • S  creening can be conducted using patient self-assessment tools, such as the FINRISC questionnaire (Figure 2.1), although these have not been validated in UK multi-ethnic populations. • S  creening computerized patient records according to weighting for age, sex, family history, smoking status, obesity and antihypertensive or steroid treatment.

What is the value of case finding? Opportunistic case finding is more cost-effective than screening and based on the presence of risk factors (p. 3) and symptoms (p. 11). 7

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

Figure 2.1 p, points. FINRISC Test designed by Professor Jaakko Tuomilehto, Department of Public Health, University of Helsinki, and Jaana Lindström, MFS, National Public Health Institute, Finland. 8

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

Which patient groups should case-finding programmes focus on? • Those with known IGT or IFG. • T  hose with a body-mass index (BMI) of >30 or 25–30 who have a sedentary lifestyle or high waist circumference. • Patients aged >50 years. • Certain ethnic groups (eg, African–Caribbean or South Asian). • A history of diabetes in a first-degree relative (parent or sibling). • P  atients with other CV risk factors (eg, hypertension, dyslipidaemia or positive smoking status). • T  hose with a history of CV disease or established ischaemic heart disease (IHD), cerebrovascular disease, PVD (or problems with blood circulation, including myocardial ischaemia and stroke) or hypertension or present with an acute CV event. • Women with a history of gestational diabetes. • W  omen with polycystic ovary syndrome (PCOS) who are obese (BMI of >30).

What issues should the general practitioner (GP) cover during the 10-minute consultation? The clinical reality is a series of ‘10-minute’ consultations carried out by different health professionals, with supervision by the GP or in a diabetes clinic, which might take the following general format: •

Initial consultation: • Presentation of disease (cardinal symptoms; p. 11). • History-taking (p. 10). • Physical examination (p. 15). • Urinalysis ‘stix’ test (p. 33). • Assessment of risk factors for vascular disease (p. 35). • Blood glucose test (p. 26). • Provisional diagnosis.

• Laboratory investigations: 9

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus



• Renal function (serum creatinine and estimated glomerular filtration rate [eGFR]; p. 30).



• Liver function.



• Test for microalbuminuria (p. 34).



• Fasting blood test (full lipid profile and OGTT; p. 26 and 32).

• O  n receipt of test results, a further consultation to cover the following:

• Confirmation of diagnosis.



• Patient education (p. 40 and 67).



• Start therapy (p. 45).



• Referral for eye screening.



• Gestational diabetes consultation for pregnant women.

• A  ll newly presenting patients should be added to the diabetes register and included on the call–recall system (p. 84 and 88). • Annual follow-up consultation:

• Review of therapy and treatment plan, including selfmonitored results (p. 70).



• Appropriate referral for specialist treatment or patient education, as necessary (p. 67 and 82).

Taking a patient history What are your first impressions of the patient? • W  hat is the patient’s general appearance like? For example, weight, pallor, sweating or impaired consciousness. • Cushing’s syndrome. • D  oes the patient’s breath smell of ketones (‘fruity’; rare in type 2 diabetes mellitus)? • D  oes the patient present with facial clues to dyslipidaemia: xanthomas, corneal arcus or xanthelasma? • N  icotine/tar staining on fingers or teeth indicates that the patient is a smoker. • A  re there any other clues regarding the patient history of illness (eg, Kaussmaul breathing/deep sighing)? 10

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

• W  hat is the patient’s ethnic origin? People from certain ethnic communities have up to sixfold greater risk of development of type 2 diabetes mellitus. How should the assessment interview be structured? • E  ncourage the patient to tell you what has happened to bring them to the surgery in their own words. • U  se open questions to facilitate the patient’s history in their own words (eg, about general health status and symptoms). • U  se closed questions to clarify the details (eg, about occupation, smoking status and medical or patient’s terminology). • A  sk sensitive questions in an objective, nonjudgemental manner to uncover symptoms that the patient might feel uncomfortable about (eg, erectile dysfunction). • Focus on the symptoms that are most relevant. • S  ummarize your understanding of the problem for the patient (focusing on the most troublesome symptoms). • Describe the next steps to the patient. What are the cardinal symptoms in each of the major systems? Active discussion during the interview can identify the relevant organ system(s) responsible for the patient’s symptoms.

The principal symptoms of type 2 diabetes mellitus are as follows:

• Excessive thirst (polydipsia) and urine volume. • Men might report erectile dysfunction. • Recurrent infections. • Unexplained loss of weight. • Extreme tiredness and, in severe cases, drowsiness and coma. • Blurred or deteriorating vision. • Slow wound healing. • Genital itching and/or frequent episodes of thrush. • Foot infections. Role of the GP • I f symptoms suggest type 2 diabetes mellitus, the diagnosis can be confirmed by a blood test (p. 27). 11

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

Taking a drug history • Ask the patient if they are taking any medications and check their record of prescriptions. • Drugs for CV disease (post-myocardial infarction [MI] or angina). • Look for drugs that might be associated with an increased risk of diabetes mellitus (eg, steroids, diuretics and beta-blockers). • Drugs prescribed for the risk factors that cluster in the metabolic syndrome (eg, antihypertensive, lipid-lowering and anti-obesity medications). Does the patient smoke? • Determine smoking status (ie, smoker or nonsmoker). • If the patient is a current smoker or exsmoker, quantify the number of cigarettes smoked daily and the number of smoking years (‘pack years’): 20 cigarettes = 1 packet Number of number of cigarettes smoked daily number of = x pack years 20 smoking years Classification of smoking status and risk of CV disease • Smoking is the greatest single cause of illness and premature death in the UK; smoking tobacco is associated with increased risk of CV disease, including arteriosclerosis, CHD, stroke and PVD. • There is a clear dose-dependent relationship between the number of cigarettes smoked and CV disease risk. • Smoking synergistically interacts with other CV risk factors (including dysglycaemia) to increase the cumulative CV risk. • Vascular complications of type 2 diabetes mellitus are more common in smokers. Role of the GP • If possible, assess the smoking status of all patients at least once yearly. • Record the smoking status of people with type 2 diabetes mellitus in the patient notes and whether advice on smoking cessation was given or referral to a specialist was made. 12

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

Interventions to stop smoking Ask whether patients smoke routinely Assess the patient’s degree of addiction and readiness to stop smoking Advise all smokers to quit Assist smokers in quitting Arrange follow-up Table 2.1

• U  se clinical judgement in estimating CV disease risk in exsmokers according to the patient’s total exposure (number of pack years). • For smokers, a discussion of smoking habits and setting a specific date for cessation should be included in every consultation. • Effective interventions to help patients stop smoking are referred to as the five ‘A’s (Table 2.1). Does the patient consume alcohol regularly? • One unit of alcohol is equivalent to approximately 80 mL (a small glass) of wine/sherry, 250 mL (a half-pint) of standardstrength beer or 30–50 mL (one measure) of spirits. • R  ecommended consumption is lower for women than men: 25 (ie, overweight or obese) should be encouraged to lose weight. 17

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

Figure 2.2 BMI, body-mass index. 18

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

Classification of overweight and obesity in children The Child Growth Foundation BMI percentile chart should be used to identify overweight and obese children: Overweight: BMI ≥91st centile Obese: BMI ≥98th centile Figure 2.2 Continued. BMI, body-mass index.

• Investigate the underlying cause of sudden weight loss. • P  atients with a BMI 200 mmHg and diastolic BP >130 mmHg) in association with bilateral retinal haemorrhage and exudates, with or without papilloedema. Accelerated hypertension is diagnosed if BP has increased rapidly and grade 3 or 4 retinopathy is present. It is a medical emergency. • ‘ Postural hypotension’ is defined as a fall in BP of ≥20 mmHg on standing. 24

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

Figure 2.4 BP, blood pressure.

• M  any patients with peripheral arterial disease (PAD) have asymptomatic subclavian artery disease. A difference of up to 10 mmHg in systolic BP between the patient’s arms is normal. If the difference is >10 mmHg, the higher value indicates the true central pressure. Role of the GP • T  he minimum BP for a diagnosis of hypertension is a systolic BP of 140 mmHg and/or diastolic BP of 90 mmHg; however, systolic BP of 120–139 mmHg or diastolic BP of 80–89 mmHg should be considered prehypertensive and requires healthpromoting lifestyle changes to prevent CV disease. • K  eep a register of patients with hypertension and people with type 2 diabetes mellitus who have a BP >145/85 mmHg. • A  nyone diagnosed with hypertension should automatically be screened for CV risk factors, some of which might be other components of the metabolic syndrome. 25

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

• L  ook for clues to the underlying cause of secondary hypertension in the patient history or physical examination (eg, obesity, excessive alcohol intake or pregnancy). • For patients with established type 2 diabetes mellitus or atherosclerotic disease, assess BP in relation to treatment targets. If BP is ≥130/80 mmHg, consider patients for further evaluation of target-organ damage. • Monitor BP regularly until the target level is achieved and maintained; then measure at least annually. • Refer patients with postural hypertension for further evaluation; it might indicate diabetic autonomic neuropathy. .

When to perform a blood test Blood glucose testing in the surgery • H  yperglycaemia is a major risk factor for CV disease; type 2 diabetes mellitus increases the relative risk of CV disease between twofold and fourfold, with a higher risk in diabetic men than diabetic women. A person with type 2 diabetes mellitus has the same risk of MI as someone who has had a previous MI. • Impaired glucose regulation (IGT and IFG) is a risk factor for type 2 diabetes mellitus and CV disease; IGT increases the risk of CV disease about 1.5-fold. • Hyperglycaemia synergistically interacts with other CV risk factors, particularly smoking, dyslipidaemia and hypertension, to increase cumulative CV risk. • Abnormalities of glucose tolerance are commonly seen in patients with the metabolic syndrome. • All adults >40 years should have a random (nonfasting) plasma glucose test as part of an opportunistic CV assessment in primary care but questionnaires and the presence of risk factors can be used to identify patients for targeted screening (p. 7). • There are several tests available for measuring blood glucose levels (Table 2.7); fasting plasma glucose is the main test used to diagnose diabetes mellitus in asymptomatic patients, but an OGTT is used to diagnose IGT or early diabetes mellitus 26

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Average blood glucose level over the preceding 3 months

HbA1c 6.5%

Fasting = >7.0 mmol/L (125 mg/dL) 2 h after glucose load = >11.1 mmol/L (200 mg/dL)

≥7.0 mmol/L (125 mg/dL)

≥6.1 to ≤11.0 mmol/L >11.1 mmol/L (110–200 mg/dL) (200 mg/dL)

Impaired glucose regulation

Table 2.7 The plasma glucose sample must be clearly defined as ‘fasting’ or ‘random’. ‘Fasting’ is defined as no consumption of food or beverage other than water for at least 8 h before the test. Diabetes mellitus is diagnosed after two blood tests on separate occasions, unless the patient is symptomatic. HbA1c, glycosylated haemoglobin; IFG, impaired fasting glycaemia; IGT, impaired glucose tolerance.

Routine monitoring of diabetic control

Patients who have a fasting plasma glucose level indicating impaired glucose regulation

Fasting plasma glucose level and plasma glucose level after a glucose load

Oral glucose tolerance Fasting = 7.0 mmol / L (125 mg/dL) or plasma glucose concentration of >11.1 mmol/L (200 mg/dL) 2 h after a glucose load (eg, 75 g of glucose in 250 mL of water or 375 mL of Lucozade Original) in an OGTT. • The HbA1c is between 3% and 6% in a nondiabetic patient; an HbA1c value >6% indicates hyperglycaemia. A 1% increase Good clinical practice: oral glucose tolerance test • The patient should fast and not exercise during the 12 h before the test • Take a fasting venous blood sample • The patient should be given a drink containing 75 g of glucose in 250 mL of water • After 2 h, take another venous blood sample • Label both bottles appropriately Table 2.8 28

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

in the HbA1c is associated with greater rates of microvascular and macrovascular diseases (complications of type 2 diabetes mellitus). Role of the GP • B  roadening the clinical focus to include interventions for patients with IFG and IGT increases the scope and yield for CV disease prevention; the majority of fatal CV events occur in patients with an HbA1c of >6% in the absence of diabetes mellitus. • C  onsider patients with hyperglycaemia for further evaluation of other major risk factors (eg, BP and lipids), and intervention, to prevent development of diabetes mellitus and CV disease. • P  atients with IFG and IGT are at increased risk of CV disease and the targets for treatment of their lipid levels should be the same as for patients with diabetes mellitus. • F  or asymptomatic patients with no previous history of diabetes mellitus or CV disease, the plasma glucose level should be considered in the context of total CV risk estimated using a CV risk prediction calculator (eg, the UKPDS risk engine; p. 92). • Hyperglycaemia should be carefully controlled in people with type 2 diabetes mellitus. • Consider testing HbA1c before each clinic visit (aim for an HbA1c between 6.5% and 7.5%); it should be measured at least every 6 months. • Patients with a fasting plasma glucose level of >25 mmol/L (450 mg/dL) should be referred for specialist management. • Keep a register of patients aged >17 years with diabetes that specifies whether the person has type 1 or 2 diabetes mellitus. Treatments that people with type 2 diabetes mellitus receive can be recorded by use of Read codes. • Patients with gestational diabetes should be recorded on a separate register of people with IGT. • Keep a record of people who have an HbA1c of >7.5%. • Practices should review their prevalence figures (%) against other local practices or a published Primary Care Trust (PCT) average. 29

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

Serum urea, creatinine and electrolytes • Testing indicates whether renal function is impaired. • Renal complications are common in type 2 diabetes mellitus. • Diabetic nephropathy is characterized by hypertension, albuminuria and progressive renal insufficiency and is the primary cause of chronic renal failure in many countries. • Co-existing hypertension accelerates renal failure; hyperglycaemia, dyslipidaemia, obesity and smoking are risk factors for the progression of nephropathy. • The local laboratory provides ranges on paper and as electronic results. Classification of renal function and risk of CV disease • Renal function should be assessed according to the serum creatinine level and eGFR. Measure serum creatinine annually and calculate the eGFR. • Renal function can fall to a GFR of 50 mL/min before serum creatinine rises above its normal range (50–110 µmol/L [0.6 – 1.2 mg/mL]). • An increase in the creatinine level is an indicator of the severity of renal dysfunction and suggests target-organ damage. • Creatinine clearance decreases with increasing age so lower values might be normal in the elderly. Role of the GP • V  alues outside normal ranges are abnormal and require further investigation. • S  erial measurements can be used to monitor the patient’s progress. • A  ll patients with impaired renal function should be managed in accordance with standard protocols (Figure 2.5) and referred to a specialist, as necessary. • Keep a register of patients with renal disease. • B  P control in people with type 2 diabetes mellitus significantly reduces the progression of kidney disease; use an angiotensinconverting enzyme (ACE) inhibitor or angiotensin II receptor antagonist to block the renin–angiotensin system. 30

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

Figure 2.5 BP, blood pressure; GFR, glomerular filtration rate; MSU, midstream urine. Full details are available at http://www.kidney.org/professionals/doqi/ kdoqi/p5_lab_g4.htm (accessed 02 August 2006). 31

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

• E  xamine the patient for signs of other vascular complications of type 2 diabetes mellitus. Measuring the lipid profile in the surgery • A  ll people with type 2 diabetes mellitus should have a fasting lipid profile measurement for total LDL and HDL cholesterol levels and triglycerides (Table 2.9). • A  bnormalities of lipid metabolism are common in type 2 diabetes mellitus; diabetes mellitus can also affect the lipid profile if it is poorly controlled. • D  iabetes mellitus is a significant contributor to absolute CV risk prediction: hyperglycaemia interacts synergistically with other CV risk factors, including dyslipidaemia, hypertension and smoking, to increase cumulative CV risk. • L  ipid abnormalities are important predictors of CVD in people with type 2 diabetes mellitus. Classification of lipid levels and risk of CV disease • Lipid levels outside the normal ranges. • ‘ Diabetic dyslipidaemia’ is characterized by elevated triglycerides and decreased HDL levels and raised levels of atherogenic small, dense LDL cholesterol. Good clinical practice: measurement of serum cholesterol levels • The patient should be asked to fast and not to exercise in the 12–14 h before the test, usually from 10pm the previous evening • The patient should be seated for 5–10 min before the venous blood sample is drawn • Take blood from an uncuffed arm • Repeat the test after two months if the test results are abnormal • Delay testing for 3 weeks following a minor illness • Delay testing for 2–3 months following a major illness Table 2.9 32

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

• A  bdominally obese people (p. 20) have an atherogenic lipid profile (the ‘hypertriglyceridaemic waist’) associated with increased risk of CV disease. Role of the GP • A  im to differentially diagnose primary and secondary hyperlipidaemias because the former has a higher risk of CV disease. Consider the need for further investigations. • T  he majority of patients with abnormal lipid levels can be managed in primary care; most people with type 2 diabetes mellitus should receive a statin. • L  ow HDL cholesterol and elevated triglyceride levels might require additional treatment once the total and LDL cholesterol targets are achieved. • E  stimate total CV risk and treat individual risk factors using the UKPDS risk engine (p. 92), as required. • M  onitor lipids regularly until the target level is achieved; then measure at least annually. • P  regnancy can affect the lipid profile and might affect the management strategy. • K  eep a register of people with dyslipidaemia and those with diabetes mellitus whose total cholesterol level is >5 mmol/L (190 mg/dL).

Urinalysis • D  ipstick analysis (Table 2.10) can indicate the presence of glucose, blood, protein and ketones in the urine. • T  aking an early morning urine specimen is recommended to avoid postural proteinuria in patients >30 years of age. • R  isk factors for microalbuminuria include poor glycaemic control, hypertension and smoking. • D  etection of microalbuminuria is important because in people with type 2 diabetes mellitus it indicates increased risk of mortality from MI or stroke. 33

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus

Good clinical practice: dipstick analysis • Use an early morning urine specimen 30 mg/mol. Role of the GP • H  igh levels of glycosuria are detected in type 2 diabetes mellitus. 34

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

Who and what to test

• I f blood is detected in the urine, red blood cells should be looked for in a midstream urine sample. Investigate the underlying cause of haematuria, particularly bladder neoplasm. If no cause is found, refer the patient to a specialist for further evaluation. • Exclude causes of transient proteinuria. • R  esistant proteinuria is defined as at least two positive tests for proteinuria 1 to 2 weeks apart. Refer patients with significant proteinuria (>100 mg/mmol or >50 mg/mmol with other symptoms of renal disease) to a nephrologist for further investigation. • M  icroalbuminuria precedes persistent albuminuria in people with type 2 diabetes; antihypertensive therapy can slow this progression. The finding of microalbuminuria in people with type 2 diabetes mellitus is an indication for antihypertensive therapy, especially with inhibitors of the renin–angiotensin system, irrespective of the BP value. • P  ositive microalbuminuria/proteinuria should be managed by optimizing BP, lipid and glucose control. • A  ny patient with ketones in their urine should be referred for specialist management and urgent hospital admission is required for patients with signs of diabetic ketoacidosis.

Target-organ damage and complications of type 2 diabetes mellitus • T  he risk of vascular disease is directly related to the duration and severity of sustained hyperglycaemia. • V  ascular complications can cause substantial morbidity and disability: • Blindness relating to hypertensive or diabetic retinopathy. • Difficulty walking, chronic ulceration of the legs and feet, bladder and bowel dysfunction relating to autonomic neuropathy. • Renal artery stenosis, angina, heart failure, intermittent claudication and gangrene relating to atherosclerosis. 35

This chapter is from Gadbsy, R et al. (2012) The 10-minute consultation: type 2 diabetes mellitus second edition. London: Cedilla Publishing Ltd. Copyright © 2012 Cedilla Publishing Ltd. All Rights Reserved. To order a print copy of the book, please email [email protected].

The 10-minute consultation: type 2 diabetes mellitus



• Renal failure relating to diabetic nephropathy.

• T  arget-organ damage should be assessed by the patient history and physical examination: • BP. • General appearance (eg, alertness and body weight). • Retinal examination. • Heart. • Lungs. • Hands and feet. • Neurological examination.

Role of the GP • T  reating hyperglycaemia to current best-practice recommendations is important to reduce microvascular complications (retinopathy, nephropathy and neuropathy) but is less effective in reducing the risk of CV disease in people with longstanding type 2 diabetes mellitus. • C  ontrol of lipid levels and BP is also crucial to prevention of CV disease, in addition to good blood glucose control. Antihypertensive therapy can reduce both microvascular and macrovascular complications, whereas lipid-lowering therapy is cardioprotective. • Treatment with ACE inhibitors and statins is recommended. • Consider dialysis in patients with end-stage renal failure. • P  atients with diabetes mellitus and/or hypertension who have a raised serum creatinine level (>150 µmol/L; GFR