WHO/NMH/MNC/03.1
`
`Original: English
`
`Screening for Type 2 Diabetes
`
`Report of a World Health Organization and
`International Diabetes Federation meeting
`
`
`
`World Health Organization
`
`Department of Noncommunicable Disease Management
`
`Geneva
`
`Boehringer Ex. 2003
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`IPR2016-01564
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`WHO/NMH/MNC/03.1
`
`Original: English
`
`Screening for Type 2 Diabetes
`
`Report of a World Health Organization and
`International Diabetes Federation meeting
`
`
`
`World Health Organization
`
`Department of Noncommunicable Disease Management
`
`Geneva
`
`Boehringer Ex. 2003
`Mylan v. Boehringer Ingelheim
`IPR2016-01564
`Page 2
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`

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`Screening for Type 2 Diabetes
`
`© World Health Organization 2003
`
`All rights reserved. Publications of the World Health Organization can be
`obtained from Marketing and Dissemination, World Health Organization, 20
`Avenue Appia, 1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +41
`22 791 4857; email: bookorders@who.int). Requests for permission to
`reproduce or translate WHO publications – whether for sale or for
`noncommercial distribution – should be addressed to Publications, at the
`above address (fax: +41 22 791 4806; email: permissions@who.int).
`
`The World Health Organization does not warrant that the information
`contained in this publication is complete and correct and shall not be liable for
`any damages incurred as a result of its use.
`
`This publication contains the collective views of an international group of
`experts and does not necessarily represent the decisions or the stated policy of
`the World Health Organization.
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`Contents
`
`1
`2
`
`3
`4
`5
`
`Introduction
`Background....................................................................................................................1
`2.1
`Diabetes and its consequences..........................................................................1
`2.2
`Screening for type 2 diabetes – why WHO and IDF convened this meeting...2
`2.3
`Effects of screening on individuals, health systems and society......................3
`2.4
`Screening and prevention - the links ...............................................................4
`Aims of the meeting .....................................................................................................5
`Terminology – what is screening ..........................................................................5
`Evaluating screening tests and programmes.................................................................6
`5.1
`General issues..................................................................................................6
`5.2
`Issues specific to diabetes................................................................................8
`5.2.1 Range of available tests......................................................................8
`5.2.2 Evaluating screening procedures........................................................8
`5.2.3
`Performance indicators.......................................................................9
`5.2.4
`Performance of screening tests for type 2 diabetes............................9
`5.2.4.1 Questionnaires.......................................................................9
`5.2.4.2 Urine glucose.......................................................................10
`5.2.4.3 Blood glucose......................................................................11
`5.2.4.4 Glycated haemoglobin.........................................................13
`5.2.4.5 Combinations of tests..........................................................13
`5.2.4.6 Public response to screening for type 2 diabetes.................14
`5.2.4.7 Frequency of testing............................................................15
`5.2.5 Assessing the risk of future development of type 2 diabetes...........15
`The current evidence base..........................................................................................16
`6.1
`Evidence relating to the efficacy of early detection......................................16
`6.2
`Evidence relating to economic aspects of early detection.............................18
`6.3
`Evidence relating to the psycho-social effects of early detection.................20
`Formulating policies about screening for type 2 diabetes..........................................21
`7.1
`The aims and objectives of a screening policy.............................................21
`7.2
`Epidemiological considerations....................................................................21
`7.3
`Considerations of health system capacity.....................................................21
`7.4
`Economic considerations..............................................................................22
`7.5
`The choice of a test or tests...........................................................................22
`7.6
`Competing priorities ....................................................................................23
`7.7
`Ethical and political considerations..............................................................23
`Widening the evidence base .....................................................................................23
`8.1
`The need for evidence from randomized controlled trials............................23
`8.2
`The need for observational studies...............................................................24
`8.3
`The need for economic evidence..................................................................25
`8.4
`The use of modelling studies........................................................................25
`8.5
`The need for evidence on the psycho-social effects of early detection........25
`Implementing policies about screening for type 2 diabetes......................................27
`Conclusions and recommendations...........................................................................29
`10.1 Conclusions................................................................................................ 29
`Recommendations...................................................................................... 30
`10.2
`Annex 1
`List of participants of the WHO/IDF meeting.............................................32
`Annex 2
`Acknowledgements......................................................................................33
`Tables and figures..................................................................................................................35
`References..............................................................................................................................41
`
`8
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`6
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`7
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`9
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`1
`
`Introduction
`
`Over the past decade it has been obvious that the prevalence of type 2 diabetes
`is increasing rapidly. Unless appropriate action is taken, it is predicted that
`there will be at least 350 million people in the world with type 2 diabetes by
`the year 2030. This is double the current number. Equally alarming and less
`well known is the fact that, of these people, only around one half are known to
`have the condition. This has been shown repeatedly in epidemiological
`surveys. An added concern is that half of those who do present with type 2
`diabetes clinically already have signs of the complications of the disorder.
`
`It has not yet been proven that earlier detection will improve the outcome of
`people with type 2 diabetes, but it seems logical to suggest that it may help.
`The implication of this is that people need to be screened for diabetes on a
`regular basis. There is still uncertainty whether this should be done on a
`population-wide basis or just for those people who can be shown to have a
`high risk. It is also uncertain at what age the screening programmes should be
`introduced, if at all.
`
`This report focuses solely on screening for type 2 diabetes in non-pregnant
`adults. It does not consider screening for type 1 diabetes, screening for type 2
`diabetes in children, nor screening for gestational diabetes. This is not to
`imply that these topics are unimportant. On the contrary, they are each
`important enough to require detailed consideration in their own right.
`
`It is clear to both the World Health Organization (WHO) and the International
`Diabetes Federation (IDF) that guidance is needed for both our member
`countries and member associations. Because of this the WHO and the IDF
`have come together to produce this document, which, though it poses as many
`questions as it answers, is a clear and logical start to a very serious debate.
`We hope that the report will provide guidance and provoke discussion and
`new studies and in the long term will be of benefit to the many people in the
`world with and at risk of type 2 diabetes.
`
`Dr Derek Yach
`Executive Director
`Noncommunicable Diseases
`and Mental Health Cluster
`World Health Organization
`Geneva
`
`Professor Sir George Alberti
`President
`International Diabetes Federation
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`2
`
`Background
`
`2.1
`
`Diabetes and its consequences
`
`Diabetes mellitus is a metabolic disorder characterized by chronic
`hyperglycaemia with disturbances of carbohydrate, fat and protein
`metabolism resulting from defects in insulin secretion, insulin action,
`or both1. The current diagnostic criteria are shown in Table 1 In
`summary, diabetes is diagnosed if the (venous) fasting plasma glucose
`(FPG) value is >= 7.0 mmol l-1 (126 mg dl-1), or if the casual plasma
`glucose value is >= 11.1 mmol l-1 (200 mg dl-1), or if the plasma
`glucose value 2 hours after a 75g oral load of glucose >= 11.1 mmol l-1
`(200 mg dl-1). In asymptomatic subjects, performing the test on one
`occasion is not enough to establish the diagnosis (i.e. basis to treat
`diabetes). This must be confirmed by carrying out at least one further
`test on a subsequent day.
`
`Impaired glucose tolerance (IGT) and impaired fasting glycaemia
`(IFG) are risk categories for the future development of diabetes and
`cardiovascular disease (CVD). An individual falling into the IFG
`category on the fasting result may also have IGT on the 2-h value or,
`indeed, diabetes. If an individual falls into two different categories, the
`more severe one applies.
`
`The classification of diabetes is based on aetiological types1. Type 1
`indicates the processes of beta-cell destruction that may ultimately lead
`to diabetes in which insulin is required for survival. Type 2 diabetes is
`characterized by disorders of insulin action and /or insulin secretion.
`The third category, "other specific types of diabetes," includes diabetes
`caused by a specific and identified underlying defect, such as genetic
`defects or diseases of the exocrine pancreas.
`
`The latest WHO Global Burden of Disease estimates the worldwide
`burden of diabetes in adults to be around 173 million in the year 2002
`3. Around two thirds of these live in developing countries. Diabetes is
`no longer a condition of developed, ‘industrialised’ or ‘Western’
`countries. Global estimates of the burden of IFG and IGT are not
`available, but the number of people with IGT is likely to be even
`greater than the number with diabetes4,3. IGT and IFG are now
`sometimes referred to as ‘pre-diabetes’ (a term not unanimously
`supported by those attending this meeting since diabetes will not
`necessarily develop in those with IGT or IFG).
`
`The diabetes epidemic is accelerating in the developing world, with an
`increasing proportion of affected people in younger age groups. Recent
`reports describe type 2 diabetes being diagnosed in children and
`adolescents5,6,7. This is likely to increase further the burden of chronic
`diabetic complications worldwide.
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`Most of the consequences of diabetes result from its macrovascular and
`microvascular complications. (Some describe a third category –
`‘neuropathic’, whereas others classify the diabetic neuropathies as
`microvascular complications.) The age-adjusted mortality, mostly due
`to coronary heart disease (CHD) in many but not all populations, is 2-4
`times higher than in the non-diabetic population8, and people with
`diabetes have a 2-fold increased risk of stroke9. Diabetes is the leading
`cause of end stage renal failure in many populations in both developed
`and developing countries10. Lower extremity amputations are at least
`10 times more common in people with diabetes than in non-diabetic
`individuals in developed countries11, and more than half of all non-
`traumatic lower limb amputations are due to diabetes. In developed
`countries, diabetes is one of the leading causes of visual impairment
`and blindness12,13.
`
`People with diabetes require at least 2-3 times the health care resources
`of people who do not have diabetes, and diabetes care accounts for up
`to 15% of national healthcare budgets14,15.
`
`2.2
`
`Screening for type 2 diabetes – why WHO and IDF convened this
`meeting
`
`The main reasons for the current interest in screening for type 2
`diabetes and the reasons why WHO and IDF convened this meeting
`are:
`
`•
`
`that there is a long, latent, asymptomatic period in which the
`condition can be detected16,17;
`
`• a substantial proportion of people with type 2 diabetes are
`undiagnosed (Table 2);
`
`• a substantial proportion of newly referred cases of type 2 diabetes
`already have evidence of the micro-vascular complications of
`diabetes18;
`
`•
`
`•
`
`the rising prevalence19 of type 2 diabetes world-wide;
`
`immediate effects and
`the
`the seriousness of
`complications of type 2 diabetes;
`
`long-term
`
`• evidence supporting the efficacy of intensive blood glucose
`control20,21 blood pressure control22 and blood lipid control23,24 , 25,26
`in type 2 diabetes and
`
`• accumulating
`hypertension,
`of
`treatment
`that
`evidence
`dyslipidaemia (for example lowering LDL cholesterol23,24) can
`prevent cardiovascular disease in people with type 2 diabetes.
`
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`•
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`increasing pressure from professional organisations, lay groups and
`from some of the member associations of IDF to institute screening
`for type 2 diabetes if only to further highlight the increasing
`prevalence and public health importance of the condition.
`
`requests from national and regional health authorities and individual health care
`professionals for guidance as to what should be their policies for screening for type 2
`diabetes.
`
`2.3
`
`Effects of screening on individuals, health systems and society
`
`Policies and practices for screening for type 2 diabetes have profound
`implications for individuals, health systems and society as a whole.
`Implications for individuals include:
`•
`
`the time and other resources necessary to undergo the screening
`test (or tests) and any subsequent diagnostic test (or tests);
`
`•
`
`•
`
`the psychological and social effects of the results whether the
`screening test proves ‘positive’ or ‘negative’ and whether or not the
`diagnosis of type 2 diabetes is subsequently made and
`
`the adverse effects and costs of earlier treatment of type 2 diabetes
`or of any preventive measures instituted as a result of the individual
`being found to have diabetes. These may include occupational
`discrimination and/or increased costs or difficulty in obtaining
`insurance.
`
`The effects on the health system and society as a whole are:
`
`•
`
`•
`
`•
`
`the costs and other implications (especially in primary care and
`support services such as clinical biochemistry) of carrying out the
`screening test (or tests) and the necessary confirmatory test (or
`tests);
`
`the additional costs of the earlier treatment of those found to have
`diabetes or
`to be at high risk of developing diabetes or
`cardiovascular disease in the future and
`
`the implications of false negative and false positive results which
`are inevitable given that any initial test will be a screening test and
`not a full diagnostic test (except in the case of an OGTT with
`markedly abnormal values).
`
`• any loss of production as a result of the earlier diagnosis of the
`condition (from absence from work or reduced job opportunities,
`for example).
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`The potential benefits of early detection of type 2 diabetes are:
`
`• enhanced length and/or quality of life which might result from a
`reduction in the severity and frequency of the immediate effects of
`diabetes or the prevention or delay of its long-term complications.
`
`• Any saving or redistribution of health care resources which might
`be possible as a result of reduced levels of care required for
`diabetes complications (reduced hospital admissions and lengths of
`stay etc.).
`
`2.4
`
`Screening and prevention - the links
`
`Any programme aimed at the early identification of type 2 diabetes
`through screening will also identify individuals with IGT and/or IFG.
`Thus any policy, whether related to public health or day-to-day clinical
`practice must specify what should be done when these conditions are
`identified.
`
`The prognostic significance of IGT and, to an extent IFG, is being
`clarified27. Also, evidence concerning the effect of interventions in
`IGT is now available. In particular, interventions aimed at weight
`reduction and increased physical activity and the use of some
`pharmacological agents have been shown to be effective in reducing or
`delaying the transition to diabetes in those with IGT.
`
`In general, lifestyle interventions appear to be more effective than
`medications28 and the most important, recent trials published in peer
`reviewed journals are summarised in Table 3.
`
`The Diabetes Prevention Programme (DPP) Research Group evaluated
`the cost-effectiveness of the interventions used in their trial29. Life-
`style intervention and metformin were both judged to be cost-effective.
`The lowest value for cost per QALY gained (from the health system
`perspective) was USD 8,100. This was for the comparison of lifestyle
`changes with placebo, with lifestyle advice given as it might be in
`routine clinical practice (i.e. less intensively) – to groups of 10 patients
`- and with the optimistic assumption that there would be no reduction
`in clinical effectiveness. The highest cost per QALY was USD 99,600.
`This related to the comparison of metformin with placebo, as
`implemented in the DPP trial (i.e. with individual clinical care). The
`equivalent costs per QALY gained from the societal perspective were
`USD 23,800 and USD 99,200.
`
`Within the context of the US these were judged to be cost-effective. In
`health care systems with lower staff and/or medication costs these
`costs per QALY would be lower and the interventions, all other things
`being equal, would be more cost-effective.
`
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`Given this new, encouraging information on the prevention of or delay
`in the transition from IGT to diabetes, there is at least potential benefit
`from the detection of this condition through screening. Whether
`similar benefits will follow from the early detection of diabetes is
`another issue.
`
`3
`
`Aims of the meeting
`
`The aims of this WHO/IDF meeting were:
`• To review the scientific evidence for the usefulness of screening for early
`detection of type 2 diabetes.
`
`• To make recommendations relevant to health care policy, action and future
`research.
`
`• To explain these recommendations in a joint WHO/IDF Report.
`
`4
`
`Terminology – what is screening?
`
`The Group’s working definition of the term screening is based on that used in
`the WHO "Principles of Screening" document30 (September 2001 draft):
`
`“Screening is the process of identifying those individuals who are at
`sufficiently high risk of a specific disorder to warrant further investigation or
`direct action.”
`
`The definition goes on to say:
`
`“It [screening] is systematically offered to a population of people who have
`not sought medical attention on account of symptoms of the disease for which
`screening is being offered and is normally initiated by medical authorities and
`not by a patient's request for help on account of a specific complaint. The
`purpose of screening is to benefit the individuals being screened.”
`
`The term diagnosis refers to confirmation of diabetes in people who have
`symptoms, or who have had a positive screening test. In diabetes, the
`screening test may be the diagnostic test (e.g. a fasting plasma glucose => 7.0
`mmol l-1 in someone who has symptoms) or the first part of the diagnostic test
`if a second test (usually the OGTT) is used to confirm the diagnosis in
`asymptomatic individuals.
`
`There are several potential approaches to screening for diabetes:
`
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`• Screening the entire population (never actually suggested since all
`proposals have been, in some way, selective).
`
`• Selective or targeted screening performed in a subgroup of subjects who
`have already been identified as being at relatively high risk in relation to
`age, body weight, ethnic origin etc.
`
`• Opportunistic screening carried out at a time when people are seen, by
`health care professionals, for a reason other than the disorder in question.
`
`‘Selective or targeted screening’ and ‘opportunistic screening’ are not
`mutually exclusive since screening may be limited to those at highest risk. In
`opportunistic screening, the decision to initiate the health care encounter is
`made by the individual, albeit for reasons not related to the condition for
`which screening is offered. This needs to be distinguished from screening
`programmes in which the invitation to come forward and be screened is part of
`the programme.
`
`There is also ‘haphazard’ screening, characterised by a lack of a coherent
`screening policy. In such cases individuals may be invited to be screened
`irrespective of their risk (people in a supermarket, for example) or there may
`be no adequate explanation of the reasons for screening or no formal system of
`support for those taking part, whatever the outcome of their test.
`
`5
`
`Evaluating screening tests and programmes
`
`5.1
`
`General issues
`
`The sensitivity of a screening test is the proportion of people with the
`disorder who test positive on the screening test. (A highly sensitive
`screening test is unlikely to miss a subject with diabetes.)
`
`The specificity of a screening test is the proportion of people who do
`not have the disorder who test negative on the screening test. (A highly
`specific test is unlikely to misclassify someone who does not have
`diabetes as having diabetes.)
`
`Although it is desirable to have a test that is both highly sensitive and
`highly specific, this is usually not possible. In choosing a cut-off point
`a trade-off needs to be made between sensitivity and specificity, since
`increasing one reduces the other. The receiver operator characteristic
`(ROC) curve expresses this relationship. The true positive rate
`(sensitivity) is plotted on the y axis against the false positive rate (1-
`specificity) over a range of cut-off values. Tests that discriminate well
`crowd toward the upper left corner of the ROC curve (Figure 1). In
`ideal cases, as sensitivity increases, there is little decrease in
`specificity, until very high levels of sensitivity are reached31.
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`What should happen, in practice, is that ROC curves should be used in
`conjunction with pre-specified performance indicators (such as the
`proportion of cases that should be identified, what proportion of re-
`tests are acceptable).
` Some measure of ‘trade-off’ between
`performance indicators is likely to be necessary.
`
`Validity is the extent to which the test reflects the true status of the
`individual.
`
`Reliability is the degree to which the results obtained by any given
`procedure can be replicated.
`
`Reproducibility refers to obtaining similar or identical results on
`repeated measurements on the same subject.
`
`Screening tests must be shown to be valid, reliable and reproducible in
`the population in which screening is to take place. Uniform procedures
`and methods, standardized techniques, properly functioning equipment,
`and quality assurance are all necessary to ensure reliability and
`reproducibility.
`
`Predictive value relates to the probability that a person has or does not
`have the disorder given the result of the test. Thus:
`
`Positive predictive value is the probability of the disorder in a
`person with a positive test result and negative predictive value
`is the probability of a person not having the disorder when the
`test result is negative.
`
`The predictive value of a test is determined not only by the sensitivity
`and the specificity of the test, but also by the prevalence of the disorder
`in the population being screened. Thus, a highly sensitive and specific
`test will have a high positive predictive value in a population with a
`high prevalence of the disorder. This is part of the rationale for
`promoting selective or targeted screening. When the prevalence is low,
`as may be the case when the entire population (or the entire adult
`population) is screened, then the positive predictive value of the same
`test will be considerably lower. In this case, a high specificity drives a
`high positive predictive value. To avoid false positives (throughout the
`range of prevalence) it may be necessary to increase specificity at the
`expense of sensitivity.
`
`Screening tests may be used in parallel (i.e. a person is deemed to be
`likely to have a disorder if they test positive to either test). In this case
`the sensitivity and the negative predictive value are generally increased
`and the specificity and positive predicted values decreased.
`
`On the other hand, screening tests may be used in series (i.e. a person
`needs to be positive to both tests in order to be deemed likely to have
`the disorder). In this case the specificity and positive predicted value
`
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`are generally increased and the sensitivity and negative predicted value
`decreased. Tests in series have been advocated in type 2 diabetes (this
`is further discussed below) when, for example, a questionnaire may
`precede a fasting blood sample or OGTT and be used to exclude some
`individuals deemed to be at low risk of having the disorder.
`
`5.2
`
`Issues specific to diabetes
`
`5.2.1 Range of available tests
`
`Screening tests for type 2 diabetes include risk assessment
`questionnaires, biochemical tests and combinations of the
`two. The biochemical tests currently available are blood
`glucose or urine glucose measurements, blood HbA1c or blood
`fructosamine measurements. Each screening test needs a
`designated and pre-determined threshold or ‘cutpoint’ that
`defines high risk. Screening tests are usually followed by
`diagnostic tests (fasting plasma glucose (FPG) and/or an oral
`glucose tolerance test (OGTT) using standard criteria) in order
`to make the diagnosis.
`
`5.2.2 Evaluating screening procedures
`
`Meaningful evaluation and comparison of the performance of
`screening tests and procedures for diabetes should be carried
`out against specified criteria and should take into account the
`following basic principles:
`
`• People with known diabetes should not be included in
`the prevalence data used to calculate PPV
`• Selection of cut-off points:
`o should ideally be determined using ROC curve
`analysis because this considers performance
`over the whole range of cutpoints
`o alternatively these can be determined by using a
`common specificity or sensitivity
`o should take into account the aims of the
`screening programme, available resources to
`meet the workload which will be generated by
`the proportion of the population which will
`require further
`testing, and
`the
`importance
`placed on avoiding false positive and false
`negative results
`• A valid assessment of screening tests requires the whole
`screened population (or a sample of them) to have
`diagnostic testing, not just those who screen positive
`• Performance should be validated on a population
`different to that from which the screening procedure
`was developed
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`• A
`an
`between
`be made
`should
`distinction
`epidemiological and a clinical diagnosis of diabetes. An
`epidemiological diagnosis can be based on a single
`OGTT or FPG whereas a clinical diagnosis, in the
`absence of symptoms, requires confirmation by a repeat
`test.
`• The precisely specified objectives of the programme.
`
`5.2.3 Performance indicators
`
`A standard set of performance indicators should be used to
`evaluate a screening procedure or test and include: statistical
`performance (sensitivity, specificity, PPV, ROC - area under
`the curve) and the percentage of the population identified which
`requires further or definitive testing. Additional indicators
`include information on the cardiovascular disease risk profiles
`of
`identified
`individuals and measures of
`the economic
`performance of screening tests and population measures such as
`the acceptability of the screening programme to those invited to
`attend, the extent to which any lack of acceptability reduces
`uptake, the psychosocial impact of each screening outcome –
`positive and negative, ‘true’ and ‘false’ and the ability of those
`found to be at risk of future development of diabetes to modify
`these risk
`
`5.2.4 Performance of screening tests for type 2 diabetes
`
`These have been recently extensively reviewed32-35. Some
`caution is required in interpreting the statistical results reported
`in these reviews and below because in many studies the
`diagnosis of diabetes was made using diagnostic criteria which
`predate the current WHO and American Diabetes Association
`(ADA) criteria. Despite this, the data allow conclusions about
`general performance of the various approaches to screening for
`type 2 diabetes.
`
`5.2.4.1 Questionnaires
`
`Several questionnaires have been developed to screen
`for undiagnosed diabetes and have included a range of
`questions covering both symptoms and recognised risk
`factors. If a person presents as a result of any of the
`symptoms of diabetes (such as thirst, polyuria etc.) and
`is confirmed to have the condition then this process is
`diagnosis and not screening. However, it is conceivable
`that people identified as having diabetes by means of a
`screening
`test or programme may, retrospectively,
`recognise the presence of symptoms which were not
`acted upon at the time. However, since the main
`purpose of screening is to detect asymptomatic people
`
`9
`
`Boehringer Ex. 2003
`Mylan v. Boehringer Ingelheim
`IPR2016-01564
`Page 15
`
`

`
`with undiagnosed diabetes, questionnaires which are
`based on the symptoms of diabetes are not considered
`here.
`
`The original ADA “Take the test: know the score”
`questionnaire36 included both symptoms and historical
`risk factors. A modified version of this questionnaire
`has been evaluated by Herman et al37 based on data
`from the Second National Health and Nutritional
`Examination Survey and had a sensitivity of 83%,
`specificity of 65% and PPV of 11%. This questionnaire
`was subsequently tested in a community screening
`program in Onondaga County New York and showed a
`sensitivity of 80%, specificity of 35% and a PPV of
`12% 38 ,39.
`
`Griffin et al developed a risk score based on risk factors
`routinely collected in clinical practice40 and evaluated
`this in a hypothetical notional population with the same
`age-sex structure as England and Wales. No cut off for
`the risk score was prescribed but rather criteria for
`deciding a suitable cut point were proposed. An
`example gave a sensitivity of 77%, specificity of 72%
`and PPV of 11%.
`
`5.2.4.2 Urine glucose
`
`The usefulness of urinary glucose as a screening test for
`undiagnosed diabetes is limited because of the low
`sensitivity which ranged from 21% to 64% with
`specificity > 98% in studies which included performing
`an OGTT in the entire study population or a random
`sample of negative screenees32.
`
`Examples of such studies include Davies et al41 who
`used a self-test for postprandial glycosuria and reported
`a sensitivity of a positive urine test of 43% and
`specificity 98%. Hanson et al42 studied Pima Indians
`with non-fasting urine glucose and non-fasting OGTT
`and reported a sensitivity of 64% and specificity of 99%
`for a positive urine test for diabetes diagnosed on the 2-
`hour non-fasting post gl