Screening for Type 2 Diabetes - WHO

1 WHO/NMH/ Original: EnglishScreening for Type 2 DiabetesReport of a world health organization andInternational Diabetes Federation meeting world health OrganizationDepartment of Noncommunicable Disease ManagementGenevaWHO/NMH/ Original: EnglishScreening for Type 2 DiabetesReport of a world health organization andInternational Diabetes Federation meeting world health OrganizationDepartment of Noncommunicable Disease ManagementGenevaScreening for Type 2 Diabetes world health organization 2003 All rights reserved. Publications of the world health organization can beobtained from Marketing and Dissemination, world health organization , 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel: +41 22 791 2476; fax: +4122 791 4857; email: Requests for permission toreproduce or translate WHO publications whether for sale or fornoncommercial distribution should be addressed to Publications, at theabove address (fax: +41 22 791 4806.))

2 Email: world health organization does not warrant that the informationcontained in this publication is complete and correct and shall not be liable forany damages incurred as a result of its publication contains the collective views of an international group ofexperts and does not necessarily represent the decisions or the stated policy ofthe world health and its for type 2 Diabetes why WHO and IDF convened this of Screening on individuals, health systems and and prevention - the links ..43 Aims of the meeting ..54 Terminology what is Screening ..55 Evaluating Screening tests and specific to of available Screening of Screening tests for type 2 Combinations of Public response to Screening for type 2 Frequency of the risk of future development of type 2 current evidence relating to the efficacy of early relating to economic aspects of early relating to the psycho-social effects of early policies about Screening for type 2 aims and objectives of a Screening of health system choice of a test or priorities.

3 And political the evidence base .. need for evidence from randomized controlled need for observational need for economic use of modelling need for evidence on the psycho-social effects of early policies about Screening for type 2 Conclusions and 30 Annex 1 List of participants of the WHO/IDF and the past decade it has been obvious that the prevalence of type 2 diabetesis increasing rapidly. Unless appropriate action is taken, it is predicted thatthere will be at least 350 million people in the world with type 2 Diabetes bythe year 2030. This is double the current number. Equally alarming and lesswell known is the fact that, of these people, only around one half are known tohave the condition. This has been shown repeatedly in epidemiologicalsurveys. An added concern is that half of those who do present with type 2diabetes clinically already have signs of the complications of the has not yet been proven that earlier detection will improve the outcome ofpeople with type 2 Diabetes , but it seems logical to suggest that it may implication of this is that people need to be screened for Diabetes on aregular basis.

4 There is still uncertainty whether this should be done on apopulation-wide basis or just for those people who can be shown to have ahigh risk. It is also uncertain at what age the Screening programmes should beintroduced, if at report focuses solely on Screening for type 2 Diabetes in non-pregnantadults. It does not consider Screening for type 1 Diabetes , Screening for type 2diabetes in children, nor Screening for gestational Diabetes . This is not toimply that these topics are unimportant. On the contrary, they are eachimportant enough to require detailed consideration in their own is clear to both the world health organization (WHO) and the InternationalDiabetes Federation (IDF) that guidance is needed for both our membercountries and member associations. Because of this the WHO and the IDFhave come together to produce this document, which, though it poses as manyquestions as it answers, is a clear and logical start to a very serious hope that the report will provide guidance and provoke discussion andnew studies and in the long term will be of benefit to the many people in theworld with and at risk of type 2 Derek YachProfessor Sir George AlbertiExecutive DirectorPresidentNoncommunicable Diseases International Diabetes Federationand Mental health ClusterWorld health and its consequencesDiabetes mellitus is a metabolic disorder characterized by chronichyperglycaemia with disturbances of carbohydrate, fat and proteinmetabolism resulting from defects in insulin secretion, insulin action,or both1.

5 The current diagnostic criteria are shown in Table 1 Insummary, Diabetes is diagnosed if the (venous) fasting plasma glucose(FPG) value is >= mmol l-1 (126 mg dl-1), or if the casual plasmaglucose value is >= mmol l-1 (200 mg dl-1), or if the plasmaglucose value 2 hours after a 75g oral load of glucose >= mmol l-1(200 mg dl-1). In asymptomatic subjects, performing the test on oneoccasion is not enough to establish the diagnosis ( basis to treatdiabetes). This must be confirmed by carrying out at least one furthertest on a subsequent glucose tolerance (IGT) and impaired fasting glycaemia(IFG) are risk categories for the future development of Diabetes andcardiovascular disease (CVD). An individual falling into the IFGcategory on the fasting result may also have IGT on the 2-h value or,indeed, Diabetes .

6 If an individual falls into two different categories, themore severe one classification of Diabetes is based on aetiological types1. Type 1indicates the processes of beta-cell destruction that may ultimately leadto Diabetes in which insulin is required for survival. Type 2 Diabetes ischaracterized by disorders of insulin action and /or insulin third category, "other specific types of Diabetes ," includes diabetescaused by a specific and identified underlying defect, such as geneticdefects or diseases of the exocrine latest WHO Global Burden of Disease estimates the worldwideburden of Diabetes in adults to be around 173 million in the year 20023. Around two thirds of these live in developing countries. Diabetes isno longer a condition of developed, industrialised or Western countries.

7 Global estimates of the burden of IFG and IGT are notavailable, but the number of people with IGT is likely to be evengreater than the number with diabetes4,3. IGT and IFG are nowsometimes referred to as pre- Diabetes (a term not unanimouslysupported by those attending this meeting since Diabetes will notnecessarily develop in those with IGT or IFG).The Diabetes epidemic is accelerating in the developing world , with anincreasing proportion of affected people in younger age groups. Recentreports describe type 2 Diabetes being diagnosed in children andadolescents5,6,7. This is likely to increase further the burden of chronicdiabetic complications of the consequences of Diabetes result from its macrovascular andmicrovascular complications. (Some describe a third category neuropathic , whereas others classify the diabetic neuropathies asmicrovascular complications.)

8 The age-adjusted mortality, mostly dueto coronary heart disease (CHD) in many but not all populations, is 2-4times higher than in the non-diabetic population8, and people withdiabetes have a 2-fold increased risk of stroke9. Diabetes is the leadingcause of end stage renal failure in many populations in both developedand developing countries10. Lower extremity amputations are at least10 times more common in people with Diabetes than in non-diabeticindividuals in developed countries11, and more than half of all non-traumatic lower limb amputations are due to Diabetes . In developedcountries, Diabetes is one of the leading causes of visual impairmentand blindness12, with Diabetes require at least 2-3 times the health care resourcesof people who do not have Diabetes , and Diabetes care accounts for upto 15% of national healthcare budgets14, for type 2 Diabetes why WHO and IDF convened thismeetingThe main reasons for the current interest in Screening for type 2diabetes and the reasons why WHO and IDF convened this meetingare: that there is a long, latent, asymptomatic period in which thecondition can be detected16,17; a substantial proportion of people with type 2 Diabetes areundiagnosed (Table 2).

9 A substantial proportion of newly referred cases of type 2 diabetesalready have evidence of the micro-vascular complications ofdiabetes18; the rising prevalence19 of type 2 Diabetes world -wide; the seriousness of the immediate effects and long-termcomplications of type 2 Diabetes ; evidence supporting the efficacy of intensive blood glucosecontrol20,21 blood pressure control22 and blood lipid control23,24 , 25,26in type 2 Diabetes and accumulating evidence that treatment of hypertension,dyslipidaemia (for example lowering LDL cholesterol23,24) canprevent cardiovascular disease in people with type 2 increasing pressure from professional organisations, lay groups andfrom some of the member associations of IDF to institute screeningfor type 2 Diabetes if only to further highlight the increasingprevalence and public health importance of the from national and regional health authorities and individual health careprofessionals for guidance as to what should be their policies for Screening for type of Screening on individuals, health systems and societyPolicies and practices for Screening for type 2 Diabetes have profoundimplications for individuals, health systems and society as a for individuals include: the time and other resources necessary to undergo the screeningtest (or tests) and any subsequent diagnostic test (or tests).

10 The psychological and social effects of the results whether thescreening test proves positive or negative and whether or not thediagnosis of type 2 Diabetes is subsequently made and the adverse effects and costs of earlier treatment of type 2 diabetesor of any preventive measures instituted as a result of the individualbeing found to have Diabetes . These may include occupationaldiscrimination and/or increased costs or difficulty in effects on the health system and society as a whole are: the costs and other implications (especially in primary care andsupport services such as clinical biochemistry) of carrying out thescreening test (or tests) and the necessary confirmatory test (ortests); the additional costs of the earlier treatment of those found to havediabetes or to be at high risk of developing Diabetes orcardiovascular disease in the future and the implications of false negative and false positive results whichare inevitable given that any initial test will be a Screening test andnot a full diagnostic test (except in the case of an OGTT withmarkedly abnormal values).